[Stoves] Hand Crank Dynamo for Fanned Stove - Success!

[Charlie Sellers]

Well said, I have done this - it worked because it was indeed a powerful Philips LED with 3 cheap 1300 mA-hr NiMH batteries so perfectly matched to the WoodGas stove fan - and will post the detailed results soon (initial testing of battery lifetime is tedious).  Sorry to doubt you Paul, you just need the right crank light, with a good quality dynamo inside - and I had a broken one, for experiments, and a good one to hack.

Charlie

"David G. LeVine" <dlevine at speakeasy.net> wrote: At 06:49 PM 12/4/2007, you wrote:
>Which part should Charlie reconsider? Looks to me as though he 
>calculated the power requirement correctly, but perhaps I'm missing something.

I just looked at three "muffin" fans (computer fans.)  They were "5V, 
0.55W" or 0.11 Amperes, "12 Volt, 0.08 Amperes" and "12 Volt, 0.12 
Amperes"  Now, a typical LED runs about 3.5 Volts for white and can 
be in the 20 mA to 1,500 mA range.  The 3 LED flashlight is PROBABLY 
running either no more than 10.5 Volts OR has a complex 
driver,  Since NiMH batteries are 1.25 Volts, there must be at least 
9 of them to drive the LED OR there is a "boost" power supply.  A 
good flashlight these days runs 1 Watt, 1 Watt at 9*1.25 is 0.088 
Amperes/88 mA.  That says that the middle sized fan should give 
similar results to the LED lights.

Will it work?  I dunno ...  Is it possible?  Yes, take a 
flashlight apart and see what is inside.


David G. LeVine
Nashua, NH  03060


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