
Salt – Sustainable Alternative Lighting - lisper
http://www.salt.ph/
======
benjaminl
From the description this sounds like they are using a form of what is
commonly called a lemon or potato battery
([http://en.wikipedia.org/wiki/Lemon_battery](http://en.wikipedia.org/wiki/Lemon_battery)).
The salt water is the the electrolyte in the battery cell and the actual
energy comes from a chemical reaction between the zinc and copper electrodes.

In this blog post ([https://saltph.wordpress.com/2014/05/14/know-more-about-
salt...](https://saltph.wordpress.com/2014/05/14/know-more-about-salt/)) they
mention that part of their revenue model is "Electrode rod refill", and in
their main page ([http://www.salt.ph/](http://www.salt.ph/)), under "Our
Product" / "Just add water and salt!" they mention replacing the anode every 6
months. The anode they are referring to would be the zinc electrode. This is
usually a galvanized nail in those popular lemon / potato battery science
experiments.

------
dredmorbius
Absent cost and energy storage / delivery data, this is 1) noninformative and
2) bordering on gullibility marketing.

Yes, galvanic cells work. No, they're not magic. No, the salt water doesn't
"power" the solution (it enables electron flow between cathode and anode).

It's also not a rechargeable process, though it's possible to recycle the
cathode/anode, generally.

Solar power or other storage cell technology would be of similar use.

~~~
ArekDymalski
I think that by using the "powered by water and salt" phrase they are trying
to present the product in layman's terms. For most of the people it's
sufficent description to understand the product and using the "galvanic" term
wouldn't help to understand it better.

However it would be nice if they had a "how does it work?" subpage with
scientific explanation - for the credibility.

~~~
tjradcliffe
They are not presenting the product in layperson's terms. They are
misrepresenting it as badly as saying, "A car that runs on rubber! Just add
tires!" and then making money by selling buyers gasoline.

~~~
Elrac
Wonderful analogy! I liked it, anyway.

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Elrac
I resent the creators of this product for misrepresenting how it works. Are
they marketing to the gullible?

No, the water and salt do not power it - if that were the case you could
revive the lamp's battery by pouring in fresh salty water. Instead, the power
comes from the galvanic potential of a chunk of metal vs. (I'm guessing) a
carbon electrode. When the metal electrode wears out, that's what you need to
replace.

~~~
wnkrshm
I think the product may not be without merit (edit: entirely), even though the
marketing reminds me of free-energy pseudoscience. Within a region with many
islands, where technology is expensive because it has to be transported by sea
(with weight and space limitations increasing the cost), it may be much more
cost effective if you have batteries without needing to ship an electrolyte.
You can just cram more replacement anodes in a cargo hold than fully-fledged
throw-away batteries.

On the other hand - solar panels might be a better investment.

~~~
pge
I agree, and I think the focus here on the battery is misplaced. What is
enabling this to work is the availability of low cost LEDs, which require very
little current to operate. These open the door of all kinds of lighting with
low power sources, like galvanic batteries, or as you suggest solar panels
(though I am guessing the cost for solar is higher). Whether this is the
optimal power source is TBD, but the core idea that lighting can be brought to
developing countries at very low cost by looking at non-traditional power
sources is an important one.

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tenpoundhammer
Based on the video posted below by coob (
[https://www.youtube.com/watch?v=5vOuj_feM2s](https://www.youtube.com/watch?v=5vOuj_feM2s))
it looks like it utilizes a well known re-active element ( Zinc-Oxide) to
generate electricity.

[http://sci-toys.com/scitoys/scitoys/echem/batteries/batterie...](http://sci-
toys.com/scitoys/scitoys/echem/batteries/batteries.html)

So the real question is, how long does it take for the Zinc Oxide to be
depleted, how much does it cost to replace, and how hard is it to replace?

~~~
callahad
From the landing page: "Using SALt lamp 8 hours a day every day will give you
an anode lifespan of 6 months."

~~~
sbierwagen
Okay, with a pair of big electrode plates, retail cost will be, what, $200?

~~~
mbrubeck
You can get a 12" square sheet of zinc for under US$10 and make a couple dozen
anodes from it.

Copper cathodes will be a bit more expensive, but the total electrode cost
should still be only a few dollars for several months worth of light.

~~~
Elrac
Or the cathode is carbon. Then (IIRC) it wouldn't wear out or need replacing.

~~~
sbierwagen
[http://en.wikipedia.org/wiki/Galvanic_cell](http://en.wikipedia.org/wiki/Galvanic_cell)

The has energy come from somewhere. In an electrochemical battery, it comes
from chemical reactions with the electrodes, which consume the electrode
material.

~~~
Elrac
As VLM explains a bit better, I was talking about only one of the two
electrodes. The other one, the anode, would of course be made from zinc (or
some other metal) and end up breaking down to provide that energy. I was just
explaining why the battery might not need _two_ electrodes breaking down.

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jellicle
So this is a battery-powered lamp, where the saltwater is merely the
electrical conduit and the battery consists of the cathode and anode, perhaps
carbon and zinc. We already make batteries of this type, without the
gimmickry:

[http://en.wikipedia.org/wiki/Zinc%E2%80%93carbon_battery](http://en.wikipedia.org/wiki/Zinc%E2%80%93carbon_battery)

This same lamp could simply have a wire between the carbon and zinc, with an
on-off switch - no need for saltwater except to fool people into thinking the
salt is providing the energy.

It's very hard - impossible - to imagine how this device is superior in
performance or cost-effectiveness over any sort of commercial light with a
battery. An LED or three connected to a lantern battery, auto battery or other
"large" battery will last _forever_ , with self-discharge being the biggest
problem.

LEDs with solar cells are nearly free, and last forever. Here's one for $1.98
retail, Canadian:

[http://www.lowes.ca/solar-landscape-lights/paradise-
stainles...](http://www.lowes.ca/solar-landscape-lights/paradise-stainless-
steel-solar-powered-led-path-light_g1463441.html?ProductSlot=1)

In the not-distant past, many people were concerned about electric lighting in
the developing world. Cheap solar cells and cheap LEDs have solved that
problem, permanently. In the near future, I'd expect to see the average third-
world village a million miles from nowhere be lit up like New York City after
dark.

~~~
peterwwillis
Superior performance, No, it probably performs worse. But cost-effectiveness?

 _Salt water is free._

Why is everyone missing the point here? This is not for a geek in San
Francisco, this is for someone in a remote village on an island in the
Philippines that doesn't have a damn corner store to go pick up batteries at,
but does have _plenty of salt and water_. The materials will simply survive
better in this environment than traditional batteries, and need to be
replenished less.

Why is this so hard to grok?

~~~
jellicle
Wow, you missed the point hard. I guess I just assumed that people knew about
galvanic cells... Okay, I'm sorry, let me backtrack.

The salt water has absolutely nothing at all to do with the operation of the
lamp and it is not providing the electricity to operate the lamp. Salt and
water are not used up or expended in the operation of the lamp. It's like the
"lava" in a lava lamp. The lava isn't providing the power. It's decorative.

What is providing the power are two materials of different
electronegativities, which we call a cathode and an anode. They are expended
in the operation of the lamp. They are not free, are not available on remote
islands, and are to be purchased - like any other batteries - from the
supplier of the lamp.

Your response is exactly what the makers of this lamp are hoping for - people
who don't know the science ending up believing that salt water powers this
lamp, somehow. You have been deceived by their marketing.

EDIT: I responded to your one comment above without reading the rest of your
comments in this thread. Had I done so, I would have been much less nice, as
it is clear you are highly, highly ignorant and highly resistant to numerous
people's attempts to educate you.

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upofadown
I would be a lot happier with this if they had some actual numbers. As in, how
much light does the lamp produce and how much does it cost to replace the
electrodes after the 6 months?

~~~
impostervt
Or even just a price listed. I'd consider buying one for my home to fulfill my
once-in-awhile prepper thoughts.

~~~
lxmorj
Heh, I think everyone with a good imagination has at least lazily considered
being a prepper...

------
jimrandomh
As others have pointed out, this is a battery-powered lamp which needs salt
water as its electrolyte, but gets its power from a separate consumable.
There's nothing wrong with that per se, but the way they work so hard to
distract attention away from the battery is pretty scummy. Flagged, and I
encourage others to do the same.

~~~
lisper
They state in the first paragraph of explanatory text, "Replace consumable
every 6 months!" No, they don't emphasize this, but they don't hide it either.
I think flagging this is a bit harsh.

~~~
jerf
I'm going with flagging it, because the salt water is an irrelevant,
uninteresting side show. Compared to the cost of the anode and cathode
material in the first place, the salt water is free, so the question is "why
are they even making you put it in?" to which I can only answer "deception".
No, seriously, I took a moment to try to come up with an explanation that
didn't involve that, but given the physics here I can't. Pitching this as
either "sustainable" or "cheap for the developing world" is a lie, or some
sort of collective ignorance (where no one person involved quite understands
what is going on) that amounts to much the same thing.

~~~
VLM
wikipedia is a little wishy washy about "may leak". Much more realistic to
write "will leak".

[http://en.wikipedia.org/wiki/Zinc%E2%80%93carbon_battery#Lea...](http://en.wikipedia.org/wiki/Zinc%E2%80%93carbon_battery#Leakage)

Kept dry, it should store infinitely?

The greenwashing and poverty-washing or whatever is pretty awful. But an
eternally storable battery is kinda interesting.

------
shalmanese
This is extremely dumb. We already have units powered by a Zinc-Oxide
reactions in a conductive medium. They're called "bad batteries". They got
replaced by things called "better batteries". Any distribution challenge of
shipping new anodes every 6 months is going to be equal or greater than the
challenge of shipping a 24pk of new batteries.

It's neither sustainable nor cost effective.

~~~
peterwwillis
You use _ocean water_ to create _electricity_ , and you only have to pick up a
new anode once every 6 months. How is this not sustainable or cost effective?!

~~~
shalmanese
You have to pick up a new anode every 6 months only if you're powering a tiny,
incredibly energy efficient LED. You could power the same LED for 6 months
using 6 Li-Ion D Cells.

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yellowapple
I'm sorry, but as cool as this sounds, I closed the tab as soon as I read the
words "it's a SOCIAL MOVEMENT".

Why does everything have to be a goddamn social movement nowadays? It's a lamp
powered by salt and water (and - presumably, if I'm understanding this from
years of playing with lemon and/or potato batteries - some cathode and anode,
since salt water by itself isn't what's creating the electrical charge).
That's already awesome enough. Did you really _need_ to muddy that up with all
this "sustainable" "eco-friendly" bullshit?

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kozak
So, the anode is effectively the battery. It lasts for some time, then you
have to get a new one. So the question is in the price and availability of the
anodes.

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Raphmedia
Can I pee in it? (Serious)

~~~
JTon
Uh. Why do you want to pee in a salt water powered lamp?

~~~
Elrac
Because every human being is a walking, convenient source of an electrolytic
solution. This is something you can do if you're too, too lazy to mix and pour
water and salt.

The downside is that you'll probably end up with a smelly lamp, and some of
the other crud in your urine may muck up your electrodes.

I wouldn't recommend trying it, but the question, asked in the hypothetical,
was valid and justified.

------
ChuckMcM
Wow, this definitely seems to play into the hands of the gullible. Given two
pieces of information (salt water + replacable anodes) we can deduce they are
building zinc-air batteries. The same kind of battery is described on the Sci-
toys[1] site.

Basically this is a great way to sell Zinc. Not exactly "renewable" since it
takes more energy to turn zinc-oxide back into zinc than it produces when zinc
reacts with air.

On the plus side, carrying round zinc and copper (for the cathodes) without
the electrolyte is easier than full up batteries. And you may be able to get
water and salt on site. As a bonus you should get ZnO precipitating out of the
solution as the anode corrodes.

[1] [http://sci-
toys.com/scitoys/scitoys/echem/batteries/batterie...](http://sci-
toys.com/scitoys/scitoys/echem/batteries/batteries.html)

------
peterwwillis
Here's a bunch of smart, socially conscious people in the Philippines trying
to create a cheap, mass-market, sustainable product for the many inhabitants
of remote villages that have no reliable source of light or electricity, and
all the commenters of HN can say is "they didn't explain properly how the
power is generated! scammers!!!"

Talking about not seeing the forest for the trees.

~~~
ta75757
The complaint isn't that they "didn't explain properly". The complaint is that
they sensationalized an inaccurate explanation, without addressing the
fundamental technological question: _is this better than existing battery
technology and if so how?_ Does it last longer than current batteries? Didn't
say. Is it cheaper? Didn't say. Is it less toxic? OK, they said that it is
non-toxic, I still don't know if it's _less_ toxic than existing alternatives.
If you want to convince people that you have a superior technology, well then
you have to actually explain your technology, not just say OMG Electricity
from Salt Water!

------
joshuaheard
This would be a great idea for emergencies where one loses power for an
extended time. I researched emergency equipment and ended up buying several
hand crank flashlights.

Solar lamps tend to be too bulky and cumbersome. This would be a good
application for a whole room solution. I think there is a bigger market for
these than they think.

~~~
greglindahl
Search for [solar reading light] on Amazon; I see lots of inexpensive, not-
bulky-or-cumbersome products for sale.

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wspeirs
OK... so how does this work? Fuel cell?

~~~
coob
[https://www.youtube.com/watch?v=5vOuj_feM2s](https://www.youtube.com/watch?v=5vOuj_feM2s)

~~~
dredmorbius
Title wouldn't hurt for your bare-naked URL: "How to make a Salt Water Battery
Lamp."

(I was expecting a spoof meme along the lines of "Magic" and very nearly
downvoted your comment simply based on that expectation.)

------
lisper
For the record, one of the mods changed the headline from what I originally
submitted. My original headline was "Water + salt = 8 hours of light". The
actual title of the page is "SALt - It's a Social Movement."

------
ta75757
Electricity from water and salt? Why don't they just use cold fusion?

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aravan
Great.. Just watched this youtube video Energy from Salt water

[https://www.youtube.com/watch?v=VMdS65_E_X4](https://www.youtube.com/watch?v=VMdS65_E_X4)

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dcre
Nice site, very cool product. Small tip — the quotation marks are unnecessary
(and kind of amusing) in the following line:

> powered by "tap water" and "table salt!"

~~~
ConceptJunkie
This is true. It should say:

"Powered by" salt water and table salt

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spb
Before I read the page to find that this is an actual project from the
Phillipines, I thought the ".ph" was just a clever domain hack.

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plg
show me the schematics

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nashashmi
How is this possible?

~~~
dmd
It's not. It's a scam; the battery is the metal.

