We have a way to import battery levels for the end user now
First time you run battery bench the current battery levels will be exported as
battery_levels.default
Set your device up as you normally use it and set a playlist to play on repeat with the same formats of the songs you generally listen to (mp3 flac etc)
now run battery bench till the device dies (maybe do this several times and average the results to get really precise)
now alter
battery_levels.default
with your new voltage values and rename it to
battery_levels.cfg
https://www.rockbox.org/wiki/PluginBatteryBenchmark.htmlan example of the defaults from my clip zip:
# Rename to /.rockbox/battery_levels.cfg
# Sandisk Sansa Zip Battery Levels (f93982349bM-250112)
# Battery voltage (millivolt) lower than this won't access the disk to write
disksafe = 3400
# Battery voltage (millivolt) lower than this player will shutdown
shutoff = 3300
# Battery voltage (millivolt) of 0%, 10%, ... 100% when charging disabled
discharge = { 3300, 3653, 3701, 3735, 3768, 3790, 3833, 3900, 3966, 4056, 4140 }
# Battery voltage (millivolt) of 0%, 10%, ... 100% when charging enabled
charge = { 3427, 3786, 3842, 3877, 3896, 3924, 3971, 4028, 4084, 4161, 4190 }
I wouldn't mess with the
disksafe level if you are NOT using solid state storage
Also you shouldn't change
shutoff unless you know what you are doing and the underlying battery chemistry,
as most devices will still shutoff anyway and the ones that don't will likely damage the battery if you set it too low.
basically you will take your battery bench results and map them to the 0-100 of the battery level to get a more accurate display of battery capacity
https://download.rockbox.org/daily/manual/rockbox-ipod6g/rockbox-buildch12.html#x19-33600012.4.2