[Stoves] Hand Crank Dynamo for Fanned Stove?

[Niels Petersen]

Milliamps !   milli = 1000 Therefore 30 milliamps = .3 amp

Maybe you should reconsider your following statements

-- 
Kind Regards
Niels Petersen


On 12/5/07, Charlie Sellers <csellers42 at yahoo.com> wrote:
>
> Paul,
>
> If you really are pulling the full 300 milliamps (.3 amps) at 12 V then
> that amount of "power" is just the product of these two, or about 4
> watts.  For comparison a single ordinary LED will need MUCH less than one
> watt and the WoodGas stove fan needs a little more than 1 watt.  So your 4
> watt need is quite a bit of power.  Are you sure that your PWM duty cycle is
> 100%, and not less than that?  As you turn it up from no power to full power
> the duty cycle (or percentage of time that the PWM turns the power on) goes
> from 0% to 100%, increasing the fan speed proportionately.  An ordinary
> multimeter will not tell you duty cycle, so you can't use it to determine
> the power you are consuming.
>
> This got more complicated than I thought (so I deleted much of my
> discussion on LED circuits, units of measure, and calculating the energy per
> crank), but it was not a simple question.  The bottom line is what is the
> amount of energy that can be stored in the internal battery (voltage times
> the milliamp-hr battery rating) and how many cranks does it take to fully
> charge the battery?  Then determine how you will compensate for the lower
> voltage of the battery (perhaps much less than 12 V).  Some homework is
> required, and my gut feel is that all the LEDs in the latern take very
> little power, compared to 4 watts.
>
> My issue with solar battery charging and similar gadgets is that these are
> just more pricey parts to break when you are in a developing country - and
> the batteries themselves are just more parts to be diverted to other
> applications (like radios, then new rechargeable batteries may not be
> available to replace them for the stove).  I carry a slim 110/220 VAC
> battery charger with me, but fan stoves just may not be suitable for many
> places because they are somewhat high tech for now.  Cell phones at least
> are priming the world for small appliance and battery charging. Internal
> thermoelectric power is one approach to less parts, if a lifetime can be
> predicted when used in the field.
>
> Charlie
>
>
> "Paul S. Anderson" <psanders at ilstu.edu> wrote: Stovers,
>
> >> Jeff Davis wrote:
>
> >>> Found an interesting product at Harbor Freight. It's a hand crank LED
> >>> lantern.
> >>> Crank for 60 seconds and get 20 minutes of light.
>
> For the blower in my TLUD in India, I need 300 milliamps at 12 volts DC
> maximum
> power, and I "turn it down" with a PWM (pulse width modulator) that has a
> 500
> milliamps maximum.
>
> Question:  How many minutes of 300 milliamps 12 volt power can I get from
> existing hand-crank devices?
>
>
>
>
>
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