"Nico Coesel" wrote in message ...

Using a controller makes a lot of sense. I'm thinking about a PFC
scheme (about 25V into a big cap) and a forward converter-ish
output to drive a big LED. IMHO a battery is a bad idea. Better
use a big capacitor.

I have some 25 uF 2.7 VDC capacitors that could be used for this purpose.
Two in series would power a 3W 6V (12 ohm) incandescent lamp for a
time-constant of 12.5*12 or 150 seconds, although it would be much better to
use a boost converter and regulate the output so the brightness would be
more constant. Of course, you can get even more light from a 1 watt LED, so
even ONE of these UltraCaps would give at least 3-4 minutes of light without
needing the generator. These capacitors are only $5 each from Newark:
http://www.newark.com/illinois-capac...f-2/dp/02P4416.

Paul