Byron Jeff wrote:
> Correct. Which means that this works so long as the internal resistance of
> the battery is less than 1.5V/83mA = 18 ohms. Now if the internal
> resistance of the battery is more than that (like 9V batteries have high
> internal resistances) then you won't be able to get the 25mA out @ 5V like
> you want.
> <snip>
>
> Now the one thing you may miss in all of this is an effect called the
> Peukert effect. For batteries it simply states the faster that you draw
> energy out of the battery, the less total energy you can extract. So that
> 500 mA hr rating would be for a specific current draw for a specific number
> of hours, like a 20 hour rating for example. At 20 hours you can extract
> energy at a 25 mA rate. However if you extract it faster, then the amount
> of energy available goes down. For example at the 87 mA rate the capacity
> may only be 304 mA Hrs giving only 3.5 hours of operation at your example.
>   

Thanks a lot BJ, you're a great help. Give me a little while to mull 
things over and I'll probably be asking a question about the above 
paragraphs  :-D

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