Working Air Battery

[PeteIdl4]

I did not drill the little hole in the carbon. I just wrapped  some A copper wire around it about 6 times. Maybe I should try the little hole on one.

I don't think having the hole or not really makes a difference. I use the same method as you on my bigger air batteries, I just wrap bare copper wire on the end. Although having the hole does make them easier to work with.

-Pete

[conradelektro]

@ Mk1 - moisture in cement or tile cement ?

My "copper - tile cement - aluminium cell" is now on for about 4 weeks (red LED on the Joule Thief circuit is glowing), so I can not tell any thing about 4 months. But I intend to keep it going as long as possible and will report the result.

Some observations (see the attached photo):

- the tile cement is only about 2 to 3 mm thick, therefore it has dried out much faster than a big volume of concrete; also the little holes in the aluminium sheet let moisture out

- but I think that moisture from the air goes into the tile cement, because the cell becomes weaker when the air is very dry and recovers when the air is damp (rainy day, in the morning when dew settles everywhere)

- I also submerged the cell in water one time and it recovered strongly (the LED became brighter), but damp air is much better and more practical

- when I put the cell in bright sunshine for some hours it becomes weaker, what I attribute to the evaporation of water from the cell (but first it becomes stronger for some time, because the water in the cell is agitated by the temperature increase)

- it is important that the layer of tile cement is as thin as practical (too thick, the effect will weaken; too thin, the cell breaks easily)

- I like the voltage (1.02 to 1.17 Volt depending on air humidity), but the amperage (about 0.15 mA) is a bit disappointing; I will try bigger cells and more cells in parallel


At the moment I am building a cell with mild steel - tile cement -aluminium, to see how this will do.

Other materials will work much better than tile cement. But tile cement is very practical because it strongly sticks to the metals, gives the cell a nice rigidity and sturdiness and can be bought everywhere. Good tile cement also withstands freezing.

Greetings, Conrad

[PeteIdl4]

Nice work Conrad, I like the design of your cell I'm sure there must be ways to improve on this. I was thinking about what you said about using aluminum for an air battery design and i made one tonight. So far the readings look good, not as much voltage and amperage as the magnesium design but that was expected, but hopefully this one might last longer. I built this one using a 4 inch carbon rod, I wrapped some aluminum i got from a soda can around it and taped it. I'm still using a paper towel with the same solution I mixed before for the layer between the two. So far I get .7v and the amperage holds steady at about 12mA. It's enough to light a white LED, but at about half brightness. I'm sure if I add a cap I can brighten the LED a bit more, possibly full brightness. I plan to build one using foil also, but I like the idea of using cans as there's so many thrown away everywhere, plus I think Jeanna has already tried foil. Hopefully she can enlighten us on her results and experiments a bit more, I know she mentioned that the reaction was creating H2 gas but i don't know what her set up was. Here's a picture of the cell, and once again nice work on your cement cell Conrad.

-Pete

[PeteIdl4]

Hi Everyone,

Just thought I'd share with everyone a new cell design i just built, this one really surprised me. It's composed of a magnesium plate wrapped in a paper towel, wound with copper wire then wrapped in another paper towel, and finally wound with magnesium ribbon. The dimensions of the cell are 3"x1.5" The readings are 1.3v@75mA. It's been lighting the three white LEDs off 1ML of water for about 2 hours now and doesn't show signs of dimming yet. Here is a picture of the amp reading and lighting the LEDs.

I will see how well this holds up overnight and through tomorrow hopefully it doesn't destroy the mag plate too fast.

-Pete

[maw2432]

Nice job Pete.  Is your copper wire bare wire or coated?

Also,  anyone every try using a chuck of coal instead of graphite?   

Bill