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Subject: Re: "Estimated Runtime" feature.

Re: "Estimated Runtime" feature.

From: Simon M. <simon.me_at_gmail.com>
Date: Tue, 17 Apr 2007 22:15:21 +0200

I don't know how the battery percentage and the runtime estimate are
coupled code wise.
If it is not a simple conversion, where the calculations for
percentages and runtimes (which are percentages of the max runtime)
are based on the same algorithm, then it would make sense to me to
keep the more accurate algorithm and convert the other display value
from that.

With most battery level displays (e.g. in mobile phones etc.) the
percentage drops faster when the battery is lower. To get from 100% to
50% takes much more time than from 50% to 0%.

I can learn how much time I have left with 40% battery, sure. But this
doesn't tell me anything I can rely on about my battery at 20% charge
(and I don't want to keep a discharge curve in my head, rockbox can do
that better for me)

If the current runtime calculation is better than a simple linear
voltage conversion, then I think we should keep it and use it for the
percentage display, too. On my iRiver, the estimate is quite good, I
suppose it can work equally good on portalplayer targets when the
current power issues are fixed.

I can learn how much time I have left with 40% battery, sure. But this
doesn't tell me anything I can rely on about my battery at 20% charge.

--
Simon (Rincewind)
Received on 2007-04-17

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