Solar batteries recharge without electric power

These are still prototypes, but the concept is innovative. Instead of recharging batteries by putting them in a recharger attached to an electrical outlet, these batteries would recharge when they are placed in sunlight.

Karlsen’s SunCat batteries circumvent chargers completely by integrating solar cells within the batteries themselves. To make these prototypes he attached 1.8V flexible photovoltaic cells onto 1.5V NiMH rechargeable batteries and connected them with a conductive silver pen and a few flat wires. The effect is similar to a trickle charger, which slowly charges a battery and can be left attached indefinitely without overcharging.