Comment 7 for bug 811777

The summary of this bug report says "'Show Percentage Remaining' is more useful than 'Show Time Remaining'". As far as I can tell, though, this bug report does not contain any evidence for that, and doesn't even contain any evidence that showing the percentage is useful at all. For that reason, I'm marking it Incomplete.

Without that evidence, I believe that battery percentage -- while easy for a battery to report, and for an OS to display -- is pretty much useless to humans. For example, on the 2008 MacBook running Ubuntu that I'm using right now, 98% means about 2 hours remaining. On my 2011 MacBook running Mac OS X, 98% means about 10 hours remaining. That's a fivefold difference in how long I can use the computer, represented by exactly the same percentage value.

It may be true that on some machines, the time estimate changes too much and/or too often to be useful either. If so, then as Vish and Ted have suggested, that is a fixable bug. (Sample from more minutes, and/or give less emphasis to recent changes in the charge level, and/or cater for old batteries by reversing the charge curve from the previous cycle.) Making the time estimate less prominent would not fix that bug. And showing the percentage would not improve the situation at all -- because in the absence of a time estimate, your brain would be estimating the time based on the rate of percentage decline, and that rate would be fluctuating exactly as much.

Percentage might be interesting to someone troubleshooting a battery problem, or investigating whether a battery is worn out. So it is useful to show it in the Power Statistics window, where it already is. I would be happy to help anyone who would like to make that window more understandable.