Your customers might want a bit of incentive to start using a solar battery charger-- that's the philosophy behind Changers offering social networking and reward incentives with the Changers Starter Kit.
The charger consists of a rechargeable battery (a 2x 3.7V li-on cell with 16 Wh capacity) and solar panel combination. Changers says fully charging the battery takes around 4 hours, and is compatible with any USB-enabled device.
The software and social networking make it more interesting-- the device records the amount of solar energy users collect and converts it into Changers Credits redeemable into (yet unannounced) rewards.
One can also boast about the amount of solar energy collected via community and Twitter functions.
Pre-orders for the Changers Start Kit are already open, with shipments to start on November 2011