[ltp] Re: [PATCH v2] Re: Battery class driver.
Pavel Machek
linux-thinkpad@linux-thinkpad.org
Thu, 2 Nov 2006 23:01:45 +0100
Hi!
> Well, "Wh" measures energy and not power, and "Ah" measures electric charge
> and not current, so it would be better to make that:
>
> capacity_*_energy (Wh-based)
>
> and
>
> capacity_*_charge (Ah-based)
>
> Also, should we go with mWh/mAh, or with even smaller units because of the
> tiny battery-driven devices of tomorrow?
Okay... So I have cellphone here, 700mAh battery, ~2.8Wh battery. It
could last 14 days if we were *very* careful.
echo '(700 mA * hour) / (14*day) \ A' | ucalc
ucalc> OK: 0.002083
ucalc>
...that is about 2mA in low power standby mode (but still listening on
GSM, getting calls, etc).
...so, mAh are probably good enough for capacity_*_charge, but would
suck for current power consumption, as difference between 2mA and 3mA
would be way too big. We need some finer unit in that case.
Pavel
--
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