(PhysOrg.com) -- Although you can buy solar charging devices for rechargeable batteries, it would be even more convenient if batteries had built-in solar cells. Sitting in sunlight, the battery could then recharge itself.
Knut Karlsen, a blogger from Norway, hit upon this idea of a solar battery (a rechargeable battery with integrated solar cells) in hopes of making battery charging more convenient. He was able to work with some flexible solar cells given to him by the Institute for Energy Technology (IFE) in Norway. He then glued the 1.8V solar cells around some 1.5V NiMH rechargeable batteries. Using a conductive silver pen and some flat wires from a broken canon lens, he connected the solar cells and batteries.
Karlsen calls his DIY prototype "SunCat" batteries. As he explains, "The batteries should just bask in the sun like a cat and left for a while, in a sunny window, they would slowly recharge." However, according to his blog post, the weather wasn't sunny enough to test the batteries yet. He explains that the current set-up is not ideal, but a second version might include capacitors to charge the batteries more efficiently and electronics to show when the batteries are fully charged.
Explore further: Engineers improving safety, reliability of batteries