> Hi Mike,
>
> Say that two alcaline penlight cells have a capacity of 3000ma/h.
> You don't want that 3A over one hour but only 0,5ma during X hours.
> 3000/0,5 = 6000 (x 1 hour). Which is ca. 250 days, or ca 10 month,
> before the cells are empty. And empty is about  1.3v each.

        While that makes "math sense" in the real world that just isn't that useful
a technique. The reason is the "capacity" of a battery is dependant on the
load. Some batteries are far better at handling smaller loads over long
periods of time then others "i.e. alkaline vs. nicad).

        Therefore, while a battery may state 1000mAh, that does NOT mean it can
supply 1mA for 1000 hours. What it means is usually the bit of information
that's left out of a quick spec: the load current where you get that rating.

        The ONLY ways to realistically get good numbers is either to spec the
SPECIFIC battery (from the manufacturer) or to do real world testing.

        Oh, and on top of all of this, the capacity of a battery is dependant on
more then just current, most batteries are VERY dependant on temperature,
age is also a very important figure, as is number of discharge cycles. TTYL

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