# Home grown battery **URL:** \ **Category:** Factual Questions\ **Created:** [November 15, 2000, 7:31am UTC](https://boards.straightdope.com/t/home-grown-battery/41278 "2000-11-15T07:31:50Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![EvilGhandi](https://avatars.discourse-cdn.com/v4/letter/e/f17d59/32.png) [@EvilGhandi](https://boards.straightdope.com/u/EvilGhandi)\ **Post date:** [November 15, 2000, 7:31am UTC](https://boards.straightdope.com/t/home-grown-battery/41278/1 "2000-11-15T07:31:50Z")
Why didn’t this work? I attempted to build a simple battery as a learning project for the kid. It was constructed as follows. I poked two holes into one of those MM candies tubes about 1 cm apart. I shoved a length of 10 ga copper wire into one of the holes and a 10 d galvanized nail into the other. I tied them at the base with a piece of rubber to keep them about 1 cm apart but not touching. Then I filled the tube with a vinegar and salt solution to serve as electrolyte. After the device stood for about 10-15 minutes, I tested it with a multi meter. You guessed it, nada, zippo, not even a microvolt. Any clues as to why I didn’t generate even a little current? Could it have to do with the fact the zinc is layered over steel on the nail? Could my elctrolyte just be too weak? Mind you this is a nine year old, so concentrated solutions of sulfuric acid are out. ---
**Author:** ![Zor](https://avatars.discourse-cdn.com/v4/letter/z/848f3c/32.png) [@Zor](https://boards.straightdope.com/u/Zor)\ **Post date:** [November 15, 2000, 9:22am UTC](https://boards.straightdope.com/t/home-grown-battery/41278/2 "2000-11-15T09:22:28Z")
Is the salt you’re using table salt? If it is, it won’t work, because you’re getting sodium ions with a very low redox potential. Try to find a salt that will give you iron, nickel, copper, or silver ions. You also need a salt bridge to separate the two solutions your terminals are immersed in. Placing both terminals in the same solution is a bit like short-circuiting your battery. ---
**Author:** ![matt](https://avatars.discourse-cdn.com/v4/letter/m/a6a055/32.png) [@matt](https://boards.straightdope.com/u/matt)\ **Post date:** [November 15, 2000, 10:07am UTC](https://boards.straightdope.com/t/home-grown-battery/41278/3 "2000-11-15T10:07:42Z")
You should be able to measure a voltage, even if the current the thing can supply is pathetic. If you are literally getting “not even a microvolt” then your copper and your nail are being shorted somehow - either they are touching despite your precautions or your external connections are wrong. (Or something weird is happening, like a foil layer in the tube is shorting the two together.) As an alternative, try stickng your nail and your copper wire into a lemon. Fewer construction problems,and it should work just as well! ---
**Author:** ![Inky\_1](https://avatars.discourse-cdn.com/v4/letter/i/7feea3/32.png) [@Inky\_1](https://boards.straightdope.com/u/Inky_1)\ **Post date:** [November 15, 2000, 3:34pm UTC](https://boards.straightdope.com/t/home-grown-battery/41278/4 "2000-11-15T15:34:30Z")
Another thing to try is using a nail made out of zinc. They’re available at any hardware store and would make a better anode. ---
**Author:** ![Meephead](https://avatars.discourse-cdn.com/v4/letter/m/b782af/32.png) [@Meephead](https://boards.straightdope.com/u/Meephead)\ **Post date:** [November 15, 2000, 4:54pm UTC](https://boards.straightdope.com/t/home-grown-battery/41278/5 "2000-11-15T16:54:42Z")
The zinc nail is a good idea, but the steel one should work also, especially if it is galvanized. Try losing the salt in your electrolyte solution. Salt makes your electrolyte more conductive, IIRC, thus a lower voltage will be produced. Additionlly, I believe that it increases the pH, and therefore the effectiveness of the vinegar. The vinegar alone should work. Matt beat me to the punch (lemonade, anyone?:D) with the lemon idea. ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [November 15, 2000, 5:43pm UTC](https://boards.straightdope.com/t/home-grown-battery/41278/6 "2000-11-15T17:43:01Z")
Another thing to consider: it may be producing a voltage, but the equivalent source impedance may be very high for some reason. To check if this is the problem, measure the voltage with a digital volt meter (as opposed to an old fashion analog one). Digital volt meters usually have very high input impedance, and thus draw very, very little current from the source. ---
**Author:** ![Inky\_1](https://avatars.discourse-cdn.com/v4/letter/i/7feea3/32.png) [@Inky\_1](https://boards.straightdope.com/u/Inky_1)\ **Post date:** [November 15, 2000, 6:06pm UTC](https://boards.straightdope.com/t/home-grown-battery/41278/7 "2000-11-15T18:06:14Z")
Not trying to hijack the thread or anything, just wondering why a galvanized nail would be any different than your typical iron nail? The increased carbon content? Does the sulphur content in lesser grade steel retard the process? ---
**Author:** ![Meephead](https://avatars.discourse-cdn.com/v4/letter/m/b782af/32.png) [@Meephead](https://boards.straightdope.com/u/Meephead)\ **Post date:** [November 15, 2000, 7:48pm UTC](https://boards.straightdope.com/t/home-grown-battery/41278/8 "2000-11-15T19:48:25Z")
> [@](#): > > \*Originally posted by Inky- \* > \*\*Not trying to hijack the thread or anything, just wondering why a galvanized nail would be any different than your typical iron nail? The increased carbon content? Does the sulphur content in lesser grade steel retard the process? \*\* The zinc coating on a galvanized nail help prevent it from rusting (the original reason it was galvanized). In simple terms, a byproduct of this zinc coating is that it makes the nail a better candidate to use as the negative battery terminal–almost as good as a solid zinc nail. I don’t think that the sulphur and carbon are much of an issue. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [November 15, 2000, 8:22pm UTC](https://boards.straightdope.com/t/home-grown-battery/41278/9 "2000-11-15T20:22:19Z")
You Need: Pennies Nickels Paper Towels Vinegar Rip the paper towel into squares a bit bigger than a nickel. Soak the paper towel squares in vinegar. Alternate penny, paper towel, nickel, paper towel, penny, paper towel, nickel, etc. The longer the string of nickels and pennies the stronger the battery. Hookup your voltage meter and bingo-bango – instant battery. It’s easy too and your money is still good, if stinky, afterwards. ---
**Author:** ![Nukeman](https://avatars.discourse-cdn.com/v4/letter/n/ce7236/32.png) [@Nukeman](https://boards.straightdope.com/u/Nukeman)\ **Post date:** [November 15, 2000, 11:14pm UTC](https://boards.straightdope.com/t/home-grown-battery/41278/10 "2000-11-15T23:14:03Z")
jeff took the words right out of my mouth, except i was going to suggest circles of paper towel soaked in (i think) lemon juice followed by layers of tin foil and so on ---
**Author:** ![EvilGhandi](https://avatars.discourse-cdn.com/v4/letter/e/f17d59/32.png) [@EvilGhandi](https://boards.straightdope.com/u/EvilGhandi)\ **Post date:** [November 16, 2000, 8:27am UTC](https://boards.straightdope.com/t/home-grown-battery/41278/11 "2000-11-16T08:27:00Z")
I 86ed the salt from the electrolyte solution. Yippie I got a reading of .06 volts. Your suggestions have given me some ideas as well. Next I plan on securing a stack of copper flashing sheets and a stack of galvanized sheets from the home center. Any suggestions on how I should construct this baby? My plan is to coil the sheets into cylinders and place one inside the other, seperated by rubber o rings or maybe just plain ol rubber bands. Then I will immerse the plate combos into jars of whatever electrolyte I decide on and daisy chain them annode to cathode until I get some appreciable voltage.