Green Daily

But...not affordable at all. At $0.10/kWh a $50 device is 500 kWh worth of power. Meanwhile, an ipod or cell phone has about a 700mAh battery (at ~3.6V). Multiply those two and the device has a 2.52Wh battery, so that means it would take about (500,000*60% / 2.52) = 120,000 charge cycles to break even (Energy Star chargers are only 60% efficient). Now the real problems start. This device uses an internal 1200mAh battery to store charge. Lithium batteries degrade capacity over time, so you really only expect about 4 years before the cell is dead. 4 years is only 1460 days, so unless you're going to charge a device 8 times a day, you'll never break even. It gets worse: that $50 is probably just for the hymini part, which is just the battery and wind turbine. Solar collectors are separate, and you'd probably want all 4 of them because they're kind of wimpy at 140mA each.

Given the long, long payback just in terms of money, I have to wonder about the carbon footprint of the plastics and silicon processing that go into making this and if you stacked that up against the amount of power a typical ipod user would actually consume in the life of the device, I bet it comes out net negative.

I like the idea, but it's not practical at this kind of price point. If you buy it, it's a toy. This "green math" can be tricky business. :-/

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