HOW TO: Wipe Battery stats to improve battery life

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coming form other android phones, ive learned to wipe batt stats in recovery to get the best life.
normaly i wind up seeing voltage @ 100% a little over 4.260v

now on our phones we dont have that option, and i noticed while trying out diferent roms that its hitting " 100% " at various voltages depending on what the batt truely was when flashing.

if i recall the file is : /data/system/batterystats.bin that we need to delete? corect?

well, before i did it, it hit 100% @ 3.782v and wouldnt go any higher...
now, im sitting @4.246... im not 100% sure its fully charged. ill let it sit overnight turned off and see where i wind up.


UPDATE 11-20
SO, voltages have been confirmed.
100% = 4.20-4.25 depending on battery condition
0%= dependent on the kernel generaly 3.2-3.0 {found some as high as 3.7v!} thank you to hastarin for pointing the files out

if your not seeing 4.2v your not getting full battery life.

sure enough, i was sitting just shy of 4.3v this am after an overnight charge with the phone turned off...

Interesting info, but where would you find out the voltage the battery is producing?

so, how to wipe the battery stats?

time to get down and dirty and learn to navigate thru the android OS.
download and set up the android SDK
http://developer.android.com/sdk/index.html

heres a newbie guide to adb in the nexus forum
http://forum.xda-developers.com/showthread.php?t=619153

for those less computer literate, you can use droid explorer to do alot of the stuff thru a GUI. it also will set up adb for you.
http://de.codeplex.com/

the code that you type in to remove the battery stats is

rm data/system/batterystats.bin

now to properly condition the battery.

turn off the phone, plug it in, preferably overnight.
boot the phone up while still pluged in.
delete the batterystats.bin file ether thru adb or terminal
drain the battery fully, untill it powers down. wait a min or two and reboot it to completely drain it.

congrats... your phone now knows corect voltage values for 100% and dead.


Remember: Flashing a new Android build erases the battery stats, and automaticly rebuilds them based on voltages it see's .

ie: you need to recondition after each flash to get max battery life.

i use the "battery life" widget by curvefish to show me temp, voltage etc.

Originally Posted by Slampisko

Interesting info, but where would you find out the voltage the battery is producing?

some builds will show actual voltage under menu/about phone/battery use

otherwise i use the " battery life" widget by curvefish, available for free from the market. once you add it to the screen, tap it, hit settings, then check both charging info and extended info.

after conditioning the battery, im currently @27 hours since unplugging, gps, and wifi turned on the entire time, im @ 3.873v or 61%! granted, its been light usage its my secondary phone right now, but i am on the outskirts of service, and the week signal usualy sucks the battery...

ill update again , probably this time tomorow once it finaly dies...

just a little food for thought: its been over 27 hours since i unpluged, and my voltage is still higher than what the phone assumed was 100% @ the time of the initial flash....

@ 50 hours (still 10%) i finaly got sick of waiting for it to die. i turned screen on full bright, and ran gps test and locked the screen on. phone finaly died @ 2.988v im now charging it again with the phone turned off.

Umm why do we need this though ?
Wont the phone keep running as long as there is sufficient voltage in the battery ?

What is the use of this method ?

This is for people who have found a build they are happy with and want to use for a while so that their battery lasts longer, much longer. As the OP has posted, his phone is currently lasting about as long as it does in WinMo which is an impressive feat, more so being as he's running his GPS non-stop at the same time.

I for one am going to do this myself when I get the time. If I knew whether my alarm would go off while the phone was switched off (for the overnight charge) I'd do it tonight but cannot risk being late for work tomorrow lol

Thanks Reno but I meant HOW does it work ?

I thought this method just helps you see your battery's percentage .. Wont the battery run no matter what the percentage show as long as the battery has a charge ?

Can someone please explain this ?

Yeah I cant afford not waking up late as well, so im charging it while its on, would that affect anything ?
It will still charge up the battery wouldnt it ?