AVR-Chat

> Do you absolutely have to use a 9 volt battery?  (I am
> assuming it is the square kind with snaps on the end).  If
> not, consider running your project from "AA" or "C" cells.
>


4 x AAA NiMH (or even 3 x AAA alkaline) cells would supply enough power with
the voltage within the range of the electronics, longer than a simple 9V
alkaline battery.

AAA NiMH can supply around 800mAh, at least 4 times what a 9V can do.

Considering a Dc-Dc converter, with a 85% productivity, it means that if you
will consume around 10mA @ 5V, it means 50mW, divided by 85% results in
59mW, divided by 9V results in 6.5mA.  So, your 9V @ 200mAh battery will
supply power for 30 hours, until exaustion.  Of course that this is a simple
calculation, current consumption increases with the battery voltage going
down, what accelerates the rate of discharge.  I would say 20 hours to be a
more conservative number.

Considering the 4 x AAA NiMH, 800mAh, direct connection, 10mA current
consumption, will give you around 70h of operation...


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