hand powered linux box

[Leo Mauler]

--- Gerald Combs <gerald at 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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