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Author Topic: Working Air Battery  (Read 221299 times)

PeteIdl4

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Re: Working Air Battery
« Reply #60 on: June 19, 2010, 08:03:12 AM »

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

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Re: Working Air Battery
« Reply #61 on: June 19, 2010, 10:23:35 AM »
@ 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

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Re: Working Air Battery
« Reply #62 on: June 19, 2010, 11:11:34 AM »
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

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Re: Working Air Battery
« Reply #63 on: June 19, 2010, 12:36:39 PM »
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

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Re: Working Air Battery
« Reply #64 on: June 19, 2010, 02:19:04 PM »
Nice job Pete.  Is your copper wire bare wire or coated?

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

Bill

conradelektro

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Re: Working Air Battery
« Reply #65 on: June 19, 2010, 05:03:01 PM »
@ Pete (Idl4)  -- I am very impressed by the Amperage of your cells!

One could put your magic mixture 
Quote
(4 cups of water 1 tbl spoon of salt and about another tbl spoon of baking soda.)
  in a plastic container and submerge two different metals in it (e.g. aluminium cans and lots of copper wire from old cables). If one seals the container fairly well this should last many days if not months.

Wet paper is o.k., but may be one should go all the way to very simple "wet cells" for a stationary home built battery (simple as the liquid is concerned, no acids, no fancy chemicals; just water, salt and soda). The optimal amount of salt and soda should be found in order to avoid waste.

The shape of the metals is then not critical, as long as they are covered by the liquid and do not touch. This should reduce the work needed to prepare the metals. Pieces of plastic could keep the metals appart.

This is of course classic text book stuff, but why not, as long as it is simple and cheap. The "progress" is the recycling of metals and the simplicity of the set up. It does not hurt that the chemical reactions are known since a long time.

The idea is not an "industry" or "money making by new inventions", but some savings and primarily enjoyment by using home made batteries for low energy applications like radios, charging hand held phones and music players or for vintage lights.

It is efficient to re-use thrown away materials. And the Joule Thief type circuits solve the "voltage transformation".

Ideas are floating around in my head.

Greetings, Conrad

jeanna

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Re: Working Air Battery
« Reply #66 on: June 19, 2010, 08:05:46 PM »
@Pete,

Where did you get that magnesium plate?

I was referring to the crystal cells when I said they made H2 gas.
Stephan made a suggestion once which I tried and which worked very well.

It was Al foil and C graphite from a pencil. (I think charcoal doesn't work well??)
I needed to make 2 in series to light a led, but it worked for quite a long time, like 2-3 days. It is on localjoe's thread which started out as an earth battery thread.
I am sure it could have lit a led with a joule thief circuit, but that was before I knew how to do that.

I used sodium carbonate for the electrolyte in the water.
It is a little more active than bi-carbonate and really worked.
The Al foil got gunked blackened, and probably it would have continued to work if I had cleaned it.

@all,
I was searching for magnesium yesterday and came across information that magnesium is alloyed in the aluminum of soda cans to make them more flexible and easier to form. There is not much, but it should make the Al more active.
BUT
remember you must scrape the plastic from the interior of the cans or you will get nada.

So, maybe a carbon rod or a copper pipe wrapped with salted paper and then dropped into a scorched soda can.
Maybe some fiberglass insulation or old T-shirts could be used to fill the space in the can so it would not need to be filled with liquid, but just be damp.

Right!
WE can recycle our own cans... and make our own power at the same time!
(and we can seed the gulf waters with oil eating microbes too)

 :D,

jeanna

PeteIdl4

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Re: Working Air Battery
« Reply #67 on: June 19, 2010, 08:13:12 PM »
@Maw2432,

Thanks and yes, the copper is bare 22Ga wire.


@Conrad,

Thanks. I like the idea of using cans and old copper from wire to make a wet cell, should be simple enough to make a configuration of cells that will give you a decent amount of power. I also agree I need to work on finding just the right balance on the mixture used to increase efficiency and reduce waste like you said.

The thing I love about using the paper towel idea is that you don't have to use a lot of water to get good current out of a cell, as evidenced even the natural air carries enough moisture to power the cells, and when it dries one could simply store it for use another day and wont be constantly corroding all the time. In my early experiments with magnesium I learned first hand how fast water eats through it. With magnesium I think air batteries is the way to go to prolong its life.

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.

@Jeanna,

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.

Interesting experiment with the Al foil and graphite in sodium carbonate. Thanks for sharing, and yeah I'm sure a JTC would have really worked well.

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.  :D

@all,

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.

-Pete
« Last Edit: June 19, 2010, 08:33:44 PM by PeteIdl4 »

maw2432

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Re: Working Air Battery
« Reply #68 on: June 20, 2010, 02:26:11 AM »
@ all

Magnesium Firestarters   are available at Walmart for $7.00

Even less online....

http://www.vitacost.com/Coghlans-Magnesium-Fire-Starter?csrc=BRDC-056389078703

Bill

Pirate88179

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Re: Working Air Battery
« Reply #69 on: June 20, 2010, 03:34:44 AM »
The fire starter blocks are available at harbor freight for under $3.00.  If you can catch them on special, they are even less.

Bill

jeanna

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Re: Working Air Battery
« Reply #70 on: June 20, 2010, 03:46:40 AM »


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.


Quote
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.

Quote
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.  :D
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.



Quote
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

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Re: Working Air Battery
« Reply #71 on: June 20, 2010, 05:47:12 AM »
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

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Re: Working Air Battery
« Reply #72 on: June 20, 2010, 09:22:19 PM »
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

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Re: Working Air Battery
« Reply #73 on: June 21, 2010, 12:29:18 AM »
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

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Re: Working Air Battery
« Reply #74 on: June 21, 2010, 12:53:32 AM »
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.
« Last Edit: June 21, 2010, 01:33:00 AM by jeanna »