Indicator doesn't use weighted average with different-sized batteries

[Allison Lortie]

The indicator implements the spec:

  https://wiki.ubuntu.com/Power#Handling_multiple_batteries

which stated:

  "Their percentages should be averaged."

Apparently this was taken to mean the simple arithmetic mean, and not the weighted average (by the capacity of each battery).

  http://bazaar.launchpad.net/~indicator-applet-developers/indicator-power/trunk.15.04/view/head:/src/service.c#L1316

shows:

  const double percent = sum_percent / n_batteries;

This means that if one battery is twice as large as another, then after that battery is discharged, 50% would be reported. I'd expect 33%.

The code needs to be fixed to reflect the more precise use of the word "average". <https://wiki.ubuntu.com/Power#multiple-batteries>: "Their percentages should be averaged, weighted by the capacity of each."

[Matthew Paul Thomas (mpt)]

Mea culpa. It never occurred to me that a device might contain multiple batteries of different capacities.

[Matthew Paul Thomas (mpt)]

Specification updated. <https://wiki.ubuntu.com/Power?action=diff&rev2=69&rev1=68>