I recently set up my own off grid solar system in a tiny cabin that I designed and had built.
I used the Solar Controller+Inverter Combos recommended on this site (Growatt) but ultimately switched to ones by Renogy. The Growatt one I purchased has a wifi adapter and app - wifi requirement was a deal breaker when remote. The renogy one has a Bluetooth adapter and app, plus feels better designed (though actually I think the internals are all pretty similar).
There are a couple surprise gotchas I didn’t know:
1) These Controller+Inverter combo units require a battery to turn on. This means: if your battery runs completely out of charge, you have to get electricity from somewhere to charge your battery a bit before the Controller+Inverter will turn on and charge your battery again. I was pretty annoyed at how not “off grid” this felt.
2) Temperatures below freezing are bad for batteries. I purchased a Renogy 48v smart battery with self heating. Unfortunately less sun in winter means less energy, and heat production is energy intensive. I’m not at the cabin 100% of the time so I have to take the battery with me when I leave to avoid spoiling/freezing it. Still not sure how I’ll ultimately get around this.
> Still not sure how I’ll ultimately get around this.
If it's portable, your option works well.
For year round off grid use, there's something to be said for sealed lead acid, or flooded lead acid - they don't care about being cycled while cold (capacity is down and the voltage sags a good bit), and as long as they don't get too deeply discharged, they don't freeze.
A single panel, facing south, absolutely vertical, will shed snow and if you have no other loads, is usually enough to offset controller loads and self discharge over time to keep the batteries fully charged (and therefore not freezing) over winter.
There's no way you'll generate enough heat on electricity to keep a battery bank (or cabin) warm in the winter most places. I've got 5kW of panel on my office, and still can't manage that for a small, well insulated shed.
I live on 25 ha of forest, have an axe and saw, and heat with wood. Let me tell you: you want to use the saw for everything but splitting. Axes are fine for burly cavemen.
Anyway, in a cold climates like mine an acre would not be enough to keep you warm because trees grow slow when it's winter six months out of twelve. It takes a lot of wood to keep you warm, and one tree gives surprisingly little wood. After a handful of years you'll have clearcut your measly acre and still have another couple of decades to go before it becomes harvestable again. I'd say you want at least 10 acres if you manage it well and the soil and drainage are at least half decent.
They grow faster since they already have a root structure, the size is consistent and the wood is generally straigter (the japanese have a similar technique for extremely straight cedar logs)
By the time you get to 100 acres you can basically heat your house with the stuff that blows over in storms and the remainder can yield a nice cash crop every couple of years, giving space for the other trees to grow. Personally I'd prefer a chainsaw for anything but the most incidental cutting, and a hydraulic woodsplitter (rented) to get the job of preparing firewood for a while year done in a short time.
An acre of trees should be enough to give you an average of 4 kW of thermal power year round, way more than you probably need. Though at 1 W/m^2 how much industry an area of trees could support was the binding constraint on industry for a lot of recorded history. Especially there was always pressure to turn forests into farmland.
Could get by on much less than an acre if it were managed, but better to have more land and be able to keep it as unmanaged forest. That'll also produce fresh game and give some buffer on the lumber supply for lean years. How much rain falls is strictly out of my hands.
Seems to me that if you want to solar heat a cabin, a solar panel is going around the horn. Design the cabin to be a solar collector, like a greenhouse.
You’d still need backup heat production (heat pump, or wood burning, or fossil fuel, or electrical off batteries) for the inevitable month long ‘gray and cold’ stretches, or you’re gonna freeze.
Single purpose but not reliably there heat capture methods add cost and maintenance.
It’s often more cost effective to have a general purpose method that while not as efficient in one case is generally more overall (cost) efficient.
Pretty sure you don’t live in Central Europe or areas like northern Michigan?
There are weeks with zero direct sun, just low cloud cover, scattered snow, and cold cold cold.
I was in Michigan once when Lake Superior froze over, shore to shore.
Unless the place is so well insulated you can keep it warm purely with body heat, you need supplemental heating in climates like this. The sun is not always shining.
As that thread confirms, you do need backup in a cold climate, even with a ton of insulation. Amounts of insulating including R50 and R70, which is pretty mind blowing (and are difficult and expensive to accomplish in practice due to thermal bridging/‘leaks’).
Some folks in less severe climates (like New Hampshire) seemed to get by with baking and other managed appliance heat. That does require you spend time doing, and orient your activities around, things to produce heat to stay warm. Some will find that palatable, others won’t.
Posters in Colder climates (like Ontario) noted propane, or thermal mass heaters (such as the rocket heater in the thread).
‘Then the propane could make up the modest difference on long cold cloudy stretches.’
Hypothetically, for the lithium batteries, what if you made a big stainless steel vacuum wall insulated enclosure? Or just a metal box with r-60 value of foam around it?
The amount of heat needing to be generated can then be calculated based on the average temp over a longer period of time, and those batteries I don't imagine have to be "warm" exactly.
Lithium batteries don’t need to be warm for discharge (generally and with an asterisk), it’s charging. Discharge while freezing causes slower chemical reactions (aka lower discharge current), but that is rarely a huge problem compared to the charging problem.
Any charging around or below freezing causes pretty quick destruction of the cells as the chemistry switches to a more favorable destructive one way electroplating process instead of the desirable (and reversible) ion exchange process.
A common engineering solution to this has started to be temperature dependent shunts that route charging energy to heating pads around the battery until the battery temp gets above a certain safe point.
It adds complexity, cost, and adds several undesirable failure mode however, and Lithium battery cost is already a major factor in these systems, so if you’re in a situation where you can’t reliably temperature control your batteries (cold climate, non-conditioned battery space), lead acid is still a very viable and often desirable chemistry instead.
Round trip efficiency isn’t great with them, and you have to way over provision to get good cell lifespan, but it works.
They do not need to stay that cool at all. When used for solar, the C rate for charging usually never exceeds .2C for overpaneled systems. And usually never goes beyond .5C for discharge. So the heat generated is very small. Now when I am pushing 30-100C rates with a lithium polymer, cooling is an issue. this is why nissan leaf cells were recalled. The battery size was too small for the application, and they overheated which caused significant degradation rates. This is not an issue for solar. Just keep them at room temperature and they are fine.
It's good practice to snake a water pipe around every lithium cell anyway in big packs, because otherwise one bad cell can self-heat to the point of catching fire, even while other nearby cells are cold. The flowing water means the bad cell can't get to the point of fire.
Is 5kW not enough to heat the cabin? I guess it must be really cold where you are. Modern heat pumps should unproblematic handle -25°C (air to air), and provide 4-5kWh of heat for each kWh of power used.
None as far as I can tell. Some people I know here in Norway turn off the heat pump when the outside temperature is below -25°C, but those pumps were installed some years ago.
Good point, I did not think about the fact that the effeciency went down. But it seems to me (as a noob) that modern heat pumps specialising in low temperature conditions still can get around 2.5 at -25°, which gives you more than 10kWh of heating at 5kW, which is quite a lot.
Solar panels produce the most power on cold winter days. The 'rated power' is for 20 degrees ambient at full (90 degrees, no cloud) incidence at sea level.
"5kW of panels don't produce 5kW in winter" -> there is no 'time' factor in there.
What you could say is that solar panels in the winter do not produce the same amount of power in an average day as they do in the summer due to the shorter day and the bigger chance of occlusion as well as the longer path the suns rays have to travel through the atmosphere.
That really depends on how far north you live. Where I live a good winter day's production is ~10% of a good summer day's. (Also depends on the orientation, but it's never even close, let alone more)
Yes, in locations like that you will have to use some other solution for those periods. Maybe wind power. Battery storage will not last long enough unless you have an absolutely massive setup that would not be cost effective the rest of the year.
I had 48KWh worth of storage, 2500 W worth of wind and another 5000 W worth of solar. This was in Northern Ontario. Until we added the windmill we fairly regularly needed the generator, after we added the windmill the generator just sat there gathering dust.
Could you say something about the analysis you did to decide that wind was going to be useful for you? I'm interested but I don't really don't have a good sense for how cost effective a wind turbine is or how to evaluate a site.
The Canadian meteorology department puts out pretty useful stats, and I dropped in on a couple of people in the neighborhood that had windmills up to see what kind of windspeeds they were seeing and how long on average their machines stood still.
This was a major factor in designing the machine the way I did, variable pitch is a lot more work but a machine like that will start up far earlier than a fixed pitch machine. It also had its effect on that stator, which I made with the laminates at a slant over 1/3rd magnet width, which reduced cogging to nearly nothing. This is a huge factor in starting up a direct drive machine.
Yeah, some people had problems with all-in-one battery systems in their homes that were AC coupled to their solar here in Australia over some weather disasters where there were prolonged outages for that reason.
I’d quite like a battery system, I think I’d DIY (well, design the system but here you need a licensed electrician to wire up the AC/grid connect side) using Victron equipment. I have a 5 kW solar system already with a AC inverter which I can keep, so I would probably use a 5000KVA inverter-charger (Multiplus-II), but then I’d add another 1.5kW or so of solar that is directly DC coupled to the batteries and the DC side of the inverter-charger through a separate DC MPPT tracker.
So the DC coupled solar would be enough to kick-start the system to get the AC side back on after a bit if the grid was out and the batteries were depleted overnight.
What I did in Canada was to dig a bunker into the side of a hill near the house. That solved both the frost and any fluid issues in one go. It was a bit of work though to get that all done.
The problem with holes in the ground for storage of things like batteries is that... they're holes in the ground. The ground, as a general guideline, actively dislikes holes in it and strives to fill them in whatever way possible. Liquid rolling in, soil creep, debris blowing past and building up, it doesn't matter - given a long enough time, a hole in the ground won't exist anymore.
You can build a hole that will hold up to this sort of stuff for a while, but that tends to be expensive - underground concrete work is neither cheap nor easy, and given the number of people injured in trench collapses who do it for a living, a serious underground hole isn't a good DIY project either.
That just leaves the maintenance, which also sucks for a hole in the ground. Anything you have to do on the batteries is easier with them on or above the ground, instead of underground in a hole. For lithium, it's fairly low maintenance but you may have to replace some BMS boards every now and then, manually check balance, etc, and for lead it's water every few months, unless you go with sealed, which are "maintenance free," but also "maintenance and status check impossible," so you really just set them and run them to failure - you can't monitor condition like you can with flooded.
It's the sort of solution that, technically, would work - it just ends up being radically more expensive and a hassle than it's remotely worth. Think "Spending $5000 to save $20/yr" sort of thing.
You see the same trend with things like the complex solar trackers that were common in the 80s and early 90s. With the cost of panels, optimizing every bit of power from them was critical, so spending an awful lot of money on support infrastructure to optimize $10/W panel production made quite a bit of practical and financial sense.
Today, with panels at $0.50/W, very few people bother with trackers anymore (for off grid installs). Most things you could improve with a tracker, you can improve with less effort and less money by just hanging more panels. Bonus: With more panels, you get more production on cloudy days when panel orientation doesn't matter (because the sky is more or less evenly lit).
I've got south facing, east facing, and west facing panels on my office, of two different brands, all fed into a single MPPT charge controller input (I do have some blocking diodes to prevent backfeeding a shaded string, though). It's not nearly as "efficient" as some other options, but it's a whole lot cheaper, and gives me more power on the low cloud days that are the rough ones. The rest of the year, I have so much power out there that I'm demand limited, not supply limited (actually, inverter limited - if I added some 48VDC loads, I could use another 5kWh/day easily).
I think you are way overselling the difficulty of digging a hole in the ground. Go to any grave yard- full of sealed coffins, all below the frost line.
Get a plastic storage box, drill holes for cables and seal them with caulk. Put inside a treated lumber box for extra crushing resistance. Run cables through metal conduits to avoid mice and moles chewing on them.
Rent a backhoe, and you are done in half an afternoon.
All of that said, I dont know that I would actually go that far- you avoid the battery freezing, but then you get to worry about it cooking. For an off-grid cabin that isn't constantly heated in winter, it isn't the worst idea.
I dug a hole in the ground to act as a makeshift cellar. About 1 meter cubed, dug it with a shovel, poured gravel as a floor with a French drain sunk in it, lined the walls with breezeblock, made a lid of plywood and foam insulation board. Erected a kind of tent on top to keep the rain out.
No issues so far, two years in. It’s not terribly cool in the hottest days of summer and does require a small heater if I want to keep it above freezing through winter, but in terms of being difficult or expensive to build, not at all.
> actually, inverter limited - if I added some 48VDC loads
I know it’s only lighting as a load, but I’ve heard standard LED light bulbs will happily run as low as 36VDC, as they chop the voltage down to that level anyway.
It makes me wonder how many “120VAC” devices with switch mode power supplies could be plugged into 48VDC without any thought at all. And not just electronics like a laptop or non-plasma flatscreen, but everything is moving in this direction:
Like… what’s my Variable Frequency Drive “inverter” refrigerator motor voltage really running at? In theory it should happily run off 120VDC at least. Don’t do that, but somewhere under 110VDC should work fine. And it’s inherently soft start and easier on one’s low voltage wiring than an on/off duty cycle fridge.
Most modern switch mode power supplies will run on DC, but you really, really want to jack the input DC up high unless you're a fan of replacing bridge rectifier diodes and other input wiring.
Active power factor correction circuitry will have a fit, but... eh, whatever. It's DC now, nobody cares!
A 120VRMS AC signal peaks around 170V, and most (not all, but most...) switch mode power supplies are auto ranging, so they'll tolerate from about 100VRMS to about 250VRMS - which is near 400V peak. If you can get 300+VDC into them, they'll be quite happy, but the boost converters to do that are a pain to find, and by the time you build one, you may as well just get a 120VAC inverter and call it good.
The main thing to be concerned about, and the reason to jack the input voltages about as high as you can, is that almost every switch mode power supply has a full bridge rectifier on the input side. From an AC input source, each diode has a 50% duty cycle. Put DC on it, now two diodes are at 100% duty cycle, two are at 0% duty cycle. How much overhead was there in the system? Well... you'll find out! However, a system capable of running and not overloading the diodes at 50% duty cycle at ~100VAC should be totally fine in terms of diode heating at 300VDC - just, perhaps not at 100VDC.
I never considered the diode duty cycles. If nameplate was 120-240VAC (my TV says 120 but the p/s PCB inside says 100-240…) I’d like to think each would have the overhead to handle under 100VDC, but maybe I’m underestimating the impact of higher current. Edit: you’re right that the “hot” ones will run twice as hot with their 0.6V or whatever drop.
All I could think about was the (potential) improvements on capacitor lifespan since they won’t have to smoothen, but wasn’t sure if their electrolyte could still heat/dry if it was actually the connection to power that makes them hot.
Thinking further, an internal fuse might blow with the (expectedly) larger current draw at 48V.
And yeah on input wiring, you’re pulling more current at 48V.
Welcome to the world of powering AC equipment on DC. It can be done, surprisingly often.
But as soon as you've got some stuff that requires an inverter, you may as well just light the inverter up for everything. I've got the equipment to do a separate, lithium-backed "DC rail" in my office that would be around 40V, and then buck it down for various devices, run my routers direct on it, and... I've never gotten around to doing it, because until literally everything is on that, I'd still have to run the inverter for things like system sleep (I sleep most of my computers overnight). I'm fiddling watts around and it's just not worth it unless I can actually shut the inverter down entirely. Unfortunately, boosting up to 300VDC isn't cheap or easy.
I've wondered if you could run some of that stuff straight off solar during good sun, but I've never really wanted to subject my computers to that sort of abuse.
> I'm fiddling watts around and it's just not worth it unless I can actually shut the inverter down entirely.
That’s where I’m coming from: trying to convince a family member to setup a DC system so the inverter can stay in sleep mode during evening/overnight, because the efficiency is horrendous at small loads. it’s really academic in kWh savings per day, but it saves you the most when sunlight’s the least and reduces battery cycling. But if you’re running an office, the inverter is pretty much running a good load or off, I think.
Could you insulate the batteries to reduce the heating demand? Instead of heating the entire cabin just heat the battery compartment, and only to the minimum necessary to keep them from being damaged (plus a margin for safety).
Maybe even just toss them in an old discarded deep freeze? You could even have one battery in there that is disconnected from the rest of the system so it can be used to jump start the system if it ever gets fully discharged.
An old deep freeze is probably not sufficient, but packing them into a thick layer of insulation should be fine for the winter. The insulation would have to completely enclose them though, including the bottom.
Maybe best to have them sit on a thick layer of insulation on the bottom, and a box that can be removed during the summer months so the batteries don't overheat.
Another a bit weird idea would be to somehow put them next to a compost heap, which produces low temperature heat for a long time (years) including during the winter.
You can insulate them to reduce heating demand, and it will help to an extent (undo that before summer to avoid cooking them), but for an unattended system, it's never going to work out very well. If the system is a year round cabin, the solution is easy enough - keep them in the heated space (which you'll have propane/kerosene/biomass heaters for), and it's not a real problem. But unattended stuff... you really just need to plan for something that can tolerate bitter cold without damage. Or to seriously overpanel the system, 10x+ what you need for summer use, and hope they produce something.
I think most people underestimate just how much delta in production there can be on solar. My house array is grid tied, 16kW, a bit weird looking (mostly east-west panels, designed for post net metering). On a really good, cool, clear, windy spring day, I can produce about 105kWh out of the system from sunup to sundown.
On a really bad, low, grey, winter day, that same system produces about 2kWh. It's literally a factor of 50 difference. And we can get several days of that in a row. I have a backup generator that I use for my office on weeks like that (separate, off-grid system).
"Winter, electric heat on solar" is a fairly good filter for those who have read about solar or pondered it, and those who have a few years of it under their belt. The second group are the ones who've tried it, discovered just how horribly it doesn't work, and are trying to convince the first group that, no, really, insert well worn idea here really doesn't fix the problems with it.
I guarantee if it were easy, people would be doing it. That you won't find any serious off grid system doing electric battery heating is because it doesn't work.
Adding on to this the energy usage of my multi-head heat pump system has been quite surprising when it drops below freezing. I have a Mitsubishi unit which is rated down to something like -15F however below 32F it uses enough energy to get pretty close with fossil fuels on price. It looks like I will have to add on to my 11.85kW solar system to be able to get the projected energy use throughout the year. Winter time will have a significant deficit and summer overproduction will make some of it back but not all. I am also investing in air sealing and additional insulation.
Have you priced LTO? They're rather staggeringly expensive for their capacity. The cycle life is excellent, but they excel in very high C-rate applications (10C-20C), which is the opposite of what you need for off-grid systems. If an off grid system is getting anywhere near C/10 discharge rates, you're going to be in the dark awfully soon.
It's old tech, it's boring, but it works fine... flooded lead acid. Don't fully discharge it in the winter, and they won't freeze. They'll cycle just fine in the cold. Well tested, proven, and unless you're full time living and heating an interior space that can be lithium-friendly, they're the right option. Disconnect all the loads and run them on float in the winter with a high, vertical, south facing panel (obviously swap that if you're in the southern hemisphere), and they'll do just fine.
Yeah, lead wins hands down. This is a few years out of date now, but when speccing out my system I did a bit of analysis of battery types. We went with OPzS, and so far, so good.
Recycled Lithium Ion is much cheaper still, but more risky (and less maintenance). You'll have to do some pretty fanatic inbound QA to determine whether all your cells are safe to use. but if you do that and fuse your cells individually you should be able to make that work.
>> 1) These Controller+Inverter combo units require a battery to turn on
Which is why you want to install disconnects between your battery bank and the electronics. In a worst-case scenario of total discharge you can then bypass the dead batteries, hook the control electronics up to car batteries if necessary (be careful about voltages) and perform some diagnostics or at least read the logs of what went wrong. But the controller+inverter should be running if supplied with voltage from solar/wind/generator regardless of how the batteries are doing.
> But the controller+inverter should be running if supplied with voltage from solar/wind/generator regardless of how the batteries are doing.
Most of them don't operate that way. They need the battery bank connected first, and run off the battery bank side, while controlling the panel side.
Some may tolerate that sort of recovery from deep discharge, but it's not a safe bet, and some controllers are pretty clear that if you connect the input side before the batteries, you'll damage the controller.
A dumb PWM controller stands a better chance of doing this, but something like an MPPT controller, unless it's explicitly designed to fail into a PWM configuration at low battery voltage, won't - they need power to drive the buck converter circuitry (the controlling ICs and oscillators and such) in order to get power out of the panels.
Have you considered a small backup generator? If it exists I would go with one that is propane powered. Propane goes to -50° before freezing so unless you live in Alaska, you have quite some margin here.
You need to manually set the low voltage disconnect so that your batteries bms does not go into safety mode. then you won't have the first problem you stated.
What you need is more insulation. I've tested that battery and the internal heaters work great, but you should put it somewhere where the heat that is created stays in the battery.
You can dig a 2 meter deep hole and store the batteries there. It won't freeze during the winder if left turned off. If you plan to turn it on on the holes, you might need to plan for heat dissipation though.
LiFePO4 batteries can be stored and used below freezing, they just shouldn't be charged. All you have to do is turn the system off when you're not there.
Marketing. I would take everything on this website with a grain of salt. Take it from someone who has actually built an off-grid system, one that is relied upon for 24/7/365 living rather than mere vacation cottage.
For example: OP re lead-acid battery options:
"Heavy, cheap, easy to use and they work! Typically will last about 3-5 years. Slower charge rates than lithium, much heavier, and they cost way more in the long run."
That is just plain incorrect. Lead-acid batteries regularly last a decade or more and are far cheaper than any lithium option at a given capacity. Look at nearly every 12v car or boat battery. You don't see those being replaced every 3-5 years. It is old reliable tech that just works. And, at a given price point, they can charge faster than lithium too.
The downside of lead-acid? There is little profit to make in selling them. All the patents have expired. They don't need software to control them. They are mature, centuries-old technology. A thousand companies are making lead-acid batteries and you can get them cheap. They weigh more, but for residential installation that isn't an issue.
The upside? Whereas lithium packs are a nightmare to recycle, lead-acid batteries hook into an established and profitable recycling system. They are the greener alternative to anything containing lithium.
> Look at nearly every 12v car or boat battery. You don't see those being replaced every 3-5 years. It is old reliable tech that just works.
I actually do see this all of the time. In decades of owning multiple cars I've found the batteries tend to fail so regularly at about the 5 year mark that you could set a watch to it.
They are easy to find and inexpensive to replace, but they absolutely do have a limited lifespan.
I would love to have found that magical car battery that doesn't die after 5 years or so. But the real comedy is that my EV is required to have one of them independent of all the lithium batteries, and if it discharges/fails, it's a whole fan dance to get into the car.
I've never jumped a full EV, but I have had to jump a couple hybrids after their 12v batteries ran flat. Can you not get to the 12v battery using a mechanical key? Any 12v jumpstart kit should provide enough voltage to activate the solenoid and get everything online.
Unsealed lead batteries that go through proper solution maintenance can definitely last decades - I have a forklift that keeps almost 1/2 its original charge and it was made in 1982. but I have flushed and cleaned the cells a few times and keep track of the pH when I top them off.
I lived 10 years off grid in vans and rvs, and now I mine bitcoin and charge my teslas with offgrid solar. I have built systems with every chemistry, even lithium polymer and LTO. And FLA and AGM. I have a lot of experience in this realm. It does not sound like youv'e seen my videos before.
Lithium packs are not a nightmare to recycle anymore. There are huge corporations fighting to recycle them now, and the tech has improved a lot. I could not say this two years ago. Lead acid is easier to recycle, but the cycle life of those packs, and sulfation you have to deal with, make them horrible for the environment. Cycling them deeply kills them fast, even the expensive ones. If you do not cycle them deeply, FLA will last for decades, but will cost a lot of money , space etc. And you need to maintain them. Lithium ion chemistries such as LiFePO4 are far superior.
I think you need to get your hands on some cells and actually build a pack. Test the coulombic efficiency and usable capacity at various temperatures and you will be blown away. And you will save a ton of money over lead acid. Lead acid is very expensive, and I would make a lot more money if I sold them. I also do not sell anything on that website, it only has affiliate links. I am not on any sponsorship contracts or have loyalty to any company. Most of my review videos are me bashing design errors and various solar companies. I do not think you have seen my videos, going by your comment. It is a little bit cringy, unfortunately.
The OP, Will Prowse knows what he’s talking about. He lives off the grid and meticulously documents all of his testing and research. When I was new to solar to battery power storage, I learned everything I needed to know from his website and videos to build my own off the grid system. Check out his YouTube channel.
Will Prowse here. Are you kidding me? Those lead acids are kept at a high state of charge and not deeply discharged. Sure some expensive FLA can last much longer, but they are garbage. The coulombic efficiency is horrible. The internal resistance is awful. If I sold lead acid batteries, I would make way more money. You have no clue what you are talking about. And yes, when used for solar and deeply discharged, your lucky to get 3-5 years.
Tell that to my 12 year-old battery bank powering my family house (solar with diesel backup charge). It is a pack of deep cycle lead-acids that have served me very well. Of course they are watched and maintained regularly, and rarely ever dip below 75%.
The only use case I've ever seen for lithium off-grid is for people who want to squeeze their entire rig into a closet or basement corner. And nobody ever talks about what to do with those batteries once they finally die. My packs will be easily recycled.
See, exactly proves my point. DOD is only 25%. If you do not cycle them much, you can make a lead acid last for years no problem. If you are doing 100% DOD, and do not with to deal with maintenance, and wish to have high coulombic efficiency, lithium is far better.
Volumetric density is a side benefit of lithium. We use it for coulombic efficiency, low voltage sag, high cycle life (much higher than lead acid, regardless of cycling bandwidth), usable capacity at low temperatures (much higher than lead acid! People always get this wrong), and higher specific energy. And lead acid sulfation and shorted cells require recycling. You can safely use a lifepo4 pack for years after degradation occurs. Lead acid is easier to recycle, but lithium ion recycling companies are dominating the space now. It is not like it was 3 years ago. Times are changing and there is no way anyone wants to throw out cobalt from a pack. LFP is much easier to recycle than cobalt based chemistries as well.
Solar2 == willprowseiv? Brand new account responding as such, at least.
Which production lithium ion recycling companies are "dominating the space" and actually recycling more than test quantities of cells? Apparently I've missed that in the past few years - links to them?
Over the years, I've generally made the observation that those who really slam lead acid for energy storage use seem to have been nowhere near a modern lead acid datasheet from the last 20 years, and that seems to be the case here as well. They also tend to make assorted arguments in the context of off-grid power that don't reflect the realities of off-grid power systems in annual use.
The mid-range Trojan Solar Premium line (my office runs an older version of this, the T105-RE and I'm five years of daily cycling in with what seem to be entirely healthy batteries still) datasheet [0] shows a 3500 cycle life at 30% DoD, which is 10 years of daily cycling use. However, depending on loads, panels, and how you use the place, you'll typically see far shallower cycles in the spring/summer/fall, and then some deeper cycles in the winter months. So you can average it out - a single 80% discharge isn't going to have a huge impact on longevity, just don't do it all day, every day. If you've got enough panel area to recover a low battery bank in a good day or so of sun (generally recommended for off-grid), you'll have enough panel area to ride through daytime loads most of the year without really bothering the battery pack either.
The Solar Industrial line [1] is rated 3500 cycles at 50% DoD daily cycling, and about 6250 at 30% DoD. Good luck finding them, though.
They also, as has been discussed elsewhere here, don't need heating in the winter to be able to charge safely. I generally don't like charging lithium below about 45F, and even that would be a low C-rate. Not having to heat lead makes winter an awful lot easier.
As far as the rest of your claims... they mostly don't matter for a typical off-grid power system, which is the general context of this thread.
Coulombic efficiency for lead varies rather significantly depending on where in the state of charge, and it's not really reasonable to discuss "average" numbers for lead. Once you're full, up in absorb, the CE is quite poor, as it's gassing, but that's also required to mix the electrolyte and prevent stratification, so it's still doing something useful. However, the times when it matters - cold, dark winter months, if you're running partial state of charge cycling (which the modern carbon additives allow without the problems of hard sulfation), the CE during charging is quite good - near 100%, as long as you're below gassing. So when CE matters, when you're power limited, it's perfectly reasonable, and when it doesn't matter, when you have a surplus of power, it's poor. I don't particularly mind that.
As far as internal resistance goes, it's certainly far worse than lithium, but at typical off-grid C/20, C/8 type rates, it just doesn't matter that much. Nobody is asking deep cycle off grid lead to deliver starting amps for a tractor, and it won't do it, because it's a substantially different internal design than a starting battery (which have far lower internal resistance - go measure one sometime, it's pretty impressive just how low IR on a warm car battery is).
And my 48V/225Ah bank ran me $1400 about 5 years ago, and is about halfway through service life, or perhaps a bit less than half. To do that on a lithium chemistry would be quite a bit more expensive.
Plus, flooded lead acid lacks the energy density to do anything terribly exciting, as long as you give hydrogen generated from charging an "up and out" path. I consider this a feature for stationary storage.
And they're almost entirely recyclable (and actively recycled). It's a quite circular economy in the lead acid battery space.
Different chemistries have their places. For a somewhat overpaneled off-grid system in daily use, lead acid is still an absolutely reasonable chemistry (as quite a few people here are still observing).
I can believe that lead-acid batteries in a thermally-regulated and immobile location would have a longevity advantage. But what magic dance are you doing to get car batteries to last longer than 5 years? I - and my parents, and seemingly everyone else I know - absolutely do seem to have to replace them at just about exactly that interval.
That's not to say they aren't filling their role in a totally reasonable way, I'm just really curious how you're getting more life out of them than the rest of us.
"And, at a given price point, they can charge faster than lithium too."
Please elaborate; I have no idea what you're talking about here.
My deep-cycle RV batteries are nearly dead and I'm going to spend the $$$ to replace them w/ a lithium battery partially because of lithium's faster charging. At peak solar season, I only get about 3 to 4 hours of good sunlight on my forested property so I need batteries that charge relatively quickly.
Not sure if this is a troll post. Your lead acid comment is sImPlY iNcOrReCt, and you clearly don't know the owner of the website as he is a dude who runs his YouTube channel in a very transparent way.
That's interesting. Winters are cold where I'm originally from, and car batteries get replaced more frequently than once in 10 years. Where are you from? Your experience is very different.
Northern Alberta. Currently -30c. The 8yo battery in my car started my engine just fine this morning, with the help of my block and battery heaters that ran all night. I think people in the north might have longer battery life because of the harsh conditions. We probably spend more time/money on maintenance of vehicles precisely because we need them to start when very cold. I have noticed a deeper voltage drop when starting my car this winter. The battery might well be on its last legs but so long as it is still working I'll hold off replacing it. (I do carry a jumpstart kit in my trunk, right beside the snow chains.)
What actually happened to your car battery to cause you to replace it? Did you do anything to fix it? Did you ever maintain it? Did you replace the fluid? Or did you just drive your car every day and then replaced the battery when the mechanic told you it was broken? It is normally cheaper to replace a standard car battery than attempt to maintain and fix it (100-200$) but in an off-grid situation many thousands of dollars are at stake, which makes maintenance and repair more practical than replacement.
Car batteries these days are sealed, so you don't really have much opportunity to replace their acid. A regularly-driven car isn't deep-cycling its battery, so I'm not sure what else you'd do to maintain it.
You test it regularly and hook it up to a good desulfator/maintainer when needed. A sealed battery might be acceptable for a car, if the owner has the money to replace it regularly, but not in an off-grid/residential situation.
It would have helped to do a more benevolent analysis/interpretation here. For example, you mentioned yourself that lead batteries need checking, change of fluids, etc, most of which noone does.
Will Prose seems like a really great person. If you’re interested in what you see on this site, check out his YouTube channel: https://youtube.com/c/WillProwse
The problem with him, and people like him on YouTube, is that about 90% of what they say is fine, and 10% ranges from "iffy" to "This is a good way to burn your house down - at some unknown point in the future." The average viewer of that sort of material can't tell the difference, and by the time you can, you're not in need of handwaving entry level information, because you can read the design documents, spec sheets, NEC, and do things yourself.
YouTube is simply the wrong medium to try to teach detailed, "can kill you" things like electricity. It's especially wrong when you try to make it about personality, humor, etc moreso than hard technical truths.
sounds a bit gate-keepy to me. People tell me that I shouldn't repair my own car for similar reasons. Instead I should go to the OEM and have it serviced there for 1000,- a pop. This assures I'm getting genuine OEM branded parts with a 800% profit margin while also reducing the time spent on diagnosing the issue because now whole modules get replaced since cost of human labor is expensive. If I would heed that advise, I'd still have no clue about how a modern diesel engine worked, how to reverse and flash a new ECU firmware, how to find and fix any problem without a mechanic ripping me off, or generally engage in things that (in the eyes of the vendor) are "very dangerous" to myself, my family, or others.
Yet I still make this choice because the alternative is a "John Deer no right to repair" future where we're ruled by chuckeducks and awful people who can't help but quote "rules and regulations" or can't wait to be up in everyone's shit. There is no way I could be convinced otherwise because this is the nature of those who fiddle and tinker in the first place. I'm sure many of the viewers on this channel think likewise because it's not about safety but about my own freedom to spend my weekends in the garage building something and being rewarded with self reliance. And also the freedom to make mistakes big enough to kill myself by accident without somebody going "uhm well ack-shually".
He has a point, but there is a thing you can do to offset some of this: read all of the comments. Plenty of times there will be someone in the comments pointing out what's wrong in the videos.
The problem with Lithium Ion installations of any size is that the batteries are inherently dangerous and mistakes can easily set you back more than you saved on the whole thing. Unlike say your car where as long as you stay away from suspension, brakes and steering the worst that could happen is that you end up stranded by the road side.
Another issue is that when it goes wrong with Lithium Ion it can go wrong fast and it isn't easy, or sometimes even possible, to stop a thermal runaway once it gets going, especially with densely packed cells, besides the fact that you likely won't be watching your batteries 24x7.
There are some people on youtube that advocate for extremely unsafe practices (Jehu Garcia, for instance) and that have a huge following, so Will Prowse is certainly not the worst that you could run into there. It would also be good if he indicated more clearly what his sponsorship relations are and how that relates to the advice that he is giving, quite a few of his videos feel like thinly disguised ads.
very much with you and GP on this. the route I personally take is to learn with small trials and error of what comments and advise is good and what is silly or outright dangerous. Places I frequent for such advise though aren't YT videos but forums where it's easy for others to call out silly ideas (which isn't always the case on YT). YT is at best a gateway to deeper content such as explosion-charts, repair and maintenance manuals, etc. I think batteries here are not too different than breaks, steering or suspension (all components I've grown comfortable to touch although not on my very first DYI project but years into messing and learning about the same vehicle).
It's clear that Will has rubbed you the wrong way by his responses in this thread, but when you call out someone's professional conduct linked to their business in public forum words matter.
Lead generation into Amazon affiliate links are not a sponsorships.
His business makes money off of affiliate links, not sponsorships. There is a difference. Both could carry a bias, but a sponsorship is significantly more suspect than an Amazon affiliate program. For another example, see Wirecutter, also funded by affiliate links, but (until recently post NYT buy out issues) a pretty respected review site. Personally, I generally wouldn't buy anything off the recommendation of a YouTube sponsorship. I would consider buying something that had an affiliate link.
Feel free to let me know if I missed a sponsorship disclaimer.
Here is the disclaimer his website.
Prowse Publications LLC (www.mobile-solarpower.com) is a participant in the Amazon Services LLC Associates Program,
an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com
I make a commission for sales made through affiliate links posted on this website
I've zero objections with people learning about power systems and such.
My objection is with people learning it from YouTube, because the ratio of "good, safe, correct information" to "absolute crap" is horrible, and until you're quite solid in the field, there are people very confidently spouting exceedingly wrong and dangerous information (tip: If you ever see anyone soldering to an 18650, assume everything else they're doing is wrong as well, because that's such a huge violation of every manufacturer datasheet - it dumps radically more thermal energy into the cell and plastic separator than they're designed for).
There are plenty of better sources for information on how to do things energy related than YouTube.
"It's especially wrong when you try to make it about personality, humor, etc moreso than hard technical truths."
Have you spent any time watching Will's videos? Your quote doesn't match up at all with what I've seen at all. I found his videos dry, technical, and pretty good with regard to safety.
That's an absolutely absurd characterization of both YouTube and actual teaching.
YouTube is dominantly entertainment/personality based "edutainment" at best, based on what seems to percolate to the top and be promoted. There's zero feedback outside comments (standard warnings about comment sections apply here).
The right way to teach complex subjects is a more interactive process with hands on material/learning/actually solving the problems yourself. In the case of solar and energy systems, you can do this, but if you don't have some basic EE background, it would be wise to go get that first before listening to some slick talking huckster selling their wares. WHY do we size wires the way we do (either for temperature limits or for voltage drop, depending on the application)? What's wrong with a 5000W 12V inverter (500A or so, and the I^2 components of resistive losses, paired with the voltage drop from those)?
I don't think a human lecturing blindly into the void optimizing for "engagement" (whatever metrics those are based on this week) can competently teach any real detailed material, no. That doesn't mean that people can't teach complex material. It just means YouTube is not the place or medium for it.
A lot of educational content on YouTube is made by people who have no idea (or interest in) how to optimize for engagement. I'd be willing to bet there is fairly competent basic EE instruction on YouTube that includes lab instructions, working with simulations, problems, and pulling in other exogenous resources to aid in understanding. Its not just a wasteland of pop science like Veritasium, et al.
1. A theoretical space for someone with good ideas and good intentions to share those with the world.
2. The actual experience that viewers will have on YouTube if they were to open it today.
1. and 2. would be almost diametrically opposed these days. If YouTube provided ways for viewers to honestly and fairly discover, rate, filter, and share videos and channels, then the people in case 2 would be able to reliably find the people in case 1. And if YouTube didn't force video makers to pervert their personality and format into algorithm-pleasing parodies, then people in case 1. could continue to produce the content they actually want to produce as long as they were able to. But it's not possible today.
YouTube encourages generating content that rates well, i.e. is entertaining. I agree that learning should be fun, but I don't want to learn about life threating topics from videos that are designed foremost to be entertaining.
There is plenty of non-entertaining yet informative and detailed educational content on YouTube. The "entertaining" videos are usually just a gateway to more dry and traditional lectures and courses that are provided by universities and other content generators that see YouTube as a general resource and not an income stream.
This is the dumbest take I've read in a long time. From him I've learned which lifepo4 batteries won't burn my house down, proper wiring for stuff, etc. I've got a 144ah battery pack sitting right next to me as I type this I built from learning from him. Are you sure your comment isn't about the youtuber Electricboom?
I rebuilt large (500Wh) lithium ebike batteries professionally and shipped them around North America for a couple years, and have torn down more than my fair share of ebike and tool batteries for analysis.
I've yet to see a "YouTube Trained" pack build that I would be remotely comfortable leaving unattended in my house. Though LFP is an awful lot more forgiving than a mix of random recycled 18650s of unknown chemistry, service life, and internal damage history that makes up the bulk of that stuff.
If you've got some good high res shots of the build process, I'd happily take a look and see what I think of it. My standards of comparison are the professionally built packs I've torn down for analysis and often enough rebuilt for people.
As for who my comment is about, honestly, I apply it generally to that entire class of person on YouTube no matter who they are. I know solar, and off grid solar, fairly well (with a focus on flooded lead acid). I know lithium fairly well, having done quite extensive work on them. In areas I know well, most of the people showing stuff off or trying to teach other people hit the 90/10 split, and as this is a topic of conversation in the quiet off grid backwaters circles I frequent, other people usually agree about which 10% is the problem.
Therefore I'm happy to ignore that entire class of person and go do something useful. It's not that education can't be funny, it's that when "personality" and "laughs" and "BIG O FACE I NEARLY BLEW MYSELF UP" style thumbnails are what matters, the really deep (and often quite important) technical details get lost in all that.
I was giving you the benefit of doubt, but this comment shows that you've never watched any of Will's video and you are just painting with a very broad brush.
He's the kind of Youtuber that keeps repeating that you should place a low temp sensor on your cells, not the kind doing sketchy spot weld on old 18650s.
I have seen enough of his videos to know that he can be spectacularly wrong (dangerously so) about some of his stuff and if you are not already very knowledgeable about this then you may well end up following some very bad advice.
This guy has far more practical experience and seems to be less error prone, and also does not shy away from showing when he gets it wrong, which is often far more valuable than a polished and edited video:
Sure, but I will have to go through a couple of months worth of youtube history, I was binge watching anything about Lithium Ion when I was working on this:
As a result I have a very long article on Lithium Ion battery safety and pack construction in the works, but exactly for the reasons the GGP lists I'm pretty careful about releasing that, I want to triple check everything before putting it out there to ensure that the net result is a positive one.
Also: I don't like the youtube format for stuff like this. It would be far better to have these things as blog posts rather than as videos, that would make them much more searchable and easier to annotate.
But just to give you two memorable items: at some point Will shows himself working with naked steel tools on a massive, fully charged, unfused battery pack. Just one wrong move or a dropped tool and the carnage would be substantial. That shows to me that he may have good theoretical knowledge but doesn't really know all that much about working with this stuff in practice and how to do so safely. In another video there is a whole slew of balance wires coming out of a pack, crossing and recrossing with abandon. Balance wires are usually not fused, the wires rubbing means that if that installation were for long term use that eventually the balance wires would short out and if you're lucky it would just result in a balance wire evaporating, if you're unlucky it would start a fire right next to a massive Li Ion battery, something that you really don't want to do because of their thermal sensitivity. The risk is that the whole pack would ignite and good luck putting that out.
I went to the ETS in Amsterdam, a school for electrical technicians, mid level. The one thing that was drilled into us over and over again during the practical parts of that education is that in the electrical world there are young safe technicians and young sloppy technicians, but there are no old sloppy technicians.
Just because I am young doesn't mean anything. I know what I'm talking about. I started coding and building robots when I was 13, and circuit design at 15. Solar power is dead simple.
Yeah I can work with raw terminals because I don't make silly mistakes. I've been working with low voltage DC for decades. Most of the systems I throw together are for educational use. Those balance wires were probably a rapid prototype pack where I was testing something. I know what I'm doing and how it works. And wow you're so dramatic about the balance wires why don't you criticize the companies that offer their pack configurations in ways that you complain about? There are many companies that throw these packs together and sell them to unsuspecting people, and you are giving me a hard time when making a quick pack to educate or test something? Give me a break
> I started coding and building robots when I was 13, and circuit design at 15. Solar power is dead simple.
Similar, but I would _never_ play fast and loose around batteries of those sizes just because I felt like I won't make "silly mistakes". Everyone, even professionals who have been doing dangerous work for decades, make silly mistakes. That's why professionals don't fuck around. One wrong move with large lithium cells and you've got a massive jet of fire in your workshop that can't be put out.
Similarly, I'm a woodworker and while I feel like I know what I'm doing around a table saw these days, I _always_ make sure to have my adrenaline pumping when making cuts. I Point and Call my safety checklist every single time. I wear my safety glasses for even the simplest cuts off the table saw. And guess what? It has saved my bacon. It's the simple, mundane, "I don't make silly mistakes" days that cost you.
> And wow you're so dramatic
It's better etiquette to address the content of a comment rather than lob insults against the commenter. The former is less argumentative and can be more informative. Strive to enlighten and inform. Nobody learns anything useful from phrases like "you're so dramatic", "Give me a break", "you are giving me a hard time", "Are you kidding me?", "You have no clue what you are talking about", etc.
> Yeah I can work with raw terminals because I don't make silly mistakes.
This attitude will cost you dearly and is exactly the difference between being a responsible educator and someone who probably should pause to ask themselves if they are on the right track.
You are setting a bad example and many thousands of people will follow in your tracks adopting your very unsafe practices as though that's the way to do it. Some of them will end up hurt.
It pretty much validates my earlier assessment but I'm actually a bit surprised that you would come out to make it so obvious.
> Those balance wires were probably a rapid prototype pack where I was testing something.
Yes, but that's not what matters here. What matters here is that people see you work and believe that's the way it's done. With authority comes responsibility.
> And wow you're so dramatic about the balance wires why don't you criticize the companies that offer their pack configurations in ways that you complain about?
That's whataboutism. We're discussing you, not some company. These tricks don't really work on HN.
> There are many companies that throw these packs together and sell them to unsuspecting people, and you are giving me a hard time when making a quick pack to educate or test something?
Yes, I'm giving you a hard time because you are at the same time claiming to be educating and you are advocating unsafe practices while doing so.
> Give me a break
Unlikely, and after this comment far less so.
But thank you for clearing up any ambiguity about where your feeling about responsibility lies.
Wait, you do realize I am still wearing safety glasses and following basic safety precautions, which I state over and over again. I sound like a broken record repeating this stuff. I can work with raw terminals, because I know what I am doing, and I follow basic safety protocols every single time. That is why I am not dead. If I was wrong, I would be dead. I cover safety in every video.
And yes, I hope people follow my advice more than the other channels. People on this website are suggesting people use cobalt based chemistries that have dangerous thermal runaway reactions, from recycled products, which is dangerous. And then my channel complains constantly on the importance of low temp charging disconnect, OCPD, high voltage and so much more. What am I doing wrong here? How you read my comment, makes me realize that you never did watch my videos. You really have no clue what you are talking about. Using recycled NMC cells will burn your house down, plain and simple. And people in this group who think they know what they are talking about are recommending to do that instead? What???
Yes, with authority comes responsibility, and the only reason people follow me is because I cover every single detail, and I substantiate my claims with relevant literature in the lithium ion space.
I had commented to this affect on his channel and my comment was removed. Same with other channels where people are drilling without hand and eye protection.
That's really bad because your comment would at least give people a chance to calibrate the degree to which they should trust this stuff. Any video that aims to be instructional should at least spend some time on the safety aspects of what they are doing.
I usually always wear eye protection. YouTube deletes comments constantly. And leaves the spam comments. Have you not used YouTube in the last ten years? I can't stand it
I can't tell how Youtube decides what to keep and what to remove or if my comment was removed by a bot or by the channel owner. On a traditional forum a moderator would tell me if something was out of line.
For what it's worth if you are the Will Prowse from Youtube I do appreciate the videos you make. Your channel has exposed me to companies I didn't know existed. The Hysolis tear-down was interesting and saves me from having to take things apart and risk warranty arguments with the vendor. There are some shady vendors making bold claims and it is nice to see which ones are the real deal.
I spent an hour yesterday deleting spam, and then I get emails from long time viewers stating that their comments have been removed. I cannot tell you how frustrating it is. I try to fix this every single day, and I get my long time viewers to report the spam. Youtubes system is awful.
Thank you!! Hysolis is awesome, and with the LF inverter, you can easily work on it yourself. I am glad my videos help :) There are tons of scams online these days, and I love exposing them.
There are tons of scams online these days, and I love exposing them.
Please keep up the great work. That is a very worthy battle and will save people a lot of frustration and money.
I plan to get 3 of the Hysolis portable units. Last I checked they didn't have the external battery available as an option yet so I've been holding out. I'm also hoping they have custom shipping options because Amazon uses UPS and they track snow into their trucks which isn't great for electronics. That inverter is heavy so it will be on the floor of the truck for sure.
That's hopeful, with that kind of following he has some serious responsibility. At the same time, I cringe when I see people working with large packs on workbenches with loose metal laying around, totally irresponsible pack geometries where balance wires cross and recross each other with abandon, recycled cells that have visible external damage and so on. Youtube is a great way to pick up some 'worst practices' thinking that if these youtube stars are doing it it must be ok.
Like what?! Can't any of you people backup your claims. It's just empty complaining on this site without evidence. It's driving me nuts. Show me what I said or have done that was wrong.
Mate, I've been following you for a while and have a generally positive opinion of you. I think you're not going to have a good experience coming here with your guns out. I watch all your videos, but wouldn't I be a fool if I just absorbed what you say as gospel? You don't do this yourself, don't you?
I'm happy for you and your success and I'm very happy there are people out there like you changing their life outcome out of sheer will, while providing the community with unbiased product reviews and independent tests.
Please don't take the criticism as a personal attack. Unfortunately, I just don't recall which information you said at some point that made me cringe. Like I said, I've watched a lot of your videos and haven't had any cringe moments like this for a while now.
EDIT: also fyi, this website has an automated banning process if you're a new account with too many downvotes. Unfortunately, the few messages you've written have a confrontational tone that usually attracts a lot of downvotes. If you care at all, may I suggest that you avoid that tone/style. I'd love if you posted here in the future. Take that as you will.
No of course not, I just see people on this site stating to use recycled NMC cells that are capable of burning down their house with one wrong move, then saying my videos are dangerous. I cover safety all the time, more so than any other channel I know. I do not understand why people are saying these things. I work very hard to make my videos, and people here on this site who do not understand batteries are trying to criticize me. It really makes me mad.
And thank you. Just figured out the automated banning process and am using a VPN now. I just want to respond to people, and I hope they can provide evidence of when I did something dangerous. Or said something wrong. And yes, I see what you mean about the downvotes. I am very upset right now because I could argue every point made against me here. I also allow people to criticize whatever they wish on my forum, so it makes it hard on this site where I am instantly censored if I get downvotes. It is very frustrating.
Just a tip that while HN looks like reddit, it's not reddit. And deliberately so.
E.g. you can't downvotes responses to your own comment. This to steer into a different type of conversation.
I can't say I've fully internalized it, but it does make for much less shitposting compared to reddit.
The downvotes i don't think are due to disagreement or even anger.
I understand your frustration (especially since the critique is so unspecific), but i believe the downvotes don't mean what you think they mean, and it's not personal.
Is going to bolster your reputation as safety conscious or harm it, besides your general attitude in this thread. You are quite clearly advising people to copy this design, you make money of them doing so. Even a one-off should be better designed, let alone something intended for duplication.
I had you down as well meaning but a bit out of your depth at times, let's just say that that didn't improve based on the interaction here and your various comments.
That's a functional system that is 100% safe. There is no battery inside either, and I am using surface mount components that are recommended to be used on wood. It's a great little box. What's your problem with it?
The comment despite having some useful sentences, is too confrontational for this site and someone flagged it. I would love to see substantial comments from you here. Check the guidelines linked at the bottom of the page.
My opinion of him after his attempts to interact in this thread (turn "show dead" on - a bunch of his more arrogant/abrasive posts have been killed, and it looks like he's posting as Solar2 as well) is now far, far lower than it was.
Why?? I must admit, I don't use this website, but a close friend does. I am blown away by the ignorance in understanding lithium ion batteries here, and seeing people here try to crtiicize everything I do pisses me off. How would you feel? I cover safety more than any other channel and constantly work to bring the best diy solar videos online, and this is how people respond? I love criticizism, but this is just silly. People here are fighting for lead acid and saying they are superior? And I don't think they are joking either. Also getting a lot of people mentioning to use recycled cobalt based chemistries that can set your house on fire? This site is dangerous. On my forum we have actual electrical engineers who will destroy you with evidence and list relevant literature. On this site, it is emotions based and no one knows what they are talking about. It's wild. I am mad.
Ditto. I had him pegged as well meaning but sometimes a bit less knowledgeable than he wanted to come across but that didn't stand the test of interaction.
Where would you get the idea that I am not "well meaning"?!? The majority of my videos are exposing scams and rips offs. I constantly bash companies that do a bad job and back up everything I say with evidence. There are extremely ignorant comments here from people who have no clue what they are talking about. I work with batteries every single day and talk to head engineers that are leading the space, and everything I say can be backed up with recent battery studies. There are numerous comments here suggesting to use cobalt based chemistries that can burn your house down and everyone is fine with that? It's ridiculous. I am mad, and this type of ignorance is why I make my videos. I love criticism, but the comments in this thread are plain ridiculous. I am not familiar with this site and that is my fault, but geez, saying I'm not well meaning?? Why?
The website's author hosts an excellent forum [0] focused on DIY solar power, for anybody who wants to get a bit deeper in to this and has questions or needs help sourcing parts (like LiFePO4 cells and BMSes) from China.
I recently built a LiFePO4 battery and upgraded our caravan (trailer) electrical system following these guides and with help from the forum. Couldn't have done it without those resources.
And there is zero corporate interest and I pay for it out of pocket. It is free for everyone! We have head engineers of solar equipment companies interacting with people in third world countries. it's really great!
For folks interested in a more basic, low level, open source approach to this topic, check out Electrodacus [1]. I built a small system using the SBMS0 in my camper van and have been pretty pleased with the results. If having access to schematics and source code is important to you, have a look.
This is a spanish guy who built his own off-grid setup with solar panels and 18650 batteries. As a complete ignorant in electric stuff to me this is amazing. If you know some spanish you can find here a good channel IMO!
Those cells are very dangerous to use. stick to LiFePO4 or LTO. Cobalt based chemistries can experience and awful thermal runaway when over charged. This can occur if you have a shorted fet in your BMS. Which can happen from inrush current or high voltage.
NGL I think I have a pretty efficient setup and I'm in the process of installing a 4th panel (bringing my total to 1220W) because 915W isn't really cutting it for winter power now that I'm not spending time outside much. My quiescent draw/day is about 500Wh just doing nothing (fridge + internet) and on a cloudy day I'll make maybe 800Wh with the current setup. I don't think 800W of panels will let you power anything you want during winter.
I'm also working on a way to bring power in from my alternator but unfortunately I think I'm going to have to invert in the engine bay and rectify feeding into my MPPT controller to avoid running some absurdly thicc wire to carry a few hundred watts at 12 volts.
When I looked into this previously I wasn't able to find a suitably sized boost converter but it seems like there are higher capacity ones cheaply available now. Thanks for the suggestion I may very well end up doing this.
As I wrote a few weeks ago, I have been successfully running an on-grid 5Kw solar system that has immensely helped me.
The on grid part helps with credit banking during summer and using in winters. For that, I changed my on grid inverter with a "phocos solar inverter" that does the same thing but also, when there is a grid power outage, it still supplies power to home without having batteries.
I haven't bought batteries because of the cost but this has been a good experience.
My panels are 16*325W and I produce around 30Kwh during the day in summers and during the current winter, I get enough to run appliances, rice cooker and lighting.
Together with my girlfriend I’m planning a trip.
Driving from the Netherlands to South Africa and back with an EV.
We want to charge the car with solar panels we bring with us.
See our website for more details: www.4x4electric.com
Challenge for now: how to charge the car with ~60m2 of flexible solar panels.
We need a threephase offgrid solar system, but did not find a suitable solution yet.
Perhaps it makes sense to have a chat with Solar Team Eindhoven/Twente/Delft?
Or have a chat with the people at Lightyear. They have a lot of former teammembers.
Good idea! We are already in contact with Lightyear. They like our idea, but are to busy at the moment to be part of our project. We wil contact the solar teams!
I am building an off grid / backup solar install for a house in rural Romania. I want it to be off grid capable, but also be able to use the grid when available.
One thing I am curious about: do the all in one systems like Growatt or MPT also provide voltage stabilization? The grid here has really bad voltage stability.
Sometimes the voltage drops down to 180V (should be 220V in Europe). Some devices like LED lightbulbs and washing machines don't like this at all.
So if these devices provide voltage stabilization, that would be great. I would then buy one and a few batteries, and later add the PV panels. It is going to be about 12kW of roof integrated PV.
Offgrid inverters either get the power from the batteries/charge controllers or they get the power from the grid (usually to charge the batteries - they are called charger-inverters, look at the Outback VFX series for an example). This means that either you get the unstable grid power or you get the stable solar/battery power. Maybe there are inverters that somehow compensate and correct the power but I doubt it since they would be fighting the rest of the grid.
I would suggest that you add solar with a small battery bank and use the grid for overnight and for dark day charging. This way you have the best of both worlds as you only need a big battery bank if you need a lot of power when there is no sun.
P.S. Start with a 48 system since you are going for so much solar power. It is safer and cheaper in the long run.
Maybe the all in one system is not good in that case. I was hoping that since they already have the AC-DC inverter built in they could also do voltage stabilization.
Maybe charge the batteries from either the grid or the PV panels, and always run the house off the batteries via a separate inverter. That way, you got the inefficiency of AC->DC->AC but always have stable voltage.
In the long run I want this to be mostly off grid anyway, with the grid as just an emergency option...
Yes, that is a good idea. Get a separate charger and always run the house from the isolated side. This will be more expensive as a good inverter/charger runs in the 1k-2k Euros area and you would need two (unless you find a suitable battery charger which is not very easy). I lived offgrid for nearly a decade and built myself three different solar systems. I started with a small all in one and found out that they are limiting when you want to expand since you usually cannot add more charge controllers and/or panels (which are the easiest way to expand a system). I ended up giving it away and building the others from separate systems. My biggest mistake was starting with 24 volts instead of 48 volts. It is cheaper but it gets a bit dangerous as you step up the power usage and there aren't many options for breakers and such.
I can't speak to all equipment but Victron inverters can handle this situation. If the voltage is outside the desired range it will augment with batteries or switch over to batteries entirely.
What you want to look for in an inverter is called brownout protection capability. This is usually the higher end of the inverter ranges but quality gear can sometimes be bought second hand from marine salvage companies.
Just a (hopefully amusing) piece of anecdata: we have a squaredrop trailer, with a set of solar panels to power/charge the 12v marine battery and a pair of Jackery power banks. Most of our camping is done in the eastern woodlands: WV, PA, VA, etc.
There is so much tree cover all the time. Some days, even though it's mostly or fully sunny, we're almost always at the end of some disused fire road on the wrong side of a mountain, and we're lucky to get a couple of % back from all-day charges. I'm considering one of those water-powered turbines, since it'll work all night long as well.
Do eastern fire roads often feature fast moving creeks? I kid.
Are you able to tilt your solar panels? If they are lying flat on your roof, you won't get much power from them.
Speaking as someone that has spent the last three summers off-grid in a forest, in your situation, I'd add the ability to tilt the solar panels, reduce power consumption, and get a multi-fuel (propane and gas) inverter generator along with a propane tank. The inverter generator is a lot quieter, smaller, and lighter than generators. I don't need much power and mostly use the generator for the microwave and occasional topping off the batteries.
I live in an off-grid house. Solar isn't perfect, but it's been pretty good all things considered 6 months in. Converting an airport shuttle bus into an RV now, so I'll have to look this over for that.
This is super awesome! I do some overlanding/longer roadtrips in backcountry but have yet to gather the courage to install a solar system. Certainly bookmarking this for future reference :D
If you're going to do solar on an RV, you really should read Handy Bob Solar too [0]. The site formatting sucks, it's very much wall-o-text, and he's absolutely right in everything he says and rants about regarding RV solar.
Far too many solar installers just treat a system as the entry to people coming back for more, when the problem is that they don't know enough to adjust it properly for the stuff that was installed in the first place.
//EDIT: So, apparently, a site that's been static since 2011 and I've linked quite a lot over the years was updated again in 2020 with some ranting about Covid. You can safely ignore that, and read his older writings on solar installs, because just about everything he says about that is correct, at a "Spend five years hands on with solar and you'll eventually come to agree with him, no matter how loony he sounds about some of it when you start in."
Nice, someone with a non standard/officially approved opinion is a loony and is served with such epithets as "f*ck is with the antivax covid-hoax propaganda".
Read the rest about solar, I actually just grabbed it from my bookmarks and didn't realize he'd posted anything new since 2011. Ignore the first few posts and carry on reading his rants about solar, batteries, wire gauge, charge controller location, charging voltage, panel placement, shading, etc.
I've been dealing with an off grid solar office for 5+ years now. Year round power, heating (propane at times, candles/kerosene at others, electricity most of the time if I have the light), and have spent the bulk of this time in some esoteric backwaters communities on IRC with other people who do the same sort of thing.
It's really, really hard to find people who have written accurately about solar on the internet. What he said about solar, RV installs, battery charging, etc, is all 100% accurate. He deals with the broken installs by the places that advertise that they know what they're doing.
If you're willing to toss all that out based on more recent writings, it's your choice, but I try to judge writings based on their accuracy, not what I think about the person. You're entitled to judge writings however you want, but if you're considering off grid solar and write the guy's writings off, your loss.
How intelligent can the guy be when he's flagrantly demonstrating such flawed thinking? It calls into question everything he writes, full stop. Better things to do with my time and why give him more audience.
Intelligence has almost nothing to do with it. The whole 'rona thing has been very very stressful and many people have not reacted well to it. Scam artists have exploited this stress (as they always have and always will). Some people have been led astray and some are leading people astray, and some are both.
At any rate, it is an impairment of gathering and processing information correctly, not intelligence. It's a filter problem. I had a really hard time with this too, after seeing how people I previously respected dealt with this whole thing.
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For what it's worth - I'm strongly in favor of people choosing to get vaccinated and masking up in public. I despise the people who made this a wedge issue for their own benefit.
I also think that being self-righteous about it is very tempting but also very bad and destructive to discourse.
People who disregard everything someone has to say based on one belief are generally pretty stupid themselves. What an impressive way to discourage critical thinking.
I should judge the accuracy of what someone wrote nearly a decade ago by what I think of what I think they believe today?
It's a popular enough viewpoint today, certainly, but it leads to throwing out huge swaths of perfectly good work that could be useful. Obviously, I reject it. I don't know the guy, I don't know what's happened to him or not in the past decade since he was writing on the deep truths of RV solar. I do know that the more I learn about solar from hands on operation, the more his writings reflected what I'd found through experimentation/analysis/etc. You could apply plenty of his rantings to some of the off-grid battery destroying systems presented on YouTube as Grade A Amazing builds and improve a lot on those systems.
But, if you're only willing to consider the viewpoints of those you would consider show clear thinking, which largely translates to "agrees with what I already think," you're welcome to go through life that way. I tend to find that dreadfully boring and a good way to miss an awful lot of really solid knowledge. I'm happy to learn about lead acid battery quirks from people who've lived with lead acid for half as long as I've been alive, even if I think they make some pretty dumb decisions in life. I know they question some of my decisions back.
Anyway, your mind is clearly settled and the issue is closed on this particular bit of writings. You might go find some of SunKing's rants about "max smoke charging" useful as well, if you're dealing with off grid lead, but I guarantee you won't like him much as a person either.
There are many intelligent people who purport to be Christian/Muslim/etc, which all require severely flawed thinking to seriously believe.
What you’re doing is conducting an ad hominem attack, assuming that this dude’s views on one topic have any relevance to the accuracy of a completely different topic (with a nearly decade gap nonetheless).
Do you ensure that every bit of material that you read isn't written by someone who also has some really stupid and harmful beliefs about some other topic?
> Do you ensure that every bit of material that you read isn't written by someone who also has some really stupid and harmful beliefs about some other topic?
Everyone makes mistakes, and I've been known to rescind my references and recommendations upon making such discoveries.
In this case all it takes is simply loading the referenced page, the hogwash is front and center. Give me a break.
> ... and I've been known to rescind my references and recommendations upon making such discoveries.
Why?
If person A makes some claim about subject X at some point in time, and you find it true and worth sharing, what then makes their claims invalid if you discover later that person A believes something you find distasteful? If their statement about X was true at the point in time it was made, is it any less true if you discover you can't stand the person?
What if you read a book by someone who makes well written arguments and an enjoyable read, and then attend a book signing years later and realize that they have rancid BO or something, and are oddly vocal about [insert some fetish you find exceedingly disgusting here]? Does the character of the author you discover later impact the arguments in the previous book?
It's a really odd and, IMO, exceedingly broken filter for what sources of information you're willing to consider. It makes it really easy to never go outside your own head, because anyone who believes all the same things you do can't have anything terribly interesting to teach you, and anyone who believes different things can be spun as somehow abominable.
I'm not nearly so arrogant as to think I know everything. I'm certain there are things I'm wrong about, though I've no idea what they are at the moment. I'm equally certain that I have rather different opinions about subjects than many of the people I interact with, either in person or online. Some of them make for interesting conversations (I prefer a fire pit, pipe or cigars, and a bit of whiskey to make things civil), some of them we simply agree not to discuss, and that's fine.
> I've been known to rescind my references and recommendations upon making such discoveries
You understand that most everybody who was born in the first part of the 20th century or earlier believed quite a few things that we now consider pretty abhorrent.
I've driven something like 60,000 off-road miles since I bought my first truck in 2005. For overlanding, all you really need is a one big, high quality battery. The Odyssey PC2150 series are great batteries. Not cheap, but fantastic. It's very difficult to kill one.
Also, you'd be surprised how little energy you actually use out there. A quality fridge-freezer like an Engel or ARB can be run for days before it will discharge the battery in a parked truck enough to not turn the starter. This scenario pretty much never happens, so get a good battery, a good fridge, and you'll be fine.
Out of curiosity how far off grid do you go in your truck. That is, how far by distance and time are you away from the grid and stores? I know little about this stuff but am interested and would appreciate any helpful resources or videos you know of for a newbie. I’m interested from an overlanding / camping perspective but also a bug out vehicle perspective.
There's only so far you can get off-grid in the USA. The most remote is probably the Owyhee Desert, which is centered around the intersection of Oregon, Nevada, and Idaho. Out there, you can easily go 80-100 miles off pavement, sometimes further.
Another similarly remote place is the Arizona Strip, the portion of the state that lies north of the Grand Canyon. You access it from Utah and it's 95 miles from the outskirts of Hurricane, UT to SB Point, above the canyon.
Generally, we stay out for about a week and half and come in to town every 2-3 days, mostly for gas. We run Engel fridge/freezers, which give you essentially unlimited cold drinks and the only real limitation is space for fresh food.
It is an interesting feeling when you are truly bugging out or off the grid, almost a primal kind of thing, because instances where self reliance is the only thing left is becoming less and less of an occurrence. If you ever go camping in the wilderness by yourself and set in for the night alone, you probably know the feeling!
I want to add some panels at my home to lower the monthly power bill but as I understand I have to direct the energy to something, such as fridge or AC, and when there is not enought energy from the sun either automatically switch to grid or manually.
Where can I find such information to build a hybrid energy solution?
All grid-tied solar panels (i.e. what you get when you install solar panels at your home) will do that automatically. Don't don't have to do anything.
Solar will be consumed in priority. If there's too much it will be sold and if there's some missing il will be automatically (by the laws of physics) imported from the grid.
I used the Solar Controller+Inverter Combos recommended on this site (Growatt) but ultimately switched to ones by Renogy. The Growatt one I purchased has a wifi adapter and app - wifi requirement was a deal breaker when remote. The renogy one has a Bluetooth adapter and app, plus feels better designed (though actually I think the internals are all pretty similar).
There are a couple surprise gotchas I didn’t know:
1) These Controller+Inverter combo units require a battery to turn on. This means: if your battery runs completely out of charge, you have to get electricity from somewhere to charge your battery a bit before the Controller+Inverter will turn on and charge your battery again. I was pretty annoyed at how not “off grid” this felt.
2) Temperatures below freezing are bad for batteries. I purchased a Renogy 48v smart battery with self heating. Unfortunately less sun in winter means less energy, and heat production is energy intensive. I’m not at the cabin 100% of the time so I have to take the battery with me when I leave to avoid spoiling/freezing it. Still not sure how I’ll ultimately get around this.