With that information in hand, he set out designing his light, finding a contractor in China to manufacture the resulting circuit board.This will likely be discussed further in an upcoming piece in response to the Gates Foundation "Myths" annual letter.
For batteries, Lule simply chose three AA NiMH rechargeable, which are typically good for 12 hours of lighting. Those are expensive in Uganda at the moment but relatively cheap to import since they're mature technology. He estimates they'll be good for two years of use; by the time that's up, he hopes to be able to sell replacements to his customers. There's also nothing special about the LED itself or the solar cells. "I found people online, and I basically gave them the specifications, and they made the solar panels," Lule told Ars. "I've discovered that, if I buy just the solar cells and make the solar panels myself, I'll be able to save $0.80."
(17 years of informed commentary)