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How does calibration works?

Why calibrate my battery?

The process of calibration helps maximize battery life by 'teaching' Android the maximum % and voltage range supported by the battery.

This will ensure the longest running time on battery and enhance the life of the battery.

How to to calibrate my battery?

The calibration process does not require any application! It's a matter of running full charge and discharge cycles. An app can definitely help though!

A full charge cycle starts at near 0% and ends at 100% when the battery is not charging anymore (usually one hour to one hour and a half after reaching 100%).

A full discharge cycle starts at 100% (best after a full charge cycle) and ends at 0% or more realistically when the phone shutdown by itself and it becomes impossible to start it without plugging it in.

WARNING: If you have any version of CWM recovery, please make sure it doesn't have the charge bug, that is the phone is not chargign while phone's completely off (not standby).

What can I gain from battery calibration?

Simply said, without calibration a device might shutdown at 3% or charge upto 99%. After running calibration a few times it will shutdown at 1 or 0% and charge up-to 100%. Tested on an Iconia A500 and a HTC Sensation!

How can Battery Monitor Widget help calibrate my battery?

The app can help set an alarm for an actual end of charge, and also measure the % and voltage ranges.

It will then measure the aging total battery capacity from a starting value (usually the device's specs).

How to use the Calibration screen?

You first need to run some full charge and discharge cycles. At least from 100% to 3%. It is best to run the cycles until the % and voltage ranges are maximized. This screen can be used to check range evolution over time.

Once the ranges are maximized, this can be used as initial real-life specifications (which may slightly differ from manufacturer's specs), except the actual battery capacity which usually follows specifications.

Over time, the calibration screen will provide information on battery aging and it's new total capacity.

Please refer to that page for more details.


An example?

Let's consider an example with a HTC Sensation device. A battery having a voltage from 3200 to 4200 with a capacity of 1520mAh. That's the manufacturer's specs but real-life shows it's different (for every phone).

On that phone I initially got a voltage ranging from 3353 upto 4206, capacity from 3% upto 100%.

After 3 full charge/discharge cycles ranges went to 3170-4212 and 1% upto 100%!

If in the future voltage ranges from only 3230 upto 4196 (as it happened with an old HD2 battery), then the actual capacity will be reduced accordingly.


I Have a Question about battery calibration. I also have a HTC Sensation, but I bought a better battery for my phone - mugen 1950 mAh (originally for EVO 3d). 

I have manually entered capacity. After few cycles calibration tool says:

measured: 4116mAh. Is it really possible? I don't want to destroy my battery (since it wasn't cheap). 

Or maybe it is just a mistake with transaltion or something (I am using polish test version - I am the transaltor)?  It fits mV rather than mAh. 

<p>pozdrawiam / best regards</p>
<p>Lukasz Podgorski</p>

That's odd, usually the calibration screen provides accurate results on a Sensation.

Could happen if you use an old version of the app. Though I suppose you're running the test version I sent, so it should be fine... Kinda odd.

You can first check the mA retrieval method, but it should be ok (HTC Sensation or HTC Evo 3D depending on custom ROM).

Note also the app is only monitoring: no risk to destroy your battery.

The measured mAh is informative and can help calculate remaining time based on battery drain eg how long will it last with current usage.

Can you send your history file, I'll run it locally to see what comes up.


I am also having the same problem. I tried calibrate on my original battery (1650mAH) after few cycle of discharge and recharge. The calibrated result is 1930mAH. I have another 3rd party of 2650mAH and after few cycle of discharge and recharge, the result is 5858mAH. Please advise...

I suppose you have a phone with estimated mA. No real mA reported. A Galaxy Nexus?

Also, make sure you run the latest version of the app, older version used the battery drain which is very inaccurate.

Next update should provide a little more accuracy for this type of phones. Testing on a SGS2 and GN.

EDIT: Also make sure the user-defined battery capacity is set properly. If wrongly set, wrong results will be drawn from it. So if you get higher measured mAh and constantly update the user-defined capacity, it will only raise over time.


Next update will display a warning before updating the capacity and also be a little more precise.


ATM, some users only update capacity when it's higher! Not lower, so they keep getting higher results!


I am using the Galaxy S2 with version 2.0. The results is much higher than the manufacturer spec.

I do have a SG2, set to update history every 10 minutes, and results are very close.

Did you update the mAh capacity used with the measured one? If so it will definitely make it worth, as mA is derived from the user-defined mAh!

Please re-enter the correct mAh manually in the monitoring settings, and wait for the next update. It should be more accurate. Due today or tomorrow.


I had mine to update the history on every 5 minutes. I will change to 10 minutes. The mAH I entered as per the manufacturer spec. (1650mAH and 2650mAH).

I just installed BMW Pro on my HTC Desire unrooted.

I recorded a full  ( from 0%to 100%) charge / discharge cycle. the update history is every minute.

After the first cycle  full cycle without any interupt I am quite surprised, I do not get any estimated capacity

I notice that the default setting is an history update evry 5 minutes . Is this paremter critical?

I have used for many months BMW ( free version) with a 1mn setting and I got estimated capacity!!!!!!

This will send the app settings and the history file used to calculate mAh. If you could also add a screen shot of the calibration screen that will help too.

Don't forget to add a quick note to the email generated referencing your question.

Sorry for the inconvenience.

Sorry,  I have wipped  both files. I have only kept a copy of the data file '' battery_history.txt'' on my PC.

I am running once again a full cycle with 5mn history update. I will let you know the results and if any problem I will send you a ''ma support request''

Thanks for your quick answer

I have finished the charging cycle and BMW measured a realistic capacity value with a 5mn history update. It seems that a 1mn history update is not  appropriate for capacity value measurement.

I continue testing BMW Pro

With a 1 minute logging rate, the app loads only 2 days of history. Hence if you have a 2 or 3 days run-time, the charge cycle doesn't get loaded, and the app cannot calculate capacity.

I suppose that's the problem you experienced. Though the app should show a special message about it beneath the buttons.

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