--- Gerald Combs gerald@ethereal.com wrote:
Leo Mauler wrote:
The "low cost dirt cheap" method would be to charge car batteries off a solar or other renewable grid ("bicycle power" is inadequate to the task of charging car batteries, though it might run a laptop) and use them with an inverter to run a laptop's conventional AC adapter.
According to one of the charts at http://www.minoura.jp/index-et.html, I'm putting out about 350W when I ride my trainer in the morning (for short periods, admittedly). My laptop's power supply puts out 72W.
The problem with bicycles as generators is that the human body really doesn't produce a consistent level of energy at the level to support an electrical device expecting a consistent level of power. Your bicycling will produce a rapidly fluctuating level of power, increasing the needs of the intervening power regulator.
Back in the days when I actually owned a bicycle (let alone one that would fit me) I had a nighttime light hooked up to a generator on my bicycle. It was only really useful as a signal light to let other vehicles on the road know I was there, because I could never maintain the level of power necessary to make the light bright enough to see the road. It was easier than remembering to purchase batteries for a battery-powered light, but I was dependent on streetlamps to see the road itself.
I'd expect a laptop hooked up to a bicycle DC generator through an inverter and the laptop's own AC adapter, to constantly fluctuate back and forth between the laptop battery and the AC adapter.
Those with more electronics experience might be able to rewire the laptop to use DC power directly, but stepping down the car battery to the laptop battery power level might require enough complexity that just an inverter with the existing AC adapter might be more workable.
My laptop takes 16 VDC, and automotive adapters are readily available. Couldn't you just use one of those?
Well, that was more or less my point. :)
Converting a laptop to be powered directly by DC current from a DC solar panel or other DC generator might be cool from a geek perspective, but a Rube-Goldberg machine from a practical standpoint.
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