In February the Pee Powered battery was in the testing phase in Japan. Now it would seem they have made it to the store for the Japanese to buy and use. NoPoPo (Non-Pollution Power) Aqua Batteries are available in both AA and AAA form.
Weirdasiannews reports that although the company page shows they are producing the technology for all sizes of battery, they can only be currently purchased in Japan.
The idea here is that the batteries can be recharged with various different fluids, using the new technology which forms electric power using liquid as a catalyst.
The basic principle is that a mixture of magnesium and carbon reacts when mixed with a liquid to produce, in the case of the AA battery, up to 500 milliamp-hours (mAh) of life.
Urine contains many ions (electrically charged atoms), which allows the electricity-producing chemical reaction to take place in the urine battery.
Every time the battery gets recharged it has a lower power level than the time before and the life cycle allows for about 3 to 5 recharges before disposing of the battery. Potentially, each battery can keep its charge for up to 10 years which could be great for many life saving devices in remote locations, or other applications.
The batteries do not contain mercury and other harmful materials, so they can be easily disposed of without worry for the environment.
So, need a recharge? Just pee on them and you're all set.