While great in concept, solar powered gadgets just never seem to be very practical at the end of the day. Regen’s tweak on the formula might help a little, by stuffing a battery into the solar panel itself, meaning you don’t have to keep your iPod plugged in for a painfully long trickle charge or juggle multiple elements to make it work (there’s a USB plug on the side). ReNu also has batteries in its various docking accessories as well, all of which can be charged by the ReNu panel or by AC power