H20 battery questions...

[pdw709]

I've seen a few people on TV/internet talking about the "H20 Battery" which they say can run low powered items such as clocks etc for a couple of months on nothing more than tap water.

http://uk.gizmodo.com/2005/11/14/waterpowered_clock_for_hippies.html

At first my bullsh*t radar went off the scale, however it does appear that the product does indeed work, but only for very low voltage/current applications, such as the clock mentioned. The problem is I'm finding it very hard to to find any scientific description on how the battery works. I've also seen people claim that they are working on a way of "scaling up" the process for much more power hungry applications.

The question is........will this work?

Phil

 

[TobiasTheViking]

I've seen it used for clocks and the like. Very cool.

 

[rtalman]

The question is........will this work?

Phil

Copper plate on one side, silver plate on the other, salt water for the electrolyte, you've got a battery. We made much the same thing many years ago when I was in high school using pennies and dimes.

 

[phildonnia]

I used to have one of those "potato clocks" that used a zinc and copper plate inserted into a potato. At some point, the potato decided to start growing, and I wondered if it would replace the electrolyte, given enough sunlight. Alas, I am no potato farmer, and the whole thing eventually died.

 

[Buckaroo]

I'd like to see if this battery would work with distilled water, where there aren't the impurities of tap water to act as charge carriers.

 

[Ziggurat]

What a joke. A perfect example of naive environmentalism backfiring.

The thing doesn't run on water. It's got something like two metal electrodes which use the water as an electrolyte for low-power operation. Nothing especially remarkable about that. Supposedly the battery is replaceable, but no indication of how much it costs. And while it says that the battery lasts a minimum of two years, my guess is you won't get much more than that out of it either. I'm also guessing that the battery is a big part of that 15 pound cost (which seems like a lot of money for a tiny clock). So what will probably happen is the customer will buy it, use it until the battery dies, have trouble finding a replacement battery or find out that it's more expensive than the damned thing is worth, and chuck the whole thing in the garbage and buy a new clock (likely a different kind). And which point they will have spent more money and created a bigger environmental impact than if they had just gotten a sensible clock with standard rechargeable batteries to begin with.

 

[Buckaroo]

What a joke. A perfect example of naive environmentalism backfiring.

I imagine most people who buy it aren't doing it to save the environment, but simply for the novelty of owning a "water-powered" clock.

 

[Ziggurat]

I imagine most people who buy it aren't doing it to save the environment, but simply for the novelty of owning a "water-powered" clock.

The Gizmodo site linked above seems to be mostly gadget-oriented, with novelty being a sufficient appeal. But the site it's actually being sold through is "nigel's eco store". Ecological appeal is pretty much the whole point of that store.

 

[Psi Baba]

So what will probably happen is the customer will buy it, use it until the battery dies, have trouble finding a replacement battery or find out that it's more expensive than the damned thing is worth, and chuck the whole thing in the garbage and buy a new clock (likely a different kind). And which point they will have spent more money and created a bigger environmental impact than if they had just gotten a sensible clock with standard rechargeable batteries to begin with.

Exactly. For that price you can easily get a clock or a watch with an included lithium battery that might last 5-10 years. I couldn't tell you the last time I bought a watch battery, because the battery usually outlasts the watch itself.