Battery Calibration

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Having seen so many posts on calibration of battery, i have decided to make this thread so to make it easier and useful for you guys. This thread can also be used to share your experiences with calibration and usage of milestone's battery.
Note: This is done using a the motorola milestone 1. So if you're using any other phone, pls ask abt them in this thread b4 you do anything!!!!

The calibration of the battery is needed when you want to switch/install roms. This will make sure that the battery is really fully charged, thus preventing the battery life from dropping too drastically in a matter of hours.

I know there are some other methods to help calibrate your battery, but this is the only one I am sure of the steps. Please inform me of the other methods so to share with everybody.


1. Before flashing a new rom, use root explorer (with read/write set) to delete the file "batterystats.bin" stored in /data/system/.

2. Charge your phone with it being turned off.

3. After it is fully charged(100%), take out its battery without plugging off the power supply.

4. Wait for a few moments, and a ? sign will appear.

5. Put your battery back in. You should see that the battery percentage increases quickly to 60%. If it increases to 100% with seconds, please skip to step 6.

6. If it stops increasing at 60%, let the phone continue to charge until 100%(takes quite a while)

7. Once it reaches 100%, let it charge for a further 15-20 minutes.

8. Once that's done, you can boot to OpenRecovery and flash your rom!!!

Alternative way of calibration(thanks a lot zeppelinrox!!!):

This method allows you to calibrate the battery and use ur phone at the same time!!!

I hope this helps you people, because it really helped me!!!!
Note: i m not responsible for anything bad that happens to ur phone. Perform the calibration at ur own risk!!!(though it should be perfectly fine, unless u do something wrong or extra)
Btw, i am just writing things that i assume to be correct, so if anything needs to be edited/added, pls inform me through this thread or sending me a pm.

Credits to everyone (especially pcphobic for his post in who have written all these in your posts that made it possible for me to gather and get all this info!!!!!!
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3rd March 2011, 10:26 AM |#2  
BryanChung's Avatar
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You should give credits to whom you copied this from.
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3rd March 2011, 12:09 PM |#3  
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oh yea i almost forgot.Thx fellow citizen!!!!
3rd March 2011, 12:11 PM |#4  
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And it's good to remove/wipe the battery status data with the charger plug-in as the last step.
3rd March 2011, 12:16 PM |#5  
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thx bnwg, but i don't get you. Mind if you make yourself clearer? Thx!!!!
3rd March 2011, 12:22 PM |#6  
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Originally Posted by nickrule1896

thx bnwg, but i don't get you. Mind if you make yourself clearer? Thx!!!!

He's referring to deleting the batterystats.bin file from the /data/system folder.
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3rd March 2011, 12:24 PM |#7  
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Yup, got it thx!!!!
3rd March 2011, 12:30 PM |#8  
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mount -a
rm /data/system/batterystats.bin

For this set of instructions, can the console in the OR be used to perform it?
3rd March 2011, 01:38 PM |#9  
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mods should make this thread a stickie.
3rd March 2011, 01:39 PM |#10  
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Calibrating Without Downtime!
Edit: If this doesn't work on your device, try the Die-Hard Battery Calibrator Script to ensure a proper charge

This is proven to work with Motorola Milestone so I would imagine the Droid as well.
It works with the Milestone 2 but you may need to get the phone booted up manually (step 7) instead of the easy reboot in step 6.
If you have a different phone and this works, please let us know!

You probably won't believe that this will work but try it anyway.

The big benefit of doing it this way:
It's great if you don't plan on changing roms and just want to calibrate your battery without downtime so that you can just use your phone as you normally would.

Note: Be sure that the phone isn't running hot (feel the back)

1. While in Android, charge up to 100% and leave the phone plugged in.
2. Delete /data/system/batterystats.bin
3. Remove back cover
4. Press Power and choose to reboot normally.
5. When the screen goes black and the lights go out, pull out the battery before you get the M logo. It will probably still work after the M logo shows up but that's how I do it.

6. Surprise: The phone will boot up without the battery! - Mine does - every time

Note: Batterystats.bin is recreated when you see the M logo - even though the battery isn't in the phone.

Go to Step 8 if the phone booted up as described.

7. If it doesn't boot up and you see the battery with the ?
..........a) Put the battery back in (you will see 60%),
..........b) Power off the phone (press power until LED light goes out)
..........c) Power on the phone (press power until you see the M logo)
..........d) Remove battery... and watch bootanimation...

8. a) After the surprise of seeing the boot animation without a battery, you will then see the lock screen along with a "No SIM card error" and no signal.
...... Put the battery back in - the SIM card error will disappear, you will get a signal, it will show 60% full and the icon will show the battery charging.
...... Go to Step 9 if this works as planned. If it doesn't, reboot (again without the battery) and use step 8b instead of step 8a.
... b) Put the battery back in during the bootanimation, but after the haptic feedback/vibration (and the buttons along the bottom light up).
....... On a normal reboot, you can actually slide and unlock the phone when you get the vibration during the boot animation. You knew that, right?

9. Use your phone normally while you calibrate the battery

10. Let it fill it up to 100% + 15 minutes or so. When it is truly finished charging, the battery should be cool.

11. If the phone is running hot, weird things can happen. For example, you may get no signal when you put the battery back in or the battery doesn't begin charging (the status bar battery icon doesn't change). Just let the phone cool off and it should work next time.

100% full is approximately 4200mV
As you can see in the cap below, it's showing only 60% at 4241mV (This was after booting up without the battery and putting the battery in)
A few minutes later, still plugged in, it showed 100% at 4225mV and then it went up to 4230mV.

Finally, I then unplugged the phone and I got a reading of 4196mV

Now, when I charge it up, it will go up to 4230mV everytime. I leave it plugged in an extra few minutes after that.
I highly recommend Battery Monitor Widget
Batterystats.bin gets recreated if you unplug your phone and plug it in again. So don't do that. Let it get recreated on the M logo (Step 6).
Thanks to pcphobic for a couple of important tips and to pcphobic and sileshn both for confirming that my phone isn't possessed!
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3rd March 2011, 02:00 PM |#11  
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Azhad (one of the two Androidiani OR developers) said another way to wipe battery

now i don't know what's the right one? delete batterystats.bin or battd folder's contents? with full or empty battery?
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calibrate battery, no battery boot, placebo, snake oil - fake

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