Working Air Battery

[jeanna]

I really do like the idea of a wet cell using metals just laying around and discarded. I'll try to work on something along these lines also, but that would have to be another topic.

yeah, me too.

The magnesium is one of those fire starter plates. I bought a few off ebay a while back I can't remember how much I payed I don't think it was too much though.

Oh OK. It looked like a shiny piece of metal like a wide ribbon.

Just a side note on the aluminum can thing, it's funny I didn't scrape anything off it and it still worked. Now you got me thinking about how much power I could get if I had scraped the inside. 

Some cans do not have plastic.
Coke does.
Maybe 7up doesn't?
I don't drink soda any more so I don't remember which ones are OK.

update on the plate cell I did last night, it's been running for about 10 hours now, no additional water although it's only running at about half brightness now, we'll see how it holds up throughout the rest of the day. Thanks again to everyone.

Excellent.
mine keeps loosening.
I have to figure out how to make it stay tight.
And, the thing about the can... It is really loose, so it won't be as good.

I love these lasersaber air/not air batteries!

jeanna

[Pirate88179]

Jeanna:

You are familiar with the terrarium principle right?  Possibly the thing to do here is to place the battery into a air-tight zip-lock bag (one gallon freezer style with the mechanical zipper built in) so when the moisture evaporates, it is enclosed into a sealed system and may never need watering again.

Just a rambling thought.

Bill

[jeanna]

Hi Bill,
Yes, that would work... good idea!

The high humidity inside the closed bag could make it like Lasersaber's  environment.

I am still struggling to get more than 20 mA from the  1" copper pipe.
Maybe it is necessary to have carbon, as lasersaber says
I hope the copper can do this because it is so much more affordable...$3.50 instead of $45.00.

The very tiny one like "pete'sAA" (C-Mg) shows me by the flicker when it is getting dry.
I spray it and the flickering stops for 5 or 10  more hours.
It has been on steadily since I made it a couple of days ago.

The 5 1/2 " carbon rod that I made last week and covered with masking tape only works for 2 hours on a wetting.
I am ready to soak it for a while to see if I can revive it at all.
I think some epsom salt might be the thing to get this going.??
I will let you know.

The trick for me seems to be to get enough air and moisture to let it run, but to not destroy it.

jeanna

[PeteIdl4]

Good work Jeanna, I also agree the trick is to find a way to get the right mixture of air and moisture so it'll keep running and not destroy the mag so fast. We have been making progress though all the new air batteries I've built seem to be outlasting the previous designs the mag ribbon still looks like new.

@Jeanna,
The plate cell I made uses only copper and mag, no carbon. It gets a very good amount of power for being so small. It was able to light a white led at full brightness more than 24 hours later off one ML of water.

I Just added a capful of water to it this morning to see what's the most mA I can get out of it. The amperage rose steadily for about a minute and finally peaked at about 99mA, but if I hold the center tight it rises to 120mA. So I put a clothes pin on the center and it held steady at about 109mA. I will be redesigning this cell as soon as some parts I ordered arrive, I was thinking of making a youtube account to show the disassembly of this one and the assembly of the new ones if anyone is interested to know.

-Pete

[jeanna]

Pete,
Do you have 2 connectors to the copper each coming from a different magnesium source?
Please explain how you are wiring that.

I am getting 100 uA now from the carbon rod and mag ribbon covered with tape. 
(the tiny one which is not covered is still on.)

@conrad,
I made a carbon/Alu battery from an aluminum soda can filled with carbon wrapped in paper towel.
the carbon is the granules of a spent carbon filter with a carbon rod in the middle for the electrode.

The volts are OK but the amps don't even show up on the meter. This means it is less than 1uA.
It is very disappointing, but there it is.

I guess I could add some sodium carbonate as I did with the foil experiment.
I will let you know if that works, but for now, this seems in need of a lot of improvement.

jeanna

edit... I added some sodium carbonate and the uA went up to 500uA. This is an improvement, but not enough.