This addresses 2 issues:
1. Input controllers report battery supplies.
That causes wrong charging status or capacities if they report percentages instead of levels.
Such supplies normally report scope attributes that report Unknown or Device type of power supply.
If reported value is System or the attribute is missing, it's considered a System supply and used.
2. Various systems have backup batteries.
That causes the wrong capacity to be reported depending on order of node creation.
This is addressed by keeping track of these and calculating an average.
86f8670d0b