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The price of lithium-ion batteries has declined by 97% in the last three decades (ourworldindata.org)
477 points by infodocket 14 days ago | hide | past | favorite | 318 comments

That's not the price of batteries in general, that's the price of Li-Ion batteries. Were Li-Ion batteries mass produced in 1991?

We used a Lithium D cell in a prototype wireless product at a startup I worked at in 1989. The cells were pre-production samples. I forget the name of the company that was producing them now (I think it was a Japanese company - there were no logos on these batteries), but we were warned not to let them short out as they would go off like a 1/4 stick of dynamite. We were pretty careful with them, but we did have a unit come back from the field that had pretty much burned up, nothing but a charred circuit board left and most of the plastic enclosure melted away.

Were these disposable lithium metal batteries or rechargeable lithium ion? They’re pretty different technologies. Both are prone to rapid discharge overheating problems though.

How much better than the competition were they then? Did you understand why you were using such a dangerous alternative?

We needed long battery life - 3 years for a small 8051-based board with a data radio (kind of like wifi in 1989) that turned on every second or so. We created a power control ASIC that kept the 8051 off most of the time - it would wake up when data was available for processing. This was a proof of concept project for the military not a consumer item.

Weight, I suppose. And silver+zinc was likely still more expensive.

I was never rich enough to own a laptop in that era, but I remember weight being the commonly espoused difference, or at least how it was marketed.

This illustrates a big problem in econometrics, specifically inflation measurement ("price indexes"): when comparing the prices of equivalent (baskets of) goods and services, "equivalent" gets harder and harder to define over longer time and space intervals.

The classic example is light bulbs [1]. If you use naive comparisons of like goods across years, with weighting by percentage of expenditures, to measure consumer/producer price changes from e.g. 1890-1930, you'll see:

1. decreasing weight in the basket and increasing price of whale-oil lamps over time 2. increasing weight in the basket and decreasing cost of light bulbs over time

But what you won't capture is that these two goods are both providing lighting, and that the switch from one to another provides a sharp drop in the price of light that is not captured by the change in prices of either in isolation.

Here it's the opposite effect, in that looking at Li-Ion battery prices in isolation overestimates the deflationary effect on energy storage prices.

This problem has also popped up in the context of measuring US manufacturing output over time. Specifically, the correction factors used to deal with this are called "price deflators", and their inability to deal with the pricing and business model of computer hardware may have produced an incorrect impression that US manufacturing output is holding steady or increasing, when it's actually decreasing [2]

[1] "Classic" as in used to draw the attention of the field in this important 1998 paper: https://lucept.files.wordpress.com/2014/11/william-nordhaus-...

[2] https://research.upjohn.org/cgi/viewcontent.cgi?referer=&htt...

'Overestimates' because at the start of the time series people were using cheaper alternatives to the very-expensive li-ion batteries.

> But what you won't capture is that these two goods are both providing lighting, and that the switch from one to another provides a sharp drop in the price of light that is not captured by the change in prices of either in isolation.

I wonder if there was any way to compute light emitted per source. Then you could calculate a price per unit of light and whale-oil lamps would be obliterated by incandescent light builds which would in turn be obliterated by LED light bulbs.

There is! That paper I linked does exactly that. It uses light to illustrate the point because it's particularly easy to calculate the comparative amount of utility per unit of cost regardless of technology, and show how it diverges from what naive price indices would show.

It's harder for something like batteries, where there are multiple relevant performance parameters to reduce to one utility heuristic. And good luck when the utility is subjective (clothes), still under study (food and nutrition), or ill-defined (media).

Planet Money had an episode where they used the metric "minutes of light per day's wages". Here's the transcript: https://www.npr.org/transcripts/503769949

But there are qualitative changes that aren't captured by this -- street lights are brighter and whiter now than they were in the 1990s for example, and those were brighter than oil lamps before them.

Note: that's a more accessible podcast/write-up of the paper I linked in my comment as [1]. If people want the denser in (in both good ways and bad) version, look up there.

Yup! That's a condensed version of a BBC write-up of that first paper I linked. Super influential in the field, but only percolated into popular media in the last decade.

They were not. In 1998, the second edition of Greenwood/Earnshaw's chemistry textbook came out, a magisterial survey of inorganic chemistry. They state that the major use for lithium is in lithium grease, but "looking to the future, Li/FeSx battery systems are emerging as a potentially viable energy storage system ... and a ... source of power for electric cars". The 1991 edition did not talk about batteries at all.

I still remember the PowerBook 5300 series that was released around 1996 and had to be recalled due to reports of fires with their then cutting edge lithium batteries. Apple had to rerelease the product with NiMH batteries IIRC.

The other commenter says that they were first introduced as a commercial product in 1991.

According to Wikipedia, they were preceded by two years by the first commercially-available nickel-metal hydride cells in 1989, so that would be an interesting point of comparison. Also nickel-cadmium and lead-acid have been around for a very long time.


I remember a lot of stuff having NiMH for a long time throughout the 90s, seemed like it took LiIon a lot longer to catch on.

We raced electric RC cars in the 90s (really my dad and brother - I mostly just liked the smells and ideas). But I know my brother said to win they always had to have fresh as new batteries and as I recall they were NiMH

Yes, performance of a battery declined over time, just as "battery health" declines on your phone today, for the same reasons. Mostly due to surface oxidation of the electrodes iirc.

Lithium-ion was never a good idea due to the fire hazard (in a crash they would just straight up explode, not even just cause a raging uncontrollable fire like LiPo, just boom) and Lithium-polymer could not support the necessary discharge rates (which I believe was also true of li-ion at the time too...). Early LiPo packs were only rated to like 0.5C or 1C peak discharge - this means, for a 2 amp-hour pack, 1C would be a discharge rate of 2 amps. Even then the packs did not really do well at their rated discharge rates - NiMH packs were far more tolerant of abuse in terms of discharge rates, in some cases you could push well beyond the rated spec and they would take it for a year or two's worth of sessions.

I was an "early adopter" on electric R/C airplanes back in the day (this would have been like 2000-2004) and the early stuff I used was mostly repurposed stuff from electric cars. The changeover to 4/5 or 2/3rds sub-C cells was a big deal at the time, the first "good" packs I owned were something called "HeCells" around 1800mAH or 2000 mAH, I also used KAN 1100mah cells. What I finally settled on at the time were these Sanyo "1950FAUP" cells which were extraordinary performers - we could push those cells to 70-80 amps peak discharge and they would take it. So in terms of the way LiPos are rated today[0], that is 40C discharge. This would only be doable for short periods, but it is necessary for launch and climbout (when the motor is running flat-out and the wing is basically stalled). Without the ability to sustain those currents it becomes very difficult to launch. Even still we did not "taxi" them like a normal airplane (or a normal model airplane), just wasn't enough power to get off the ground without a paved strip.

We typically expected about 10-15 minutes of flight time if you were flying normally, maybe 8-10 if you were really hotdogging it. So that means we averaged about 6C over the course of a flight (higher during climbout, less during cruising).

Another unsung miracle is how much motor technology has improved over the same period. My early motors were, again, repurposed brushed motors from Graupner's electric car lineup. We later moved onto some brushed Kyosho "magnetic mayhem" car motors that could push even higher levels of current. There was a Czech company called "Mega" who was an early mover on small neodymium brushless motors and that was a big deal at the time, they were far more powerful and far more efficient. Nowadays you don't even think about it, they're just a commodity, but at the time even a small brushless motor would run you about $130 or so!

[0] (tangent but it's kinda weird that NiCd and NiMH cells have traditionally been specced in amps but LiPo cells are specced in terms of "C discharge", obviously it's trivial to move between the two if you know the capacity of the pack but there's a definite difference in "style" of how the discharge rates are represented here...)

Likewise, and I was quite perplexed as a kid why The Secret of Nimh had no mention of batteries.

The first commercial/mass produced lithium ion batteries came out in exactly 1991 as a matter of fact! They were used in a Sony camera.

There's a graph there on market size, which shows the market size has grown 50,000x since 91.

This is a sort of meaningless metric, you can adjust your time frame to make the market size arbitrarily small because it was 0 before 1991.

Your parent specifically stated 1991 not "before 1991".

I think I understand what you mean but there was also a unfulfilled requirement before 1991. Back then (I'm 50.5 years old) cells didn't explode but then they also didn't set the world alight in terms of longevity either.

We had Walkmans and crappy clones that drained the shitty rechargeable cells we had at the time in a few hours. OK those things drove mechanical beasties - cassettes but cells/batteries were not particularly good before Li-Ion turned up.

Do you have any idea how something as simple as an iPod becomes exciting because no mechanical spinny things means power draw is much, much lower? It also helps if the thing isn't beige or grey. Apple are no more exciting to me than any other mob: design-wise, but they did get a few things right early on: "don't look shit". As it turns out, that simple mantra means that you get to >$1T t/o.

Now I own a phone that runs for around two days before charging. That doesn't sound too grand until you recall that just the GPS thing in it would have required 2U+ in a comms rack back in the day. The camera? If I kept an equivalent camera from the 1990s in my pocket then I'd be making silly jokes about it. The phone: I can stand on the top of Hay Torr and make a call.

Initial iPods used spinning disks. Solid state was not a factor in early iPod success.


It didn't really take off until flash and the colored assortment anyways tho

They started taking off when you could load them from a windows machine.

Ah yeah, correct. Weren't the first ones using Firewire IO? Just classic levels of insular on Jobs' part

edit: maybe not, plausibly just charging

IPod with a 40G disk was the only Apple product I ever liked.

Most of that seems true but orthogonal to my point, which is when comparing states of something with a power law growth, it is really easy to come up with big numbers that don’t contain any real information.

That 50,000x or whatever didn’t really give any information about the growth of a product over thirty years, it only really gives information about the growth during the first year which if it had been marginally different would give you a wildly different value for your “market growth today” number.

We should all be careful not to publish large numbers with dubious sources.

> We had Walkmans and crappy clones that drained the shitty rechargeable cells we had at the time in a few hours. OK those things drove mechanical beasties - cassettes but cells/batteries were not particularly good before Li-Ion turned up.

NiMH came out around the same time and it's fine. A good one has similar energy to a good alkaline. Not very far behind a small-cell lithium ion either.

Ok, we've add lithium ions to the title now. Thanks!

Yea, AA batteries have definitely not gotten cheaper

AA is a form-factor, not a chemical technology. You can get lithium AA batteries. You probably mean alkaline cells have not gotten cheaper.

I will second the notion that indeed AA batteries, whether Alkaline, Lithium, or Zinc Carbon, for purchase by consumer at a super-market checkout, have not gone cheaper recently.

I will even venture that consumer lithium-ion batteries, such as for camera or laptop replacements, do not appear to have gone cheaper over last, say, decade. I can only assume healthy profit margin by brands (Nikon/Sony/Canon/etc, Lenovo/Sony/Dell/etc). Third party cheaper batteries are available, of dubious quality, so I suppose that may be a sign of cheaper manufacturing...

I'm not quite so sure about that. The prices have remained relatively stable, but the capacities have gone up. I think on a per Wh basis they may have actually gotten cheaper still. That means that you've gotten more battery life and/or more useful power in the devices that are using the batteries.

Ni-Mh still seems to be the go-to for rechargeable AAs. I rotate four Ni-Mh Eneloops out in my wireless mouse.

NiMH has the advantage of having very similar voltage to alkaline. Lithium ion AA batteries wouldn’t work as direct replacements in a product designed to be powered by alkaline batteries.

And it's an excellent example. Technology gets better until efficiencies are maxed out and battery cell production can't be an exception. The only big outlier has been computer chips, where slowly shrinking cost per square mm (if it even sank?) was an insignificant footnote compared to the ever increasing ability to pack in more per unit of surface area. Lithium batteries have far more in common with alkaline batteries than with transistors for logical operations.

Power transistors for example I would also consider closer to alkaline cells than to logic, there has surely been a lot of progress in that field which eventually brought us the miracles of HVDC, but on a far more conventional scale.

Most technology follows an S curve. It starts out slow with initial experimentation until most of the dead ends and pitfalls are eliminated, then there is a period of rapid growth as the tech matures and gains mass market acceptance, then it levels off with all of the easy gains mined out and you see only incremental improvements moving forward.

The middle part of the S curve is when you see the dumbest articles about the technology, with people extrapolating the growth linearly and talking about how it will rule the world in a few years.

Yep, mobile phone batteries haven't either (just the battery, without the expensive replacement fee, because manufacturers are too greedy to make user replacable batteries).

Why are they so expensive? In particular Energizer and Duracell? Is there a recycling fee included in there or is Energizer and Duracell just gauging the public and not doing anything regarding recycling?

Nice that the cost has come down. Unfortunately, that which makes electric cars and planes feasible, namely energy density (Wh/litre) and specific energy (Wh/kg), has not improved that rapidly. The article mentions a factor of 3.4 over 30 years for energy density, ie 4% p.a., or doubling every 17 years. I think electric aircraft need another doubling or two in specific energy to become feasible, so another few decades :-/

If we fix everything except for aircraft, we will have done enough. At that point aircraft can keep using fossil fuels for a while longer.

Cars, trucks, buses, trains, HVAC, factories are what needs to be electrified ASAP.

Trains can already be electrified without the need for batteries.

For the case of buses, I think there is an elegant solution that they have begun to use in my city. Historically, they already have been electric cables around the city for pantograph buses. However, it is expensive to run electric cables around the city, so they are only a handfull of lines using this technology.

Now they are introducing hybrid battery / pantographs buses. Which I think a good compromise because you only need to equip a fraction of the line with electric cables, and the battery takes care of the rest. Because of that, you don't need a huge battery for the bus to be able to run all day. It can recharge periodically on the line with the pantograph.

Concerning trucks and cars, yes that shit needs to be electrified ASAP.

One big mistake Toronto, Canada, did was getting rid of its trolley buses in the 1990s https://transittoronto.ca/trolleybus/9503.shtml

If batteries do not make progress fast enough, synthetic fuels might be a temporary(?) solution. With these we can have the advantage of the high energy-density of hydrocarbon fuels for use cases like airplanes without having the climate effect of fossil fuels. Remember that the problem with fossil fuels is that they increase the amount of carbon in (short term) circulation which is what leads to further accumulation in the atmosphere or oceans. Producing synthetic fuels would remove carbon from the environment before releasing it on use again, leading to a net-zero effect.

> Producing synthetic fuels would remove carbon from the environment before releasing it on use again, leading to a net-zero effect.

Unfortunately, that assumes producing those synthetic fuels has no carbon output other than the fuel itself.

The process may have as much carbon emissions as it needs and even more as long as none of them can eventually be traced back to fossil sources.

„Fossil“ is the actually bad property of these fuels.

Methane and carbon being released from permafrost soil is an example of non-fossil sources, but yeah, the general sentiment of not releasing any more GHG into the environment is the objective for now. The more we can leave "captured" the better.

If you could use wind/solar for the energy source that would be a net improvement and not just net-zero.

The environmental impact and cost are of course important to consider, but for energy, there's also always the geopolitical aspect to comsider. Having the capacity to make fuels from plants means some independence from Saudi Arabia and Russia for the western world. The shock of 1973 has left its mark.

Having a huge supply chain for corn also drives innovation and scale in that industry, should corn become rare because of a drought, it would be relatively straightforward to redirect the corn supply into food.

When watching the video, what struck me as absurd is more the energy waste from meat production.

I doubt there is enough electricity available to also power the generation of synthetic fuels in high mass. Maybe for limited use cases (percentage wise)

Well, what energy where and at what cost? It's possible that there will be renewable overbuild to the extent that there are enough times of cheap or negative energy prices, especially in sunny locations, that can be used for fuel creation.

(The downside I must mention is that high capital cost low utilization low running cost => still high cost)

The USN have a solution in their back pocket: https://www.zmescience.com/research/us-navy-synthetic-jet-fu... , presumably for at-sea refuelling using surplus energy from the reactors of carriers.

Synthetic fuels scale up even worse than battery density.

And boats!

Intercontinental shipping is more likely to move to electrically-synthesized ammonia than to batteries.

Big aircraft are more likely to move to liquified hydrogen, synthesized on demand at major airports; initially burning it in turbines, eventually using fuel cells and electric drive.

Ammonia will be pretty easy to switch to; the main impediment today is just raw production capacity, which needs to be scaled up by three orders of magnitude. Ships can be retrofitted in place with new, bigger pressure-vessel fuel tankage and more complicated fuel piping. The changeover will need to be driven by regulation.

LH2 is quite a bit harder, but the rewards for success are huge. It might need entirely new turbojet engines, and maybe new airframes with room for bigger tankage. It certainly needs truly huge scale-ups in both methods and raw capacity to synthesize LH2, and in production of cheap aerogels to insulate the LH2 tanks.

The first usable LH2 transport aircraft will have an absolutely crushing advantage over kerosene-fueled craft anywhere they compete. Kerosene craft will gradually be pushed out to shorter routes and smaller airports. How fast this happens will depend mostly on how fast LH2 production can be scaled, and how fast new airframes can be approved and then delivered.

First and foremost, hydrogen production needs to be moved to renewable power. At current production levels it generates almost a billion tones of CO2 annually already.

And then, total efficiency for hydrogen fuel is much lower than batteries. In vehicles for example, while 70-80% of grid energy reaches a cars’ wheels, the figure for LH2 is about 25%, a lot more of it goes to production and transport than its actual purpose.

I think this clearly tells us that investing in new battery tech to increase density is a much more promising long term bet.

Hydrogen is an energy STORAGE medium, NOT an energy SOURCE.

The ONLY economically viable source of H2 today is cracking Natural Gas (and to your point, nearly always producing CO2 in the process).

From both a lifecycle efficiency and pollution perspective (if you accept the ridiculous idea that CO2 is a pollutant), we're way better off just burning the NG, which is already the cleanest carbon-based fuel there is.

NG is not a viable aircraft fuel. It is possible that cryogenic LCH4 could be, as SpaceX uses it, but its energy mass density is not enough to drive a wholesale conversion, as LH2's is. Batteries are also far from viable as energy storage for transport aircraft.

Obviously, the LH2 fuel must be produced electrolytically, from electricity generated from renewable sources like solar, wind, or geothermal, not from NG as it all is today; I specifically called that out in the text that the above pretends to reply to, so it is hard to see why NG-generated H2 is mentioned here at all. LH2 generated on demand at airports does not incur transport losses.

Identically, NH3 is today produced by consuming NG and exhausting CO2, which process also must be replaced with catalytic means powered from renewable sources, and H2 generated electrolytically.

And, obviously there are conversion losses from solar/wind to electric to separated H2 and to chilled LH2, and then to accelerated air, just as there are losses extracting crude oil, transporting, refining, transporting again, burning, and exhausting it. End-to-end cost, including externalized environmental cost, is what matters. We need a carbon tax to help drive conversion. But the favorable energy mass density of LH2 overrides enormous conversion losses, which is the whole point.

Oil is also an energy storage medium, but I don’t think that distinction matters at all here.

Are there any electric boats yet? Especially curious about the feasibility for shipping boats. The density seems to be less of a concern there.

I read about the Candela C7 boat last week. See https://candelaspeedboat.com/

There are several electric ferries in use in Norway and Denmark.

Example https://www.visitaeroe.com/ellen

These guys are doing some great things here in Seattle: http://purewatercraft.com

Recreational boats, yes, a ton.

Oh, forgot boats, right. Boats should definitely be on my list.

are ACs not already electric?

I guess furnaces are still largely gas, oil or wood burning... that doesn't seem like a technological problem though.

Gas furnaces are FAR more efficient than their electric resistance heating or even heat pump counterparts. Not to mention that a simple gas burner works with no moving parts (other than the solenoid valve) for decades with no maintenance, while heat pumps, in my experience, are far more troublesome than regular HVAC units, and still have to fall back to grossly inefficient resistance heating (even in a normal central Texas winter!) when temps dip below freezing. (One great thing about my parents moving several years back was leaving their $400-1000 annual heat pump repair bills behind. It wasn't just a bad unit - it was the third heat pump they'd had, and all (even from different mfrs!) were similarly troublesome, esp. for heating.)

Do factories require batteries?

I imagine factories can have customer arrangements with power suppliers (imagine an aluminum making factory), they could have their own batteries. Especially if the price for electricity varies, factories could charge their batteries when electricity is cheap, to save money.

To be honest, I don't know what they could use batteries for, but I also can't imagine that some aspects of factory work will be completely untouched by the upcoming battery revolution.

If every industry thinks like that ...

I can drive a car that's 20% heavier due to batteries. Nobody's going to fly a commercial plane that's 40% heavier due to batteries.

Some places, current batteries just don't cut it.

The requirements for fairly large power margins for safe operation at takeoff and landing generally prevent electric airplanes from making sense and achieving FAA approval, especially for commercial applications. We are decades away from viable electric commercial aviation. Even turbine-electric series hybrids weigh and pollute more than their native kerosene-burning equivalents.

Is there another industry that is facing similar physical constraints that would hamper a transition? I understand that reducing the carbon output in concrete production is difficult to the point of being nearly economically infeasible. Other than that?

There are some ideas about cement industry: [pdf] https://www.google.com/url?sa=t&source=web&rct=j&url=https:/...

Why not replace plane travel with hyperloop? Airplanes are high polluters, pay little taxes (none on fuel) , require massive bailouts and the only US civilian airplane maker is a soon to be anachronism...

On the other hand...the infrastructure requirements for a cross coast hyperloop venture...especially if impulsed by government would resolve a lot of things...besides couldn't it be used for cargo..Amazon might be interested ...and imagine the billboard/advertising opportunities..


> Why not replace plane travel with hyperloop?

You can’t replace a reliable mode of transportation with something that doesn’t exist yet. Even when it’s ready, it’d take decades. Political powers are reluctant to commit to something that’s going to take longer than their careers.

Then again, you don’t even need hyperloop. Germany has 250 km/h trains, those are more than enough for many routes.

Lots of countries have 330 km/h trains, and Japan is hoping to open the Chūō shinkansen within the decade, running at up to 500 km/h.

If one looks at the Wh/kg of the very best li ion batteries right now (about 250Wh/kg) and then compares it to the Wh/kg in avgas or jet a or diesel, it's nuts. Even if you lose 40-60% to waste heat. The amount of energy contained in those fuels is ridiculously dense by comparison.

You must also account for the engine / motor / transmission / drivetrain / fuel tank weight difference you can't just look at fuel weight alone.

In ground vehicles the weight of the engine and transmission and running gear is more than an electric motor and controller with much simpler usually single speed transmission and drivetrain especially diesel. Then there is structural batteries where the structure of battery helps replace some of the vehicle structure reducing wieght. This is why electric cars are starting to be competitive.

Planes are somewhat different modern turbine engines are relatively light for their power output and there is not much of a transmission on planes, usually variable props instead and fuel tanks are sort of structural. Although having many multiple props driven by small electric motors can have advantages which would be complicated and heavy to do with a drivetrain in a plane. Still electric planes are far from practical IMO.

Not only that, hydrocarbon fuels also disappear after use - meaning you get another massive boost from the weight dropping over time, as the energy required by an aircraft to cruise is partially dependent on it's weight. So the energy density of batteries is effectively even lower than on face value.

It looks like diesel holds ~10,700 Wh/kg[1]. That’s over 40 times the volumetric energy density.

I hope people find an electrical energy storage system (ie a battery) that’s cheap, and with high mass and volumetric energy density, soon. That would be huge for solving the impending climate (and pollution) crisis.

[1] https://en.m.wikipedia.org/wiki/Energy_density#In_chemical_r...

You must account for all the equipment to convert fuel into mechanical work as well. A battery is a large part of the equipment to covert electrons into useful electricity and electric motors and controller are comparatively light weight. Energy density is still higher I have done rough calculations that say batteries need to be at about 2000 wh/kg to be at parity with a diesel semi and the theoretic upper limit for lithium is 2600 wh/kg.

And the energy stored in it does not need to be paid :) That is why these companies make so much money of course.

Oil is free? Not sure where the Saudis got there riches from then.

Otoh sitting in the sun for a few hours to charge some battery via rays from the sun is itself free.

>Otoh sitting in the sun for a few hours to charge some battery via rays from the sun is itself free.

Sounds wonderful, please show the math.

You can't just forward project like that. The question is what people are working on. So far people main concern has been reduction in price.

This has reshaped and is reshaping the supply chain, has localized production and has massive improved production efficiency. Now we are slowly starting to approximate production of a scale and efficiency where we are approaching raw materials cost.

A huge amount of effort has now shifted into improving density as that is a vector to reduce cost. Huge money is flowing into silicon and lithium metal anode study.

There is some hope to get there faster.

> I think electric aircraft need another doubling or two in specific energy to become feasible, so another few decades

We have plenty of fossil fuel so if most of the world stops burning gas we can run aircrafts on fossil fuels for centuries. Even emissions wont be a problem as cheaper energy on ground can be used to capture green house gases and store them someplace.

> I think electric aircraft need another doubling or two in specific energy to become feasible

My trucker friends loved the electric semi trucks but what they were upset about was the charging time. Every hour the truck is idle you are basically losing money, losing rhythm of driving and so on. I think with aircrafts it is going to be an even bigger issue.

Does anyone know what stops us from building tech where batteries are rapidly switched ?

I’ve been buying 18650 cells for 6 years and they’re always the same price shrug

They even went up. I bought many various LG and Sony 18650 for around 2 dollars each (high quantity) 3 years ago. Now I pay about 2.80 for the exact same type.

The onesies-twosies 18650 market does not really represent the industry as a whole.

Demand currently outstrips supply. New applications are creating demand and there's expansion of existing users too.

Cost curve improvements won't arrive in every niche equally.

It's still early days. I guess this'll continue for a while yet.

The used 18650 market is going to be very interesting.

Yeah, same with mobile phone batteries (just the batteries, not the extra replacement fees for new, non-user-replacable batteries).

Has the capacity gone up?

No, I’ve been buying 2500 mAH batteries rated for 20A draw for 5.50 a piece, mostly Sony and Panasonic from illumn

I am curious, what kind of projects do you do with those batteries, what is their use for? Thank you

E-cigarettes or cannabis vaper if I were to guess, this is (other than RC drones) the only thing where you need the rated discharge current.

They’re very popular in the boutique flashlight industry

Bingo, it’s the nicotine vapor

I use 18650 cells over pocket cells in my hobby projects if possible: partly because I find it easier to get consistent quality 18650's in my local market (shipping lithium ion batteries is a hassle), partly because it allows me to use the same pool of batteries across many things (power banks, torches, different DIY-projects).

What battery holders do you tend to use?

Although Li-Ion cells are getting cheaper and cheaper every year, it still is worth salvaging the good ones from depleted laptop battery packs. When a laptop battery pack is gone it's almost always the case of one, max two, 18650 elements that failed, not the whole pack. I've built some good power banks using empty shells (very cheap on Ebay, Aliexpress etc.) and fitting inside the good cells salvaged that way. They last just like new ones once one discards the bad ones. The only caveat is that cells taken from laptop battery packs are not individually protected, that is, they don't employ the small pcb containing a protection against excessive charge, discharge, temperature, short circuit, etc. because the needed circuitry is already contained in the laptop battery pack. Power bank shells do indeed contain such protection, so no problems, but care must be taken into insulating the cells contacts so they cannot short, and before fitting them the user must charge each of them to a known identical voltage, so that once they're put in parallel (remember: no individual protection) the strongest ones won't discharge their energy on weaker ones.

I was under the impression that mixing and matching cells (by model or by age/number of charge cycles used) can be sketchy. For example, if you have a very heavily used battery in series with new battery, everything may look okay externally, but you may end up over-discharging the older battery.

What are your thoughts on this? Haven't had any issues? Or do you take steps to mitigate it?

Since he mostly talked about having them in parallel, this might not be an issue for him. I also think a bms can solve that issue

Yes, I can confirm. I use them only in parallel, and they usually come from the same battery pack. A series connection would require extra care to select them for identical characteristics, and the use of a BMS to keep them balanced, avoiding the strongest ones to discharge at reversed polarity through the weakest ones, which would be a recipe for disasters. BMS circuits however can't do miracles; too different cells shouldn't be used together anyway.

Match them based on internal resistance and capacity after running some tests. Most people don't even really bother with the resistance.

You'd be far better off matching them based on percent of original capacity and internal resistance. A 3200mAh cell worn to 2600mAh is in far worse shape than a 2800mAh cell worn to 2600mAh, though you'd probably also see a big difference in internal resistance between them. You might also consider checking IR at various states of charge, if you're being comprehensive.

... and at that point, short of massive automation in a fireproof area, you're almost certainly going to come out ahead buying new cells.

Does this come with a “know what you are doing” caveat? I’d be scared of creating an electric firelighter in the process.

Also assuming money is no object. Is it as good for the environment to recycle the old battery and buy a refurbed one.

Yes, sorry for not stressing this enough: extra care must be taken when dealing with Lithium cells. They pack a lot of power in a small space, and can be extremely dangerous if mistreated; even physical damage with no heat involved can turn them into fireworks, so always treat them the right way. Never ever short them or apply excessive charge or discharge, use only good quality chargers and never ever let them unsupervised during charge. If a cell catches fire accidentally, don't attempt to extinguish it with water or sand as they are 100% ineffective, keep a specific safety container for Lithium cells at hand and if you feel you can can fit the cell into it to contain the fire in a bunch of seconds hold your breath and do it, otherwise get the f out of there because the fumes are extremely toxic and would seriously harm you before even getting a burn.

> ... because the fumes are extremely toxic and would seriously harm you before even getting a burn.

I mentioned it elsewhere, but https://en.wikipedia.org/wiki/Hydrofluoric_acid_burn is a very relevant read on the nature of "toxic." Most of the rest of the stuff isn't much friendlier.

> Does this come with a “know what you are doing” caveat?

Yes, and I'll suggest that a disturbingly large fraction of the people doing this on YouTube don't know what they're doing, and are being brutally unsafe with the batteries, even if it works.

I've done battery pack rebuilding semi-professionally for a few years (I was rebuilding ebike packs for most of North America from about 2015 to 2018), and the people screwing around with the used/recycled cells scare the hell out of me. In no particular order:

* They don't care to invest in a spot welder and they solder directly to the terminals. Every datasheet out there for 18650s that mentions soldering says the same thing: "DO NOT solder directly to our terminals." You spot weld a strip on and then solder to that. Soldering to the terminal puts a ton of heat into the end of the battery which then flows into the cell windings. The separator is usually plastic. You really don't want to weaken it. With a spot welder, I can put my finger on the terminal immediately after spot welding, and I can spread out the welds in time. If I want three welds (six spots) on a terminal, I can do one weld on each cell, then come back for the rest, and keep the temperature "comfortable to a fingertip." I cannot do that soldering.

* They tend to take a single snapshot of cell capacity, maybe internal resistance, and then assign cells that way. Unless they organize them by wrapper color for aesthetics, ignoring the cell capacity and behaviors. Some cell chemistries will degrade far faster than others, and you'd ideally like to not have a mess of stuff in the same pack.

* They recharge dead cells with no idea how long they've been dead. Lithium cells are physically stressed at full charge and fully empty, and a cell that has been empty for a while may have very real internal physical damage, such that it will fail later. I won't charge anything under 2.5V unless I know exactly how and when it got there, and if it's much below 2.0V, I still won't put voltage to it. The risk of a lithium battery runaway and fire is too high for my tastes. Lithium battery runaways, beyond lighting stuff on fire, tend to emit things like HF, which you very definitely don't want to breathe. It doesn't hurt a bit while it's killing you, because it destroys the nerves first. Health-wise, you're actually better off if the battery venting is flaming, because the mixture of gases coming off that is somewhat less toxic. Again, it depends on the particular chemistry what you get. It's never anything friendly.

Unfortunately, "recycling" lithium batteries isn't really established yet, and most of what seems to pass for "recycling" is the cells getting shipped to China, having new ends put on to hide the spot welds, and then getting a shiny wrapper and sold with impossible capacities to vapers for $0.75 or something silly. The highest capacity 18650s are around 3600-3800mAh, and don't source an awful lot of amps in the deal. Anything claiming higher (again, in the 18650 form factor) is certainly a lie.

You can do it, if you're careful, but by the time you've properly characterized the batteries, I'm not convinced it's worth the time/effort. Those who claim it is tend to skip a lot of checks and be really, really casual with their packs. To their credit, they rarely catch fire, but the whole "DIY Powerwall" crowd using scavenged and abused cells is not a good example to follow.

Thank you so much for sharing your experience. It's valuable.

Do you know any best practices about who does this right, and how it can be done both safely and economically? If necessary with automation and large scale.

I really don't. I expect there are some people doing it, but I also expect they're not busy posting their stuff to YouTube. I learned what I learned with a lot of time spent in datasheets, PhD theses on lithium, and a background in electrical engineering that helped me make sense of the weird gaps. I'm no longer doing much with lithium beyond the occasional personal pack (which I still build to the same standards I built other packs to).

The best advice I have is to learn all you can from reading things, not watching things. The bits and pieces of solar/battery/energy work I've seen on YouTube as people link them tend heavily sensational and "WOW I NEARLY BLEW MYSELF UP!!!! big O YouTube emotion face" and I've no interest in any of that.

Also, you shouldn't assemble a pack with the batteries above about... oh, 3.5-3.6V/cell. Down there, there's typically not enough energy for the pack to get exciting if something does short. It'll get hot, it may vent a cell (again, do not breathe), but it probably won't have enough energy to enter a thermal runaway, which is something you want to avoid at all costs.

Following up a few days later, someone did send a video my way that I agree with every aspect of - the guy does a very safe, competent build, with correct techniques, and builds a far better and safer pack than most of the commercial packs I've seen.


> HF, which you very definitely don't want to breathe. It doesn't hurt a bit while it's killing you, because it destroys the nerves first.

Sobering information.

I replied with some questions about the safety of this, as I had some concerns when reading it.

Aside from the issue I mentioned in reply, the only real caveat would be "know the basics of working with electronics without shorting things or electrocuting yourself" and "check out some youtube videos on rebuilding 18650 packs so you don't do it in a horribly wrong way".

> "check out some youtube videos on rebuilding 18650 packs so you don't do it in a horribly wrong way".

Bad idea, because about 90% of what they do is fine, and 10% is very, very wrong. Unless you know what you're doing, it's almost impossible to tell which is which.

Fair enough. I haven't seen any of the 10%, but I'm sure they're out there. As an alternative to saying "go find info", how's this: https://www.youtube.com/watch?v=3KDiecphUk8 ?

I just gave it a quick skip through, but the guy seems to know the correct approach.

If someone on YouTube is soldering directly to terminals, in any form, they're badly wrong and I wouldn't trust the rest of their judgement.

I'm not going to evaluate someone's YouTube video on battery repair, sorry. There's no way I can "skip through it" and have any sense of what they're doing, and I generally try to avoid YouTube as a source of information. You'll find far better material on Endless Sphere, though there are plenty of dangerous ideas there.

The DIY energy storage community is always on the hunt for warehouse sales, closeouts, auctions, etc... on battery packs. There is a cottage industry around buying them up and "shucking" them for the 18650s. It's a lot of work and requires some luck, but you can get hundreds of unused 18650s for like $.50 each.

Does this require special knowledge and experience? I would be afraid to try it myself as I suspect that I or my devices would be harmed, either in the process or later on.

Yes, it does. It's not rocket science, but one must know what he is doing, and as with everything that can become really dangerous, it is better to err on the side of safety.

To my knowledge, this is the best informational site around regarding various battery technologies (including Lithium), and how to use them safely.


Parallel cells will automatically balance as the charged cells feed the discharged cells. There is absolutely no point in trying to balance them.

There is. Preventing overcurrent, as the automatic balancing process you are describing can be over hundred times faster than the charging rates the batteries are rated for.

You both are right, but there is a caveat: the cells internal resistance.

Connecting cells in parallel is inherently safe if done when they're brought all at the same level; from that moment on they won't charge or discharge across each other because the current draw will always bring them at the same voltage, therefore having zero current from cell to cell. The problem is however when one or more cells degrade with age, therefore we have more efficient cells in parallel with less efficient ones. That is not a problem safety wise as well, because as before they'll always be at the same potential, but should their degradation change their internal resistance to a point it's a lot higher than their normal one, then we would have the good cells with lower internal resistance sustaining the most current during charge or discharge, and that could be dangerous. To avoid situations like that one, never implement charges faster than the one that could be sustained by a single cell. Let's say one 2Ah cell can be safely charged at 2C max, that is, 4 Amperes, if we build a pack of 3 of those cells in parallel we would be tempted to charge them at 6C, that is 12 Amperes, which would work in a new pack with all cells that equally balance the current. But if (when) one or two cells degrade their internal chemistry increasing their internal resistance, we'd be left with the remaining good cell(s) drawing the most current, which will largely exceed their individual rating, overheating them and potentially making them explode (that's also when individual cell protection make sense). There's actually a case in which a cell chemistry is so degraded that it can't only store the same amount of current, but also the same voltage, and this could be a problem in parallel packs, but the battery performance drop should have warned us a lot before this happens.

So, all we need is to keep the charge current as low as the current sustainable by a single cell, and we're safe. Slow charging also benefits the overall cells life. Don't worry about connecting unprotected cells in parallel, as they balance themselves: all laptop batteries have balanced series of unbalanced parallels. For example, a 6 cell pack contains is arranged as 2p+2p+2p (2 cells in parallel in series with 2 cells in parallel in series with 2 cells in parallel) while 9 cell packs use 3 cells parallels; series cells are balanced through the BMS, but parallel cells will self balance. What is important is to keep series groups balanced and protect against excessive voltage and charge/discharge current.

cells will definitely drift a little bit over time and they absolutely do need to be balanced.

(or else overall pack capacity and discharge performance will be lost - the discharge curves are not linear, when a cell is "dead" it drops rapidly, and that means you've effectively lost that chunk of your pack in terms of capacity and ability to discharge).

it's not instant of course, so it's not like you need to do it every single time, but the trend over time is definitely for them to move away from ideal balance with multiple charge/discharge cycles rather than into balance

Do you know a good source of info on how to test these cells?

This is really cool, but could anyone familiar with the domain estimate how far we are along the S-curve?

I.e. it took a long time for things to ramp up, then they accelerate really quickly and then they slow down again. Think Moore's Law, which is dead now.

What would be the price estimate for 2030, for example. I think we're now around $100 per kwh (or something like that), what should we expect for 2030? $60? $20?

> Think Moore's Law, which is dead now.

Look again. Moore's law in terms of single threaded performance is dead. In literal terms of number of transistors on a wafer, it's still increasing exponentially, just slower. And in terms of what mattered when people cited Moore's law, the decrease in price/performance, it's still exponential, just slower and multi core.

It will end, as all exponential trends must end lest they consume the universe, but the end is not yet in sight. Recently chips have started to go multi chip and three dimensional. So even when we finally hit that scaling limit, we haven't quite reached the end of exponential progress.

With the current silicon manufacturing processes, I'd say the end is in sight. Every node shrink is taking longer and longer and getting more and more expensive to fabricate.

We've been reliant on node shrinks to push things further. That hard limit is 0.2nm (silicon atom size) we are at ~2nm gate features.

It remains to be seen if we can get to that 0.2nm size, I honestly don't think we can push much further past the 2nm size (I'd imagine 0.5nm will be the limit).

That, to me, is very much being "in sight".

3d chips. Imagine current size with 1 million layers. Sure it will start with just a few layers. And many obstacles to be overcome like temp and delay. But one day our cpus will look like little cubes. Moore's law can continue for at least another 30 years

Couple of problems.

First, how do you cool such a chip? Sure, you could add a bunch of transistors but the thermal costs per transistor will stay the same. Assuming similar design but adding 20 layers, how would you account for your CPU now consuming 600W?

Second, The tech doesn't exist. The problem we have is that layering chips today is basically growing crystals in a controlled fashion. Defects in lower layers spoil upper layers. Today that's already a problem (CPUs today have ~7 or 8 layers). Can you imagine the problem of 20 or 30 layers?

Who knows, maybe we'll come up with solutions to both problems, but that's a big maybe. My bet is that instead we focus on architecture designs. We revisit old but deemed too expensive concepts like an async CPU.

This is real, shipping technology.

See 3d nand flash cells, see stacked cache and HBM memory. All the usual characters are working on it. Intel, AMD (TSMC), Samsung.

Cooling is an issue, but there are solutions.

3d cells for nand aren't the same as 3d CPU cores. Nand is incredibly simple which makes it possible to do things like 3d cells which would otherwise be more complicated.

There's a reason memory can generally beat computational cores to smaller node sizes. It's because highly uniform circuits are much easier to manufacture. A lot of problems present in CPU logic cores (such as cross talk) just aren't present to the same extent in NAND cells.

Maybe stuff like Upmem (many small CPUs embedded into memory) can take off then?

Possibly, that'd be one of the "major architectural changes" that I mentioned earlier. Things we've simply not tried yet because they are too radically different from the way hardware currently works.

Sorry to have to ask.Could you please show a Wikipedia-like intro to Upmem?

It may be a simple typing problem, but Wikipedia doesn't seem to have it.

I found a previous HN submission about them: https://news.ycombinator.com/item?id=20766283

> Today that's already a problem (CPUs today have ~7 or 8 layers).

No, I think x86 passed 14+ layers at least half a decade ago.

So I'm behind :D. What I remember is them trying to cut down the layers due to yield issues. Guess it's creeped back up again.

That's a continuation of moore's law, it's the same as having a bigger chip horizontally, or more chips. You can make giant chips but you need giants bank accounts.

It does not reduce price per transistor because each layer still has to be manufactured the same way

Sort of true, except you can use cheaper process scales for some of the layers.

The silicon is not actually the expensive part.

There are still many ways this may change. 3d transistors (which are currently used), different materials, and 3d chips (stacking layers of chips).

We are not yet close enough to the end to say where it is, so that's out of sight IMHO.

Like I said, cooling is going to be a major issue that doesn't currently have a solution (as far as I know) Even if it does, you are going to run into the real problem that even if you can cool a 600W CPU, would the average customer WANT to have such power hungry parts? Now imagine the problem in server space where the CPUs are already constrained by power consumption.

The entire reason cloud service providers are looking at and advertising ARM racks is the power savings from operating them.

I think there are almost endless gains to be had on the software side. Current software is so insanely inefficient you could probably triple the speed of the average computer without any hardware upgrade.

hasn't it always referred to transistor count and not performance?

Oxford Dictionary says: "the principle that the speed and capability of computers can be expected to double every two years, as a result of increases in the number of transistors a microchip can contain."

Which notably mentions performance. I have often interpreted Moore's Law to be the fact that doubling improvements in performance will continue roughly every 16-18 months, but not always directly proportionally to transistor count -- other ways to squeeze out doubling performance gains arise and often in unexpected places.

Oxford Dictionary doesn't know what Moore's law is, then.

Moore's law was an observation by Gordon Moore, co-founder of Intel, relating to the doubling of transistors per densely integrated circuit chip every 24 months. Originally, it was every 12 months, then every 24 months, etc.

Moore's second law, which isn't as well known, relates to the exponentially increasing capital cost of manufacturing ICs.

Single threaded performance and overall performance are quite different. But I'm not sure that Oxford is the most authoritative source here, as they are talking about a "computer" which is an awfully vague term. Wikipedia uses transistor count of an IC, which is much more specific:


Would be interested to know if the process inside Oxford's is as precise to distinguish, or if they intentionally dumbed it down.

It has always referred to the minimum of the cost-complexity curve for integrated circuits. The progress of Moore's Actual Law has never stopped.

The thing people mean when they are talking about the deceleration of single-threaded CPU performance is actually Dennard scaling. Dennard said that density and power efficiency were complementary in such a way as to keep areal power constant. That was true until it suddenly stopped being true. If Dennard scaling had continued you'd be using a 20GHz CPU right now.

Did you read the whole comment? I edited it, but that part was in there from the beginning, just in different words.

I agree with you, I just think you weren't making your case strongly enough by implying that Moore's Law referred to more than just transistor count.

> ...I just think you weren't making your case strongly enough...

I get where you are coming from, but this is one of the most aggravating types of comments.

Fair enough

I am sure there is some sci fi novel where species compete for neutron stars because they are a very dense compute substrate.

In the Perfect Imperfection by Jacek Dukaj [0] has something called "Remy's curve" [1].

On the curve you can find:

- Ultimate Computer is the computer using the best hardware as allowed by the physical constants of our universe. See also physics of computation.

- Inclusions are in essence 'pocket universes'. They are created for specific entities to run hardware in a dedicated universe with physical constants different from ours, allowing for better performance than those in our universe

- Ultimate Inclusion is the inclusion with the best possible set of physical constants in the entire multiverse

Seth Lloyd wrote a paper "Ultimate physical limits to computation" [2].

[0] https://en.wikipedia.org/wiki/Perfect_Imperfection

[1] https://en.wikipedia.org/wiki/Perfect_Imperfection#/media/Fi...

[2] https://arxiv.org/abs/quant-ph/9908043

Not neutron stars specifically, but Accelerando by Charles Stross covers this.

That was a good book, it challenged many of my assumptions.

Asimov's "The Last Question" is close, though the focus is on entropy rather than any kind of space wars.

Isn't Three Body Problem kinda like this?

Is that book worth reading ? I am half-way through and I still don't see the point ;)

I read all three books. The first was a couple of years ago. But from memory, half-way through the first should be enough to tell. If you haven't seen anything worthwhile yet, you won't by continuing.

It looks like $156 in 2019 & $137 in 2020. Estimates are $100/kwh by 2023-24 and $58/kwh by 2030.

I do wonder how a dramatic shift towards Li powered cars will effect the price. We may see demand outpace supply for a decade or more. I hope it is the other way around because cheap lithium batteries flooding the market would have many positive implications.


It's very unlikely that large companies would leave that much money on the table (they will invest in supply).

There is no doubt that energy storage will be huge and worth investment at massive scale.

As to Li-ion, well the future is good, but not so certain.

If musk is to believed, (and I think he's on point with this), $50/kWh will likely come within the next 5 years.

So next 9 years? My expectation is beyond Tesla, the rest of the industry will have hit on that sub $50/kwh price point. That is going to make a lot of things really interesting. $2000 for a 30kWh home battery backup? Who wouldn't get one?

To further this, with climate change leading to more and more extreme weather, I'm expecting that power outages are going to be semi-common (assuming the grid doesn't invest in battery backup).

> $2000 for a 30kWh home battery backup? Who wouldn't get one?

Very few of the people that would currently benefit from a domestic backup battery could afford $2k, and most of the people who do have $2k to spare don’t live in places with unreliable electricity.

The overlap isn’t zero, but… for example, I visited Kenya with an ex of mine, we met a local friend of hers, that friend would’ve benefited from a more reliable electricity bill, but her monthly rent and utility bills combined was equivalent to about $85 and she couldn’t afford to move.

> Very few of the people that would currently benefit from a domestic backup battery could afford $2k

California, a state of 40 million people, would disagree with you ;)

Not just referencing the blackouts we had last summer: CA also is heavily invested in solar power, and as a result, power is much cheaper during the day than at night (assuming you opt into time of use pricing). A battery for $2k would pay for itself in California quickly, because you can charge it when power is cheap during the day and run off battery when power is expensive at night.

Plenty of other US states have had blackouts as well; my parents in PA now own a generator due to repeated blackouts last year. If they could have bought a battery for $2k, they probably would have: generators are loud and dirty. And Texans certainly had a bad time with blackouts recently as well.

> A battery for $2k would pay for itself in California quickly

Anyone who can find a spare $2k can buy one and quickly find they now have more than $2k spare, but you’d be amazed how many people, even in a rich part of the world like CA, don’t have as much spare cash as the average developer.


Like I said, “not zero, but…”

This is such an unrealistically pessimistic assessment.

You just need to count the number of rooftop solar installations there are in the world to get an idea of the market size. Another $2k investment to get significantly more value out of an existing multithousand outlay would be a no brainer for most of them.

I’m not saying nobody will value them ever under any circumstances, I’m replying to someone saying “Who wouldn't get one?” with “you’d be surprised…”

Mainly I’m expecting grid-corrected batteries of this type to be owned and operated by power companies and governments rather than by individual home owners; and most privately owned batteries to be the ones in cars rather than permanently attached to houses.

> California, a state of 40 million people, would disagree with you ;)

How explode-y is this battery? I hear California also has this problem with forest fires and it seems a fire and giant batteries all over the place would be two flavors that do not go well with each other.

Probably less explody than a propane tank. Turns out that pretty much any form of energy storage can release a bunch of energy in a short time if pushed hard enough.

I was thinking the same thing until someone pointed out that lard stores a ton of energy but you can't really make it explode. I hope.

But you can make it burn!


> With so much oil-rich food on hand, including lard, cheese and more than 10 million pounds of surplus butter stored by the federal government, the fire was a hot mess — fast-moving, destructive and difficult to put out.

Now I want to know if someone has made a butter-fuelled hybrid rocket, and not why not.

Home Storage is typically LFP (LiFePO4) nowadays. And those are hard to ignite.

> Very few of the people that would currently benefit from a domestic backup battery could afford $2k, and most of the people who do have $2k to spare don’t live in places with unreliable electricity.

My expectation is that with climate change, unreliable electricity is going to affect a lot more places. The polar vortex that knocked out the Texas grid is likely to be a more frequent and more extreme event. ACs running more frequently will likely lead to more brown outs.

Assuming our grids don't get major updates (I'm pretty pessimistic about this), we are looking at more and more outages in the future. It's certainly possible that smart grids could significantly reduce outages, but that will take too many actors working together to ever really fly.

For example, if the grid could coordinate with your heating and cooling, you could distribute AC usage to avoid tripping the grid.

Barring such a grid, homes having batteries would allow owners to skate through brown outs. Further couple that with solar and they could survive even major outages (hours or even days).

> The overlap isn’t zero, but… for example, I visited Kenya with an ex of mine, we met a local friend of hers, that friend would’ve benefited from a more reliable electricity bill, but her monthly rent and utility bills combined was equivalent to about $85 and she couldn’t afford to move.

A 1kwh battery would probably be a pretty positive impact. Add on a 300W solar panel and you'd have something that would extend the amount of electricity the have. That'd come in at ~$400 (assuming $50/kwh). Not enough to run an AC, but enough to keep the lights on and maybe run a fridge.

Otherwise... yeah... not much good news for places that can't afford such batteries.

> For example, if the grid could coordinate with your heating and cooling, you could distribute AC usage to avoid tripping the grid.

This is already done. It’s a blunt system, but it is done.

I was offered $5/month off my electric bill to add a device to my AC unit that would be able to turn it off for up to 15 minutes per hour. (I declined, because my AC at that time was not able to keep up even running constantly.)

A 1KWh battery is affordable now using off-the-shelf lead acid batteries.

There is no advantage using Lithium batteries (at present) as size and/or weight is not critical for domestic applications.

The whole point of the discussion is that Lithium is still not cheaper than Lead acid.

Lead acid batteries suck for more reasons than just their size and weight. One major disadvantage is that the faster you discharge them the less of their charge you will actually recover[1]. Additionally, discharging them below 50% capacity significantly reduces their life in terms of total cycles (even for cells rated for "deep cycle" operation)[2][3] so you need to oversize your battery system to get the same effective capacity if you want your cells to last. Lithium batteries suffer from neither of those drawbacks.

If those weren't enough, even when treated well (not discharged too deeply) lead-acid batteries don't last for as many discharge cycles as lithium iron phosphate cells. If you do the math, for batteries cycled daily modern LiFePo batteries are about the same TCO as lead-acid despite the higher up-front costs because the lithium batteries will last significantly longer and you don't need to buy as much absolute capacity for the same effective capacity. Here's a good presentation on this: https://www.youtube.com/watch?v=BRqRDZh74F0

[1] http://omahamakergroup.org/2015/05/14/battery-derating-and-c...

[2] https://www.pveducation.org/pvcdrom/lead-acid-batteries/char...

[3] https://www.solar-electric.com/media/wysiwyg/cyclelife2.gif (Graph shows cycles (y-axis) vs average depth of discharge (x-axis) for a typical "deep cycle" lead-acid battery. Note the y-axis is logarithmic.)

"most of the people who do have $2k to spare don’t live in places with unreliable electricity"

Increasing the mix of renewables in the electricity networks will mean most people live in places with unreliable electricity going forward. The proposed $2k 30kWh home battery backup could well be the adaptation many of us have to make.

um, no, we are not going to have unreliable electricity because people's lives depends on it. We will have grid scale batteries, and the grid will charge you more or less depending on when you are using energy. it does not make sence to have such essential equipment randomly distributed through the population where I have to fight my landlord to repair the damn thing or have it not cause a house fire, while the guy is out of the country on holiday and couldn't give a rat's ass

It does make sense to invest, but also makes sense to build these things at scale. Having a team of people micromanage your roof and electrical system already costs nearly same as equipment.

um, yes, it's happening already in areas where intermittent supplies make up a sufficient percentage of the energy mix (e.g. South Australia). In an ideal world we'd keep the rollout of intermittent sources below the level at which they cause instability until grid scale batteries are invented, however that's not the world we live in.

My understanding is that neither of the major outages in SA in recent times have been related to intermittent supply issues (i.e. the first major incident was related to trips caused by weather, the second was related to a gas using supplier failing to increase supply due to some market regulation minutiae that was subsequently changed).

Regardless of the realities in SA (I’m not convinced by the offical explanation of the first outage at least, there are credible alternative theories), it’s well understood that beyond a certain level, introducing intermittent suppliers into a network designed for baseload generation will cause instability. I don’t have the figures to hand but IIRC more than very low double figures as a percentage starts causing trouble.

> and most of the people who do have $2k to spare don’t live in places with unreliable electricity.

A home battery in many places is basically free money. Renewables mean there is an extreme oversupply at some times and an undersupply at others. Owning a battery hooked up to the grid means you buy power at oversupply times where the power goes in to negative pricing and then sell it back at other times in the same day where it is very expensive.

Reusing old car batteries for this purpose might become the next bitcoin mining with warehouses full of repurposed batteries buying and selling power.

> A home battery in many places is basically free money.

Only if its a free battery. Otherwise, its an income stream with an up front cost.

Which is why its not common, but with battery prices coming down and dirt cheap second hand batteries on the horizon, this is going to become a big industry.

An old tesla battery with only 50% capacity remaining is still perfectly good for this kind of use even if not so great for driving.

> Which is why its not common, but with battery prices coming down and dirt cheap second hand batteries on the horizon, this is going to become a big industry.

Maybe briefly, especially where retail customers with some installed renewable generating capacity can leverage the latter to take advantage of net metering laws designed to bring renewable capacity to the grid, because otherwise their stuck buying at retail and, if allowed to sell back at all, selling at wholesale.

Bur cheaper batteries mean proper utility players (e.g., a joint operation of PG&E and Tesla) are building large, purpose-built storage facilities, often colocated with generation facilities, with lower marginal costs for real estate and interconnection than separate facilities and better access to financing than small operators.

Storage is going to be a big industry going forward, but the period where home storage (or storage by anyone but major utility players) is a viable financial hack rather than just a backup plan for grid failure will probably be brief unless artificially subsidized to encourage distributed storage.

Old car batteries are at the end of their life because they have low capacity or have shorted cells.

A battery with only 50% capacity is pretty useless for a car but if you get it for cheap, its a great deal for a home battery.

The realities of batteries is that most of the cells will be at 90% capacity while a few will have dropped to 50%. So recycling really can be just plucking out the good cells and breaking down the few old cells.

Those 90% cells will also have a pretty nice degradation curve as most of the loss happens within the first few years of operating.

1. Here in CT with our abundance of trees, a large fraction of the state loses power for the better part of a week every couple of years when a windstorm comes up the coast.

2. Batteries need not just be for power outages. Net metering, granular demand-based energy pricing, etc are all reasons to get a battery for your house.

Value for money is not my argument.

I’m just saying loads of people for whom it would provide benefit don’t have $2k spare money to invest.

To put a different spin on it: the price point for the cheapest consumer unit should be way lower than that… unless you force landlords to install it at their own cost (as a landlord myself: a $2k legally mandated expense would not be happy fun times, but I could and would suck it up).

And even then, you’re still thinking in terms of the richest economies, and first quartile incomes in developing nations would struggle with $25 backup batteries let alone $2000.

One belief of mine which is shifting from all the replies I’ve been getting, is that I’m increasingly surprised how bad everyone’s telling me that America’s fundamental infrastructure is.

I understand your point.

I don't think of the infrastructure here as _bad_, though.

We do have the occasional outage after a storm, as I described. But, even if the uptime were as low as 99%, which it is not, I would not want to pay the cost of making the grid significantly more resilient than it is.

My electricity uptime has never been as low as 99%. South coast UK for the first 18 years of my life, total downtime would’ve been at most half a day, in 30-60 minute fragments, ~99.992% uptime. Never once failed when I was back there for 7 months to help provide care for my mum. Likewise Sheffield for about a year, and that place had an annoying prepay electricity meter.

Rural Wales for 3.5 years? 30 minutes of downtime total, ~99.998% uptime. Similar total downtime in Cambridge, but I was there 8.5 years, so 99.9993% uptime. I don’t think it’s ever failed me here in Berlin.

That in particular is why I’m saying here that American infrastructure looks bad. It’s not the only way, TBH, but it is so in a new and relevant way I wasn’t previously expecting.

I don't doubt that electrical service in nearly all the UK has _much_ higher uptime than the service here in Connecticut.

I could be wrong, but I suspect that the infrastructure in the two places is built essentially the same way. I think the crucial difference is that Connecticut has so many more trees. Downed trees break the lines all over the state whenever a windstorm or a snowstorm comes through. (Come to think of it, most of the UK doesn't get snowstorms, either).

I'm just saying that never for a second would I consider trading any of those trees for additional uptime. Nor do I want to pay the utility providers whatever it would cost to bury all those lines in the ground where they'd be safer from storm damage. I'd rather have a week without power every couple of years.

I'd be curious to know if the story is different in rural or semirural Scandinavia.

There are plenty of places in US where electricity is not entirely reliable, and that includes some fairly wealthy suburbs. FWIW I'd get such a thing for myself even though we see outages maybe once a year - it's less hassle than a generator to keep the fridge running.

$2k maybe not but you can grab some chinesium 1 kW generator pack for well under 200$ these days, and fuel it with distilled alcohol. Good enough for a grid backup to keep the refrigerator and lights running.

> $2000 for a 30kWh home battery backup? Who wouldn't get one?

Because it would be a lot more than $2k to get put it in your home. If you do the math on a Tesla powerwall, the raw cost of the battery should be right around $2k too. But it actually costs more like $8k per powerwall.

That's for a few reasons.

Competition is low. There are only a few players in the home battery space and they are similarly priced.

Demand is high. Even with the higher price, the wait list to get a powerwall is more than a year out.

My expectation is a few things happen over the next 9 years.

I expect that battery production ramps up to a high degree.

I expect that the EV market will eventually be saturated

With those two things, I expect that EV manufactures and the likes of tesla will end up with more batteries than than demand. When that happens, you can expect that the cost of battery products will start to tumble as everyone that manufactures batteries starts to try and sell them for whatever application will buy them.

Things that could spoil my assumptions?

Power companies might decide now is the time to really buy batteries. That could keep demand outpacing supply.

We could see new applications of batteries that aren't currently on the table, such as battery powered trains.

The EV market could not saturate. This could be due to battery production capacity severely lagging EV demand. This could be due to anything from manufacturing plants running into major issues to supply chain problems.

But, I'm an optimist. I expect to see battery tech and manufacturing continuing to build out at a fast pace.

Oh, and eventually the expensive part of a battery system won't be the batteries but rather the install cost.

Battery powered trains seem really unlikely to me. It's hard to imagine a situation where it's cheaper to do a battery powered train than a train track that supplies power (aka how most subways work).

I can think of a few usages for it.

Batteries could get a train up to cruising speed requiring a smaller train engine and less fuel.

Batteries could save on line expansion, instead of installing a 3rd rail for the whole line, they could go a 3rd rail every 50 miles for 10 miles.

I agree a 3rd rail would be cheaper in the long run. Batteries could help bridge the gap.

The rest of the world doesn't live in high density built up areas. Many small crops farming trains in rural areas can not and will not be allowed to run power through the tracks in above ground situations.

The rest of the world uses overhead lines for powering trains (I'm a bit shocked to learn that this is not the norm in the US, actually)

At least in the UK, a 3rd rail was common. IDK about the rest of the world but wouldn't surprise me.

Some major cities in the US had overhead powered "trolleys". But, car lobbies destroyed those :(.

I would rather spend a few thousand more for a natural gas generator, it will run indefinitely as long as you have natural gas.


If the whole grid goes down, your gas likely won't be there.

If you add solar, then you could indefinitely run in most circumstances.

I don’t live in Texas, I live somewhere that the natural gas doesn’t go out because people will die if it does, so our infrastructure is winterized and maintained. We get some -30F every winter and the natural gas service is always there.

You could swap out the NG generator for a diesel one with a day tank and then you don’t have to worry about NG service :)

A 30kwH battery wall is going to last 6-12 hours at most anyways.

I can’t recall NG service disruptions on a large scale in my state, and I’m 37.

60kWh for 4k then? What about 120kWh for 8k?

Point being you could target your outage range based on what you want to prep for at a fairly low cost (assuming $50/kWh).

Add on a solar system to any of these and you'd have indefinite power without a reliance on surrounding infrastructure.

For my home, 30kWh would give me ~24hr of power.

Even if you want a fossil fuel generator, you could have an auto switch to battery for the short outages so you don't have to go crank on the generator.

My whole house generator runs on natural gas. Indiana natural supply gas is stable and afaik never stopped in the last 20 years. It automatically fires up 6 seconds after power goes out and runs my entire house including EV charger. It’s fairly quiet, cannot hear with windows closed.

Cost like 5k and 2K install. Really hard to beat that in the near term with battery.

No it doesn’t do the demand shift part of a battery, but it’s pretty clearly better as an emergency solution, at least for my needs.

And when the natural gas runs out you use what?

It doesn’t go out where I live, but you could instead get a diesel generator and not have to worry about utilities

You can actually get a tri-fuel generator that can run off gasoline, propane, or NG (with some minor fiddling required to convert between the three).

However, it's still a lot more hassle to set this up compared to a battery pack that "just works".

That's not what I meant. Eventually, it will go out for the entire planet. It is not an unlimited resource. Then what?

People in general is not aware there are physical limits with energy sources and materials. We won't grow forever, actually we'll probably shrink once we hit the limits.

It's going to be a shock for a lot of people, specially in techno-optimistic communities as HN.

NREL has a great report on that, although it is focused on utility-scale battery storage: https://www.nrel.gov/docs/fy20osti/75385.pdf

Moores law isn't dead:


You probably mean Dennard scaling is dead. The breakdown was around 2006.


AAs with 500 mAh capacity and 50 mA charging was a marvel at the time. My greatest invention was that I connected bicycle dynamo directly to a small windmill and upped the voltage with diode ladder. It gave only 50 mA, but alas, that was what those batteries were rated for. Wind blows 24/7 so it was remarkable if you compare with solar panels. https://www.youtube.com/watch?v=XYorx9C-OEE&t=26s

Started to wonder why there is a switch on the charger box. Finally dawned on me: You cannot have the LED blinking and using 20 mA when your total energy production is 50 mA.

I don't think this applies to Duracell or Energizer alkaline batteries unfortunately :(

Of course reading the article they are talking about Lithium Ion batteries.

> unfortunately

Sounds good to me. Single-use, landfill bound products typically shouldn’t be as inexpensive to the consumer as we’re used to.

I used to get free batteries (size of my choice, I always chose the more expensive rectangular 9v ones) as an official member of the Radio Shack Battery of the Month Club.

Ah what memories. Tandy Radio Shack in Australia operated the same "Battery of the Month" club in the mid 1980s.

I always got the 9V too, which I used for my "150 in 1" electronics kit.

I would just buy some Panasonic eneloops(NiMH - not an ad, just the battery I have went with after researching this quite a bit) whenever you need to buy alkaline batteries. They are about twice as expensive but are rechargeable 2000+ times, hold their charge for over a year, and don't degrade very much. Eventually all of your devices will have eneloops in them and you will stop buying batteries altogeher.

I try to use NiMH as much as possible, but there are still a number of applications for which alkaline is superior. First, alkaline usually has more energy. Second, the voltage is more predictable. For devices like door locks that are battery powered and can detect a low battery, alkaline works great. NiMH has lower voltage and looks dead before it is. And lithium (not lithium ion) batteries have a very flat voltage curve and tend to die rather suddenly almost before the device can detect they're end-of-life.

NiMH have 1.2v instead of 1.5. That ist sometimes a problem for cheaper devices that don't have a good voltage regulator. For example Flashlights are notably dimmer.

eneloop is now produced by FDK, so there are many rebranded products. I often buy Fujitsu one because it's cheaper and they will never change OEM since FDK is owned by Fujitsu.


It's not nearly as dramatic. But they've surely gotten cheaper. As evidenced by how they have displaced carbon-zinc cells in almost all applications.

I checked Radio-Shack's 1981 US catalogue. $2.79 for a 4 pk of store-brand AA alkaline cells. That's $8.20 or so today. You can today, apparently get an 8 pk of Duracell from Wal-Mart at $7.50. Or an 8 pk of store brand alkaline AA cells from Wal-Mart for $3.20.

you're paying for the brand, shelf position and other advertising

cheap and reputable supermarket brand ones last just long

GP meant price for alkaline batteries did not come down.

Another point to consider is if you leave the alkaline battery in for too long will the chemical leak and ruin your device? The damage to your device from a broken battery could easily exceed the cost differential. I don't have solid evidence that brand names work better in this regard but I have definitely experienced repeatedly generic batteries having white corrosive crystaline stuff formed all around them.

People should quit buying alkaline batteries anyway. NiMH batteries are great for just about every application you'd use a throway for, and you only have to recharge them about twice to "get your money back."

The starting voltage is lower and drops faster making them not ideal for some applications and just annoying for some others (ie. motors start slow and get slower quicker than Alkaline).

Charge speeds also suck unless you get some of the fancy expensive chargers.

Yeah, there are some things they aren't great on but for most things they are fine.

> Charge speeds also suck unless you get some of the fancy expensive chargers.

This has been a total non-issue to me. I have 30 or 40 batteries running around total, keeping 4 spares on the charger is no big deal

>cheap and reputable supermarket brand ones last just long

Absolutely not. There are plenty of Youtubers testing this theory. Here is a pretty credible reviewer


I personally have had nightmarish results with Amazon Basics Alkaline. In my experience these batteries have a greater tendency than other brands to leak over time and have destroyed multiple electronic equipment that I have owned. It was a big mistake on my part because I bought a large package of them, installed them and then didn't realize that many of them leaked until it was too late and they have eaten away many terminals in the different devices I put them in.

> I personally have had nightmarish results with Amazon Basics Alkaline.

I did say reputable!

re: the video, he should really test more than a single pack of batteries of each type...

How do you tell the difference between a battery brand that is more expensive because the battery has greater capacity (“heavy duty”, “extra long life”, etc.) and a brand that is more expensive because of the brand name? Last time I looked in the supermarket there were no comparable metrics printed on the packaging.

You can't, and you don't know who is private labeling what, either. If you can get a data sheet, the better companies have more detailed data sheets.

Personally, I like the Energizer (primary, i.e. disposable) lithiums for nice things like my old HP logic dart that will sit in a drawer for a long time between uses, and Panasonic (formerly Sanyo) Eneloop NiMH batteries for most other things, and the cheapo Costco batteries for when I really don't care.

The three major US brands of alkaline batteries all have warranties for corrosion damage. I don't know of any other brands that do. I have seen corrosion in every brand of alkaline battery I've ever bought but have never tried to collect on any warranty.

“Energizer will repair or replace, at our option, any device damaged by leakage from Energizer MAX® Alkaline batteries either during the life of the battery or within two years following the full use of the battery.” https://www.energizer.com/about-batteries/battery-leakage

“Duracell guarantees its batteries against defects in materials and workmanship. Should any device be damaged due to a battery defect, we will repair or replace it at our option.” https://www.duracell.com/en-ca/technology/battery-care-use-a...

"In the unlikely event of alkaline battery leakage, any battery operated device that is damaged by RAYOVAC® Alkaline Batteries will be repaired, replaced or refunded, at our option, as long as the batteries have not expired or been mixed by expiry date and/or battery type.” http://www.rayovac.com/support/warranties-and-guarantees.asp...

I have a unproven suspicion that Rechargeable Energizer may actually be Panasonic cells. I tend to see them both marked as made in Japan and they both seem to be great quality.

Could be. I have no special insight into Energizer, but generally, the private-label product you buy today might not be the same six months from now. And even if they are Panasonic cells, they might not be identical to Eneloop, either.

The private-label guessing game cuts both ways, too: there are 2nd-tier alkaline manufacturers that swear they are a contract manufacturer for at least one of the major US brand names, with portions of their factory they can't show you because then you'd find out. Even if it's true, it doesn't mean the battery they sell you will be built to the same standards, with the same materials, or put through the same QA as the battery they make for someone in the battery business.

Looking at a couple stores, the difference is around 50 cents per AA vs. 70 cents per AA at moderate pack sizes. That's good in comparison but it's about the same price it was a decade ago. Even comparing to 1990, when "alkaline" wasn't yet the default, they were about the same price. "Alkaline: These cost about $2 to $3 a pair for C or D flashlight cells, and about half that for the AA and smaller AAA penlight batteries."

At best you can say they've dropped along with inflation, which is a factor of 2.

No question. Same thing you see in the generic pain relief aisle (ibuprofen, acetaminophen, et al), and many common grocery items.

10 pack of AA Rayovac batteries at Walmart: $3.20

Eight pack of AA Duracell: $7.47

Pretty ridiculous. For $7.78 you can get a 24 pack of ACDelco AA batteries (granted I don't know how that brand stands up on quality).

Pretty misleading title. In 1990 you could buy a AA duracel for 30 cents[0] update: older model. Alkaline may have been higher (see comments). Presently at Walmart you can get them for about 68 cents (24 pack for 16.24[1]). That's a nominal price increase of roughly 100%, although of course in real terms, it is flat (30 cents in 1990 were about 63 cents today). But those are alkaline batteries. This article is comparing the costs of prototypes of Lithium ion batteries in 1991 to mass production unit costs today. That unit costs fell massive from prototype to mass production stage is neither newsworthy nor interesting.

[0] https://www.nytimes.com/1990/01/20/style/consumer-s-world-co...

[1] https://www.walmart.com/browse/household-essentials/aa-batte...

> In 1990 you could buy a AA duracell for 30 cents[0]. Presently at Walmart you can get them for about 68 cents (24 pack for 16.24[1]). That's a nominal price increase of roughly 100%, although of course in real terms, it is flat (30 cents in 1990 were about 63 cents today). But those are alkaline batteries

I think you're misreading your sources. The NYTimes article says zinc-carbon AAs cost $0.30 each in 1990 (which, IIRC, are pretty crappy). The article doesn't give a clear price for alkaline AAs, but it sounds like they used to cost about $0.50-$0.75 each back then ($1.02-$1.53 each in today's dollars).

Then there's also the fact that in 1990, probably the only alkaline batteries available to consumers were name-brands in smallish packages. Nowadays some store-brand batteries are pretty good and cheaper. For example, you can get AmazonBasics AA alkalines for $0.90 each in a 4-pack, and $0.45 each in a 20-pack [1]. These are apparently manufactured by Fujitsu [2].

[1] https://www.amazon.com/AmazonBasics-Performance-Alkaline-Bat...

[2] https://onezero.medium.com/unraveling-the-secret-supply-chai...

That's a good point. I'll make the correction. It's still nothing near the percentage of the headline but is more accurate.

Did anyone really read the title thinking that the article was about alkaline batteries? I think not.

The title is not misleading. It's incomplete, as titles are by nature. Titles are not supposed to include all caveats and modifications. The title also doesn't say that the decline is measured in dollars. Probably the price has dropped much less or much more when measured in other currencies that have moved relative to the dollar. The title also doesn't mention whether it's adjusted for inflation. It also doesn't specify whether that's the price at the consumer level or the price paid by manufacturers. Whether it's when you buy the battery in America or somewhere else on the planet.

As long as a title doesn't deliberately seek to mislead, it's not misleading. The intended audience expected this to be about lithium ion batteries.

> Did anyone really read the title thinking that the article was about alkaline batteries? I think not.

Lithium-Ion were not in widespread use 30 years ago. So if we are just considering the price of Lithium-Ion, that would be the price from the first commercial product, which I expect was expensive for the time (it dropped in price around 30% in just a few years).

I read the title and thought it was battery capacity/$, not Lithium-Ion specifically.

> Did anyone really read the title thinking that the article was about alkaline batteries? I think not.

I did. For me "battery" without any context or other modifiers means some kind of consumer alkaline battery.

I did, mainly because alkaline batteries are the ones I use on a daily basis.

Semi-related rant : I'm baffled that most AA batteries don't display their capacity. It's literally the most important spec. Models vary between 400 and 3400 mAh!

If they have the word zinc on them, they're about 400 mah.

If they have the word alkaline, they're about 3000 mah.

And there isn't much in between. There are a few other weird chemistries, but they're never on the sweet price-performance curve, so avoid them.

That's not entirely true, capacity greatly depends on current draw and there is significant variability between brands (e.g. https://www.powerstream.com/AA-tests.htm)

Long time ago I stumbled upon a great website with a Wh/€ (the metric that really counts) for almost all brands, but I couldn't find it right now

Anything I own that's discharging at 2 Amps (!) no longer uses AA batteries. All those devices now have built in li-ion batteries.

AA batteries are relegated to clocks, TV remotes, doorbells, and other low drain devices.

In that scenario, all alkaline are pretty much the same.

I only use batteries to put them in socks and hit people.

In that scenario, all different battery types & chemistries are the same.

Batteries and coffee are the 2 supermarket things which amaze me. How is it possible there isn't some regulation on them having to display anything. Nescafe sometimes have "number of cups" displayed but sometimes they literally only have weight in grams. Next in line a hygienic products with also convoluted units but they seem to always have the "number of washes" at least.

Both the number of cups of coffee you get out of 200g of Nescafe and the number of washes you get out of 1 kg of washing powder will vary (depending on how you strong you like your Nescafe and how dirty your clothes are). The same is true for deodorant or shower gel. I think weight/volume measurements are fine for almost everything.

Packages for things like dishwasher tabs usually have a number on them (in addition to weight/volume, which is mandated to be on the packaging).

What other information besides weight (mass) in grams would you want? I mean sure, percentage of Arabica vs Robusta maybe, or lightness of roast, but the weight is exactly what you want and the most neutral and fair information regarding how much you get (and how much you get out of it).

Caffeine content labelling would be a big one. Could also be applied to things like cola.

Exactly! The most important question is how much caffeine is there. They market them as "strong" or "mild" and then they have the "new" "strong" and then they added the strength indicator. One has 4/5 dots the other one has 2/3 dots. Why not disclose caffeine content and let me decide how strong that is? Every other time I switch which coffee I drink or when I drink at friends house I get either headache or sleepy because I cannot maintain my caffeine intake

Replace 'price' with 'production cost', and factor in inflation, and maybe there's a decline over time even for alkaline batteries. But at such a low production cost, the shelf-space is likely to be the biggest factor at point of sale. That, and the mark-up will be set at whatever the market will bear.

> What’s promising is that prices are still falling steeply: the cost halved between 2014 and 2018. A halving in only four years.

I would imagine not all technologies drop in price the same amount as production increases (the "learning rate"), and at some point there might be limits to how much cheaper something really gets to produce.

The relevance relates to climate change. Our ability to scale battery production cheaply is pretty important for a range of green technologies. My main take-away was that we haven't hit those limits yet, lithium-ion batteries are continue to get cheaper as the capacity produced increases.

The price vs market size graph is a good summary: https://ourworldindata.org/battery-price-decline

The article itself is clearly about something else, so maybe try to have the title fixed instead of shoehorning another topic into the discussion? Message hn@ycombinator.com and ask them to add "LiIon" to the title if you feel that it needs clarification. Just look what a mess these unrelated tangents on other battery chemistries have made in the comment section already.

Edit: I sent an email.

Edit: dang changed it, see https://news.ycombinator.com/item?id=27431665

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