Magnesium graphite homemade battery. The human race has come a long way with technology, and in some ways we rely far too much on that technology. This is evident during a power loss when habit kicks in and we still reach for a light
switch or a other electrical appliance.
I have always been interested in creating my own power and this is another example of a homemade battery. It exploits the potential voltage difference between two dissimilar metals and the oxidation and reduction that takes place when they are connected. You can find potential voltage difference charts easily on the Internet, and I did this when creating a copper/zinc battery.
I noticed that magnesium was at one end of the spectrum and graphite at the other. While carbon was an easier choice in terms of how long it would last I found that graphite gave a better output. I promptly ordered several graphite part pencils from an art shop. Unfortunately they arrived broken to pieces with only a couple surviving intact. These are almost pure graphite and are quite soft and water soluble. Not the best components for a battery that needs to be moist but they gave me a great output.
The magnesium comes in the form of a ribbon rolled up. Magnesium is extremely flammable however the flashpoint is quite high which means you can solder wire to its quite easily, but if it ignites you will know all about it.
Graphite heart pencils
Chamois or other of absorbent material
Chamois is a highly absorbent treated leather used to dry off cars after washing. Strangely I got far better results using a natural Chamois rather than a synthetic one. These were cut into pieces the same length as the pencil and wide enough to wrap around the graphite once. Each link needs to be slightly wider than the previous as the diameter increases with each wrap.
I stripped the paper from off the graphite stick. Wrap one length of the material around the graphite stick and use the sport tape to secure it. Sports tape holds up well in moist conditions. Take the magnesium ribbon and secure a 1 inch to the bottom of the stick and begin wrapping it around in a coral configuration that does not overlap. Make sure none of the graphite is touching the magnesium. When you reach the top, leave a length of ribbon extending out from the top. Take another strip of material and wrap it around the magnesium leaving the long strip of magnesium at the top protruding. Secure this using the sports tape. Wrap the magnesium ribbon around once more leaving another piece protruding from the top that will join up with the previous one. Now wrap another layer of the material around the outside of everything and secure it in place.
You should now have the graphite stick wrapped in material, then graphite, then material, then graphite and the last layer of material. None of the magnesium should be touching the graphite and the two protruding strips of magnesium ribbon touching each other at the top. You can test the voltage of the cell by wetting it down and using a voltmeter with the red on the graphite and the black on the magnesium. Myself produced around 1.9 volts.
The image is shown here consists of my graphite magnesium battery running a light emitting diode after going through a small circuit called a joule thief. You can find the schematic for this circuit online. I also show the battery powering a small magnet motor which shows that it has enough potential energy to push around mass.
I have since found that although the graphite gives a better voltage it does not last for very long time if it is continually moistened as the graphite is water soluble. Carbon rod may be a better choice as it will last much much longer but give a slightly smaller voltage.