Hello. Does anyone know where to find a robot solar battery charger? I would prefer to find a lithium polymer solar battery charger.
And just to be a bit picky, it would also be nice if the charger had a digital output so that it can indicate to a microcontroller that sun and/or battery power is low.
If the battery is low, have the robot rest a bit and charge up in the sun. If the battery and sunlight is low, have the robot hide and await pickup.
Please help! USB would also be another wonderful option!! 
My email is lostinsocorro@gmail.com in case one of you happen to already have or have thought of a circuit design. Thanks.