Exactly, and since they state that they think they can make it twice as efficien... | Hacker News

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icoder on Dec 21, 2012 | parent | context | favorite | on: A $5 Lamp Powered Solely by Gravity

Exactly, and since they state that they think they can make it twice as efficient, that would mean they run at max 50% now.

duskwuff on Dec 22, 2012 [–]

I suspect it's even less than that. A fancy (= expensive!) bicycle hub dynamo has an efficiency of about 70%, and that's assuming that it's operating at peak efficiency, and that there are no additional mechanical losses in the lamp.

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