Jump to Navigation

How estimates are calculated

1. Global Estimation

This is the weighted average between #2 and #3 below.

2. using all-time average

This is based on average times of AC, USB and unplugged cycles.

3. using average since (un)plug

This is based on last measures

4. using battery (dis)charge

This is based on current mA charge/discharge and remaining battery capacity (mAh).

Let's consider the following situation:

    • Current battery level is 90%
    • Last measure shows 100%, 10 minutes ago (1% per minute)
    • Average discharge time (100->0%) is 20 hours (5% per hour)
    • Current mA = 50mA and mAh = 1350 (full=1500mAh)

This results in the following figures:

    1. 10% 1h30m + 90% 18h = 16h21m
    2. 90% to go at 5% per hour = 18 hours
    3. 90% to go at 1% per minute = 1 hour 30 minutes
    4. 1350 mAh / 50 mA = 27 hours

When you use your phone as an usual day, you can estimates the time remaining based on previous usage, eg the average time from 100% to 0% that was previously recorded.

That's the all-time average estimate.


Now let's say you've unplugged fully charged and your using the phone from time to time in a regular way, you can then estimates the remaining time on battery from the usage since unplugging the phone.

That's the since-unplugged average estimate.


But now, let's say you're starting to play a 3D game and it's consuming a lot, you can estimates the remaining time playing this game using battery consumption (mA).

That's the battery drain estimate.


So now, the global estimate is the weighted-average between all-time and since-unplugged estimates. The weight is the actual %-based.

The closer to 100% the more global estimate is close to all-time average. The closer to 0% the more global estimate is close since-unplugged average.

I replaced Stock battery on a Photon 4G (1650MAh) with a 1950 mAh and got Battery Monitor widget to calibrate.  BMW behaves very strangely.  It seems to drop too fast initially and never report the 'about to die' event properly.

Fight now, after charging all night, it reads 1911/1950 mAh and 26°C/4036 mV which sounds like it should be correct, but that's only with a few minutes running.  Also, on idle the graph is very erratic, dropping and then plateauing, and then dropping again.  In a few minutes it's now reading 1891/1950mAh.

Also,. what should be the bottom of the scale in mV?  I seem to see it at 3200 when it dies.  Is this rational?

That's the minimum voltage most battery will accept before considering it's empty.

Did you enable the '% based on mV' in the monitoring settings? If not the % you read are provided by Android. If you have this option on, it will only help about measring the real 0%.

As for the 'about to die', it's not an app alert, but an Android alert based on the % reported by Android, which is the default you can see in the app when above option is off.

Main menu 2

Forum | by Dr. Radut