[Power] add aluminum / activated charcoal cells example about survivalmanual

[Siltaar]

Aluminum-air cells

Industrially produced "pure" aluminum allows to make more powerful cells. Aluminum / activated charcoal cells with salt water electrolyte produce 1V and 100mA with a 10cm by 10cm aluminum foil negative pole. Activated charcoal is usually used to filter aquarium water. Regular charcoal will be less efficient but better than a copper cathode (aluminum foil sized) which scores 10mA.

The drawback here is that aluminum is getting oxydated withing tens of minutes. Adding bleach to the salt water is helping preventing this.

[Siltaar]

Done.