An other cell based on Pete's (PeteIdl4) aluminium - copper wire cell:

Because I like the aluminium - salt water paper - copper cell (the materials are easy to obtain) I built another one.

This time I used a copper sheet (instead of the copper wire) and an aluminium sheet (instead of soft drink cans) to see if that works better. The paper was soaked in 10% salt water (10 grams salt in 90 grams tap water). The metal sheets are 60 x 90 mm (rather small).

It seems that a "press mechanism" provides higher amperage, therefore I built four cells which are tightly pressed together.

This design also allows rapid assembly and disassembly (in case one wants to change the paper or check corrosion on the metal sheets).

Results with four cells in series:

no load 2.6 Volt (4 x 0.65 Volt)

3 mA load 1.6 Volt (4 x 0.4 Volt)

7 mA load 1.2 Volt (4 x 0.3 Volt)

10 mA load 1.0 Volt (4 x 0.25 Volt)

short circuit current is up to 25 mA


7 to 10 mA (at 1 to 1.2 Volt) are enough to drive a Joule Thief with a few white LEDs. For instance one could build a flash light (for use at home) with such a "battery". It should take a very long time till the copper and aluminium are corroded (may be years). Water has to be added occasionally. And may be the paper has to be changed every few months because it might fall apart.

Of course, one could build much better batteries with other materials (graphite, zinc, magnesium and some acids), but the goal is to build a very simple battery with materials commonly available (or from materials which are often thrown away like soda cans and old cables or wire from torn down buildings).

My next attempt will be a steel - damp salt paper - copper cell.

Greetings, Conrad

Hello Everyone,

Vids have been uploaded regarding the 3 water battery experiments in case anyone is interested. The vids show a progression, ending at the third experiment with the tiny 1 inch by 1/8 inch units producing 3- 3.5 volts  each without any Joule thief or acid, just tap water and enough current to run super bright LEDS.

Blessings,

Littlechristgod

@ rock321

Could you tell us where the "vids about your water battery experiments" are to be found?

A link would be great.

Greetings, Conrad

Salt paper can absorb the ambient humidity, which could very likely shorten the battery's life.

Quote from: conradelektro on July 01, 2010, 01:56:08 PM
Replication of Pete's (PeteIdl4) aluminium - copper wire cell:

See Pete's tutorial videos (and my photos below):
Part 1 http://www.youtube.com/watch?v=B9YqFY-Z0dk (video by PeteIdl4)
Part 2 http://www.youtube.com/watch?v=ZeQof7ue9xA (video by PeteIdl4)

- Kitchen paper towel sheets were soaked in saturated salt water and then dried in the sun. They were a bit stiff after that but that helped when rapping the paper over the inner aluminium sheet and over the copper wire windings.

- When winding the wire over the (paper covered) inner aluminum sheet I took care that the windings did not touch.

- The outer aluminium sheet and the inner aluminium sheet are held together by a little screw which also holds the cable to the aluminum.

- Air can enter the cells from three sides.

- Four cells are connected in series to get about 2 Volt (without load)

- After the cells were finished they showed about 0.5 Volt, but almost no current. So I added a little water with a pipette. Just enough to make the paper damp. After that I am getting great results (almost for three hours till now):


0.5 Volt without load

0.4 Volt with 1 mA load

0.2 Volt with 4 mA load

short circuit current is about 6 mA


I will report in the coming days how the four cells are holding out. They are driving a Joule Thief which draws about 1 mA (while the four cells in series hold 1.6 Volt steady).


@ Mk1 - Thank you for the aluminum cell PDF-document!


Greetings, Conrad

Here's the link: http://www.youtube.com/Littlechristgod#p/u/2/JU5R9511CGg

Blessings,

Littlechristgod