Database Users

The REAL low-down on "bat stats" and battery calibration

Apologies first -- I don't have the answer to the title of the thread. Rather, I'm posting this thread to (hopefully) get to the bottom of this whole matter, because there is just way, way too much floating around about this in way too many threads.
So, this is a request to the smarties out there, devs, engineers, et. al., to explain the precise, actual meaning and mechanism of "bat stats" on the Epic (and perhaps Android in general?).
So please, if you don't know with certainty about something related to this, don't post what you've heard, speculate, (informed) guess, etc. Let's keep this discussion to unquestionably known facts.
Here's what I do know as fact: Wiping Bat Stats in CWM does nothing more than delete a file in the /system filesystem (I don't remember the file atm, but someone else will surely speak up and fill in that detail). That's it. Nothing more.
This file is recreated and data written to it on subsequent boot.
That's all I know.
What I'd like to know, to complete the picture, is what is in this file, what this data means, how it's used by the device in managing the battery. If anyone knows the specific, actual specs and mechanism/algorithm for this, please explain.
After that, we can figure out, once and for all, what "calibrating" the battery means, and how best to do it. Further, it may be then as simple as keeping a copy of one's batstat file on their SD card, and simply putting it back after any reflash, obviating the need to go through some painful "calibration" procedure.

http://en.wikipedia.org/wiki/Lithium_ion_battery
There's no reason to "calibrate" a lithium battery. End of story.

mrzood said:
http://en.wikipedia.org/wiki/Lithium_ion_battery
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Click to collapse
And that was helpful, and relevant, how?
This thread is not about LiION battery technology; it's about the Bat Stats functionality of the Epic 4G, the technical details of it, and how it applies to battery "calibration".
The underlying battery technology could be NiMH, and the questions would be the same.

What he linked is correct. You asked about battery stats and calibration. There is no need to, " Calibrate" a LION. However, I am interested in the battery stats. I use three different batteries with my phone and get different usages with each.
dwallersv said:
And that was helpful, and relevant, how?
This thread is not about LiION battery technology; it's about the Bat Stats functionality of the Epic 4G, the technical details of it, and how it applies to battery "calibration".
The underlying battery technology could be NiMH, and the questions would be the same.
Click to expand...
Click to collapse

So calibration is a placebo? Apple suggests it just to appease the idiots?

mrzood said:
http://en.wikipedia.org/wiki/Lithium_ion_battery
There's no reason to "calibrate" a lithium battery. End of story.
Click to expand...
Click to collapse
What this article mentions in one place is about "conditioning" the battery which is different. LiOn batteries should fully discharge and recharge with no "memory effect". In other words, you can run them half way down and recharge, or 99% of the way down and recharge and the battery should charge to the same total power.
However, what the original poster is talking about is the phone's battery "stats" - how it reads the battery to determine how much charge is left and reports "25% remaining" or whatever. That can absolutely be changed, because I have seen it get screwed up. For example, I flashed a ROM this fall (don't remember which at this point, and it probably does not matter) and I seemed to be getting amazing battery life. In the first 6 hours of having the phone on, it dropped only 25%, which was great for me. However, I went into a movie and when I came out about 2 hours later the phone was dead. The first 25% took 6 hours and the last 75% took approx 2 hours. THAT was a problem with the battery stats being screwed up.
However, exactly how that is determined is something I do not understand either...

You're actually calibrating the rom's battery stats and to the people splitting hairs about the term "calibrating battery" get over yourselves.

What I understand about this is you have a variable amount of amperage this is one value at full and another at empty (or as empty as android gets). It tracks this against runtine and I think a couple of other variables to determine overall capacity. Each Phone and battery are slightly different. So it is a file that tracks this and is used to determine % or capacity. The recalibration is usually done best by getting a full charge and wipeing battery stats then running it dead to set your full and empty points.
Not super technical but a decent quick answer I hope.
Sent from my DROIDX using XDA App

Wiping battery stats doesn't improve battery life, says Google engineer

As posted on Android Central, a Google engineer has explained exactly what the batterystats.bin file contains:
"This file is used to maintain, across reboots, low-level data about the kinds of operations the device and your apps are doing between battery changes. That is, it is solely used to compute the blame for battery usage shown in the "Battery Use" UI in settings.
That is, it has deeply significant things like "app X held a wake lock for 2 minutes" and "the screen was on at 60% brightness for 10 minutes."
It has no impact on the current battery level shown to you.
It has no impact on your battery life.
Deleting it is not going to do anything to make your more device more fantastic and wonderful... well, unless you have some deep hatred for seeing anything shown in the battery usage UI. And anyway, it is reset every time you unplug from power with a relatively full charge (thus why the battery usage UI data resets at that point), so this would be a much easier way to make it go away."
https://plus.google.com/u/0/1050519...dVxPT#105051985738280261832/posts/FV3LVtdVxPT
http://www.androidcentral.com/wiping-battery-stats-doesnt-improve-battery-life-says-google-engineer

So whats the function for?
For us to imagine that i makes a difference?

This is just yet another Internet myth perpetuated by people, allowed to spread on forums and blogs.
It's been known for some time that the battery calibration is done by the power management chip, and the file plays no part.

DaddyCool08 said:
So whats the function for?
For us to imagine that i makes a difference?
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Click to collapse
The option is not from Google. CWM Recovery got it wrong it seems.
Sent from my GT-I9100 using xda premium

tietherope said:
The option is not from Google. CWM Recovery got it wrong it seems.
Sent from my GT-I9100 using xda premium
Click to expand...
Click to collapse
Of course i know that its not from G.
Maybe cwm team should take the option away then.

Diannes great to follow on G+. Shes after putting up some really good posts clearing up a few things

On some HTC devices, I believe battery stats are used to load heuristics into the fuel gauge chipset - but not on any Samsungs I am aware of. The fuel gauge on almost all Samsung devices is designed to not require calibration. (It is slightly less accurate and can get "faked out" in some corner cases, such as a reboot on low battery, for this reason - but it will also never go COMPLETELY wacky and will always converge towards truth.)
On some HTC devices, an improperly calibrated battery could cause a false low battery reading that would trigger an early shutdown - the battery wasn't really low but the device thought it was.
Note that the actual battery heuristics file on such devices might be something other than batterystats.bin - As I understand it, CM7 on the Nook Color had battery calibration issues for a while because it had a fuel gauge that DID require battery history info and the info was not being saved correctly.
However, I will say this again: Battery history is not, and cannot, be used in any way to affect the fuel gauge IC used in every Samsung device I have ever worked with.
http://www.maxim-ic.com/datasheet/index.mvp/id/6621 - Good read, that's the fuel gauge used by all first-gen Galaxy S phones. The MAX17042 used in the GSII is not publically documented, but it is similar - it has a few extra features which are not used in our device.

Wipe battery stats has always meant just that to me but many users interpret wiping stats as calibrating a battery .
So over time and from SGS1 days its been misused as wipe battery stats to recalibrate your phones battery .
I still wipe battery stats when i want to reset the readings .
jje

Deleting batterystats.bin just making a display of battery level correct.

I always knew it wont make a difference. Even when people RELIGIOUSLY "RECALIBRATE" the battery, its nothing more than killing the battery prematurely by such UNNECESSARILY DEEP DISCHARGE and CHARGE cycles! Max it can do is to reset the battery meter to hopefully display more accurate info temporarily.

Sergio_O said:
Deleting batterystats.bin just making a display of battery level correct.
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Click to collapse
No.
"It has no impact on the current battery level shown to you." from the OP

Wiping battery stats = Nothing.
Cycling battery = Win.

Wiping battery stats = Nothing
Wiping cache & dalvik cache = win win!

What is the proper way to calibrate the battery then?

Fwuffy86 said:
What is the proper way to calibrate the battery then?
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Click to collapse
Very simple you wipe battery stats if you have problems with the readings and even after flashing a new rom .
Battery calibration you put the battery in the phone and charge it you then use the phone .
This post tells you the battery calibrates itself .
jje

Sergio_O said:
Deleting batterystats.bin just making a display of battery level correct.
Click to expand...
Click to collapse
NO. The post linked to the OP is specifically saying that this is not the case.

Fwuffy86 said:
What is the proper way to calibrate the battery then?
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Click to collapse
Do nothing and wait - On Samsungs, rebooting the device on low battery (<50% or so) can cause it to falsely report low - it will converge towards truth (with the SoC estimate actually increasing over time) over the course of a few hours.

It definitely made a huge difference on my HTC Magic years ago, this was no placebo effect, however, I've never reset battery stats on either the SGS or S2 so can't comment.

tietherope said:
As posted on Android Central, a Google engineer has explained exactly what the batterystats.bin file contains:
"This file is used to maintain, across reboots, low-level data about the kinds of operations the device and your apps are doing between battery changes. That is, it is solely used to compute the blame for battery usage shown in the "Battery Use" UI in settings.
That is, it has deeply significant things like "app X held a wake lock for 2 minutes" and "the screen was on at 60% brightness for 10 minutes."
It has no impact on the current battery level shown to you.
It has no impact on your battery life.
Deleting it is not going to do anything to make your more device more fantastic and wonderful... well, unless you have some deep hatred for seeing anything shown in the battery usage UI. And anyway, it is reset every time you unplug from power with a relatively full charge (thus why the battery usage UI data resets at that point), so this would be a much easier way to make it go away."
Click to expand...
Click to collapse
maybe , but all the time that i wiped my battery it had positive effect on my battery drain !!!!!

Battery Calibration?

I am kind of amazed with what I am seeing, and am wondering if someone on XDA can help me understand this. So I was running CM7.x on my MT4G for over an year, and this past weekend I switched to CoreDroid because I wanted to try out Sense.
I had a bad feeling about the battery usage because the ROM was "heavier" than CM7.x in terms of UI, Graphics (of course because of Sense 3.5). I went ahead and installed the ROM anyways.
Within a couple of hours, I went from being fully charged to 5% battery....it was draining faster than anything I have seen before. I read CoreDroid release notes and they had mentioned about this severely fast battery drain.
Based on their recommendation, I fully charged the phone once battery level reached 5%. This time, my battery lasted about 17-18 hours, and again I fully charged it when it reached 5%.
Now after the second recharge, its been about 24 hours and I am at 97% battery. I didn't believe CoreDroid release notes that battery life will become better after couple of recharges; I thought it was a bunch of bull to get people to install their ROM.
I am glad to say I was wrong Can someone please explain this battery calibration deal to me?

Oh boy... This is a highly controversial topic. Here we go.
Basically there are people who swear by it and people who say it does nothing. That its all in your head.
Even this lady at google who helped create Android says it does nothing.
https://plus.google.com/105051985738280261832/posts/FV3LVtdVxPT
Sent from my HTC Glacier using XDA App

estallings15 said:
Oh boy... This is a highly controversial topic. Here we go.
Basically there are people who swear by it and people who say it does nothing. That its all in your head.
Even this lady at google who helped create Android says it does nothing.
https://plus.google.com/105051985738280261832/posts/FV3LVtdVxPT
Sent from my HTC Glacier using XDA App
Click to expand...
Click to collapse
Best link ever; most informative.
- I think everyone loves Dianne now.
- Someone has a flying car already ...
- In the middle of the most intellectual and technical discussion of battery usage that I have seen, someone asks what is the best facebook app - brilliant!
So...
1. Battery stats are calculated differently per phone and OS version.
2. Battery stats reporting is definitely not %100 accurate.
3. Battery percentage is calculated differently per phone and OS version.
4. Battery percentage reporting is definitely not %100 accurate.
5. On some phones, you can override battery charging limitations by 'bumping'.
6. 'Bumping' is not recommended as can shorten your battery life.
They actually did not cover the OP situation where you let that battery go below 5%, although I am always guilty of skim reading. Still, extremely informative and explains a lot of previously posted battery phenomena.

estallings15 said:
Oh boy... This is a highly controversial topic. Here we go.
Basically there are people who swear by it and people who say it does nothing. That its all in your head.
Even this lady at google who helped create Android says it does nothing.
Sent from my HTC Glacier using XDA App
Click to expand...
Click to collapse
Wow, that made up for intense reading - thanks a lot.
It can't be something in my head for sure, If the difference was say a couple of hours I probably would have agreed with "the lady at Google" But I went from 2-3 hours to 24+ hours, so yes it's not in my head
Thanks again for your feedback.

Homerbsharp said:
Best link ever; most informative.
- I think everyone loves Dianne now.
- Someone has a flying car already ...
- In the middle of the most intellectual and technical discussion of battery usage that I have seen, someone asks what is the best facebook app - brilliant!
So...
1. Battery stats are calculated differently per phone and OS version.
2. Battery stats reporting is definitely not %100 accurate.
3. Battery percentage is calculated differently per phone and OS version.
4. Battery percentage reporting is definitely not %100 accurate.
5. On some phones, you can override battery charging limitations by 'bumping'.
6. 'Bumping' is not recommended as can shorten your battery life.
They actually did not cover the OP situation where you let that battery go below 5%, although I am always guilty of skim reading. Still, extremely informative and explains a lot of previously posted battery phenomena.
Click to expand...
Click to collapse
Lol....yea that FB app question was pretty brilliant I'll try to get in touch with CoreDroid folks, and see if they can answer my question.
I mean it does work, it's almost like a miracle to me.

I know. I just can't figure out WHY. Its been really bothering me.
Sent from my HTC Glacier using XDA App

Jessooca said:
Which battery calibration app are you using?
Sent from my HTC Glacier using xda premium
Click to expand...
Click to collapse
None, I am just surprised to see improved battery life after couple of 'full-drain, full-charge" operations.
BTW, care to suggest a good battery calibration app? Much appreciated.

well, the best battery calibration app Ive used is Battery Calibration by NeMa, but now after reading this thread it seems that they dont really do anything

ajrulez said:
None, I am just surprised to see improved battery life after couple of 'full-drain, full-charge" operations.
BTW, care to suggest a good battery calibration app? Much appreciated.
Click to expand...
Click to collapse
The drain-charge cycles is just a way to calibrate the battery- takes more time to "forget" the old stats, so people either use an app or manually delete the battery statistics so one can start accumulating fresh statistics.
After a few days you get your statistics right, from then on the battery indicator will be more or less accurate.
Battery drainage has nothing to do, really, with how many times you'll calibrate or drain/ charge or whatever. It has to do with how much you use screen on, Wifi, BT, gps, partial wakelocks, apps syncing etc. In other words- use your phone and be assured battery is going to drain. Leave it alone, let it sleep- battery will last a couple of days...
Sent from my HTC Glacier using Xparent Cyan Tapatalk

just to clarify, and sorry for butting in, but there is no such thing as "calibrating your battery"... this has been debunked by many people who understand android's Linux kernel and even an android engineer at Google.
the batterystats.bin file is simply that, a bin. it does nothing more than collect dumped statistics of what exactly has been using your battery, how long, how much power those processes used, etc. it has absolutely nothing to do with your phone's ability to display correct information about how much juice you have left - that function is within the Linux kernel which monitors, and controls power throughout the device.
ask yourself this... ever flashed a ROM with say 50% power left on a charge? what happens after your first boot? does your phone suddenly have no idea how much charge is left? no. it doesn't. because the new kernel you just flashed with your ROM is picking up right where you left off.
wiping battery stats is useless. period. it.does absolutely nothing to better battery life. that is fact. that is your phone. that is your Linux platform and straight truth in how it works.
and since it is stored in the data directory, every time you flash a ROM and wipe data, you are wiping the battery stats... so why do you boot up and do it again... I know... good question.
Sent from EVO 3D using XDA premium

aznprodgy said:
well, the best battery calibration app Ive used is , but now after reading this thread it seems that they dont really do anything
Click to expand...
Click to collapse
Hehe, yes I doubt if these battery calibration do anything.
estallings15 posted a very informative link in 2nd or 3rd post (of this thread)....all these battery calibration apps simply delete the battery stats file at least thats what one from NeMA does anyways

cobraboy85 said:
just to clarify, and sorry for butting in, but there is no such thing as "calibrating your battery"... this has been debunked by many people who understand android's Linux kernel and even an android engineer at Google.
the batterystats.bin file is simply that, a bin. it does nothing more than collect dumped statistics of what exactly has been using your battery, how long, how much power those processes used, etc. it has absolutely nothing to do with your phone's ability to display correct information about how much juice you have left - that function is within the Linux kernel which monitors, and controls power throughout the device.
ask yourself this... ever flashed a ROM with say 50% power left on a charge? what happens after your first boot? does your phone suddenly have no idea how much charge is left? no. it doesn't. because the new kernel you just flashed with your ROM is picking up right where you left off.
wiping battery stats is useless. period. it.does absolutely nothing to better battery life. that is fact. that is your phone. that is your Linux platform and straight truth in how it works.
and since it is stored in the data directory, every time you flash a ROM and wipe data, you are wiping the battery stats... so why do you boot up and do it again... I know... good question.
Sent from EVO 3D using XDA premium
Click to expand...
Click to collapse
Yep, agree with your comments 100%. After reading the link posted by estallings15 earlier in this thread, the myth of battery calibration was busted

I agree with most that Battery Calibration is a joke, and doesn't mean anything. However, batteries in many devices (not just our Cell Phones) seem to benefit from proper discharge/full charge cycles. In fact, it's usually recommended in things like electric RC cars that you completely run down the battery as far as you can go (realistically of course!) prior to charging; also to prolong battery life. I always notice at least slightly longer use times if I don't always pop the thing on a charger at 75%. But go with what works for ya, and of course some roms DO drain faster than others. And less screen haha

[Q] Battery recalibration

I have been heavily using my N7, unplugged, for the past 3 hours and the battery status is still at 100%. I have rebooted 3x to see if the battery status system would reset, but to no avail.
Earlier today my N7 gave me the 14% low charge warning and then jumped to 0% and triggered automatic shutdown during the 30 second walk to get to the charger.
SpareParts is currently showing my battery voltage as 3 mV ... which certainly can't be correct.
It seems to me that my battery is in need of recalibration. I tried searching the issue, but the signal-to-noise is really low due to the previous fad of deleting batterystats.bin (despite it having zero effect).
Is there any way to force an actual recalibration? I also recognize it is within the realm of possibility that my device has a hardware failure; however, I thought I would check for simple remedies first.
Thanks.

If you have root access go onto the Google play store and look up battery calibration...it is the first app
Sent from my Nexus 7 using XDA Premium HD app

Thanks for your reply.
That app is the Android equivalent of a placebo. If you check the store, the description clearly states, "This program does it by removing the batterystats.bin system file."
Unfortunately, that file has nothing to do with battery calibration. That also means that the CWM "wipe battery stats" function does nothing for calibration either.

Da faq then how do u calibrate the battery?
Sent from my Nexus 7 using XDA Premium HD app

Right, this goes back to the low signal to noise ratio. Every FAQ about battery calibration that I have found discusses removing batterystats.bin (either manually or with an app).
As I said before, that has nothing to do with battery calibration.
Therefore, I decided to ask here to see if anyone knows how to *actually* recalibrate the battery.

I had the same issue. Battery stuck at the critial battery " ! " sign the day after I rooted (just FYI, using wugfresh toolkit), and before flashing anything new. So that was pretty weird. I thought it was some kind of hardware failure too, and was about to prise open the back to check the battery. Because even charging didn't help. It said "charging", but was stuck at 0% for ages. I gave it one last shot and this is what I did -
1) used an app to remove the batterystats.bin file (It probably didn't calibrate the battery like you said. Maybe it doesn't improve performance, and this step may be completely useless, but I'm just laying it out how I did it)
2) I turned off the device and charged it from the PC (someone who had a similar issue said he tried this and it worked for him. I don't know if there's any technical basis to it - but I'm no dev and so I thought I'd give it a shot)
3) It charged on the PC for a few hours (device was off throughout). Finally I disconnected and restarted, and it was fine again. Fully charged, and draining as normal.
So that's how it worked for me. Now the funny thing is I flashed a new ROM today (codefirex SR6), and soon after I rebooted I got the same critical battery " ! " warning. And just as I was thinking "oh no, not again" it switched back to 91% which was where I was before flashing the new ROM. I played around with it for a bit, then went back to recovery to flash another kernel. On reboot - back to critical battery warning. This time it didnt switch back to 90% even after a few minutes.
So I am now repeating the 3 steps above and seeing if it works.
Also, after all this, I feel on my device atleast, it so far doesnt lool like a hardware fault (because I fixed it the first time without having to touch the battery or its connections, because I saw the icon change from " ! " to the normal state of 90% battery the first time I flashed codefirex)
It looks like a software bug. But that's just me speculating.The technical aspects are beyond me, and I am going purely by what I saw.
I'll be watching this space carefully!! I really want to know how others have fixed this problem, and/or if it's a widespread issue.
Cheers
Update: So I switched it back on after about 20 minutes - and no change. Still showing battery at charging, 0%
Another interesting thing - I BetterBatteryStats is not reading anything. I set a custome reference to see what's happening, but it shows 0 seconds, no stats etc etc.. even after I refreshed and tried. So it's not able to read whatever it reads to generate those stats.
I've powered down again, and am leaving it to charge for longer. Maybe a couple of hours. So that my 90% battery should definitelt be fully charged by then.
At the moment I don't want to create a new post for this issue, so I'll update with my findings later.

This tirade isn't directed at anyone on this thread, I'm just generally dismayed that this snake oil still perpetuates despite clear and convincing verification that it does nothing...
I can't believe that people still believe in the snake oil that these apps peddle. Battery calibration apps are 100% worthless. You cannot calibrate your battery by manipulating batterystats.bin, and any dev that tells you otherwise is simply ignorant of how Android operates. The file contains no information whatsoever pertaining to battery charge indication. You'd achieve the same results by rubbing a baked potato over your device as you would using a calibration app.
This myth was debunked officially a full year ago by Google's Android team. .
The one and only way an end user can ‘”calibrate” the battery's internal fuel gauge would be to FPO a full charge/discharge cycle on the battery. This should not be done frequently, as it negatively affects the longevity of the battery, though.
Sent from my Nexus 7 using Tapatalk HD

Your rant is extraneous, which you would have understood had you read the thread. If you happened to have read the thread and decided to rant regardless, then I'm perplexed why you believed that your rant would contribute to the discussion.

najaboy said:
This tirade isn't directed at anyone on this thread, I'm just generally dismayed that this snake oil still perpetuates despite clear and convincing verification that it does nothing...
I can't believe that people still believe in the snake oil that these apps peddle. Battery calibration apps are 100% worthless. You cannot calibrate your battery by manipulating batterystats.bin, and any dev that tells you otherwise is simply ignorant of how Android operates. The file contains no information whatsoever pertaining to battery charge indication. You'd achieve the same results by rubbing a baked potato over your device as you would using a calibration app.
This myth was debunked officially a full year ago by Google's Android team. .
The one and only way an end user can ‘”calibrate” the battery's internal fuel gauge would be to FPO a full charge/discharge cycle on the battery. This should not be done frequently, as it negatively affects the longevity of the battery, though.
Sent from my Nexus 7 using Tapatalk HD
Click to expand...
Click to collapse
Dang dude take your Xanax. But you are right that a full charge cycle is all the calibration that ever needs to be done. But the value of that to somehow correct the display is doubtful. On some devices it might be helpful, but the fuel gauge capabilities on android are pretty basic from what I have read.
Sent from my N7 using XDA Premium
Dirty AOKP 3.2 & m-kernel+ a33

ezas said:
But you are right that a full charge cycle is all the calibration that ever needs to be done.
Click to expand...
Click to collapse
I did that twice this weekend. Just now, my N7 jumped from 20% to 0% and shut itself down again. As a bonus, because it's now dying directly from ~20% I don't even get a low charge warning at all. I think I will explore the warranty replacement route for my device.
Too bad, because it's just a battery calibration issue.

Try rebooting into recovery, go to advanced menu and wipe battery stats, then reboot.
EDIT: NVM, I think we established wiping battery stats isn't re-calibrating.

Southrice said:
Try rebooting into recovery, go to advanced menu and wipe battery stats, then reboot.
EDIT: NVM, I think we established wiping battery stats isn't re-calibrating.
Click to expand...
Click to collapse
Haha, thanks anyway. It's amazing how this concept circulated in the online echo chamber and became "well established knowledge"... yet turned out to be nothing but a myth.
Between my searches and all the responses so far, I'm left to conclude there is no way to recalibrate the battery. Not even doing a full charge/discharge cycle helps (besides, if it's so automatic and behind the scenes, how would one even tell?)

How to Optimize battery drain?

Hello,
I use Tytung's ICS 4.0.4 for my T-Mobile HTC HD2 (NAND), I've been using this ROM for months.
As such there is no problem with functioning of the ROM.
But my battery drains at a very fast rate. With 6hrs of use it drains to 20% at lowest brightness and no major applications running (2 applications in background at most).
Data enabled (2G).
What to do? Please help!!
Sent from my T-Mobile HTC HD2 using XDA Premium.

Can you download CurrentWidget from the Play store and give a value in mA? If you mean 6hrs without any usage then that's pretty poor. Try turning on airplane mode to determine whether it's an app or one of your connections that's causing the problem.
In currentwidget, the values should be approximately 4mA drain in standby with any connections enabled and 2mA in standby in airplane mode. Screen on drain varies a lot more.

OK, thanks. will revert back soon.

With screen OFF, networks ON, 2g enabled....drain is 6mA.
With screen OFF, airplane mode ...drain is 5mA.
Sent from my T-Mobile HTC HD2 using XDA Premium.

That's high but shouldn't be causing a drain of 20% in 6 hours. It's probably just draining a lot when you're using the phone, and there's not much you can do other than turning the brightness down which you've done already.

try wiping battery stats through recovery...fully charge your battery then wipe stats and let your battery to get fully discharge before you connect it to a charger for about a week...My battery never lasted more than a half day before doing this...now it lasts more than a day...Hope this works

Okz.. will try this..hope this works.
Sent from my T-Mobile HTC HD2 using XDA Premium.

eliaskammas said:
try wiping battery stats through recovery...
Click to expand...
Click to collapse
I wonder if this myth will ever die..
Google engineer Dianne Hackberry has talked about several myths about the Android operating system, including wiping battery stats.
The reasoning behind that piece of advice was something like this: If you, at some point, did not charge your Android device fully (for example, only to 80%), it would supposedly remember that battery level as “fully charged” – in this case, you’d only ever get to use 80% of your battery, which is of course less than optimal. So, if you wipe the battery stats, usually done in ClockWord Mod Recovery, the device would “forget” the previous level, here 80%, and instead charge to the full 100% once again, thereby re-calibrating the battery. Or, as Hackborn puts it in more technical terms:
The battery indicator in the status/notification bar is a reflection of the batterystats.bin file in the data/system/ directory.
However, as she explains, that’s not the case. Because those battery stats, stored in the batterystats.bin file, are only used to maintain information about what is using the battery when not recharging. That is, it essentially holds the information displayed in the Settings > Battery screen. Nothing more, nothing less. Thus:
It has no impact on the current battery level shown to you.
It has no impact on your battery life.
What’s more, you’ve probably noticed that the battery usage data is reset once you recharge your device anyway. From this you can correctly deduce that the battery stats are wiped as well – every time your device is recharged. More or less every day. If there was any effect, you would’ve noticed it without going into recovery and doing that stuff. Typical placebo, eh?
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I’m as confused as a baby in a topless bar...

^Whenever someone asks 'how do I reduce my battery drain', ten people immediately jump in with 'CALIBRATE!!11oneeleven!'. No hate directed at whoever posted that advice here, I understand how easy it is to be misinformed (as I was about using SetCPU ), I just think that rumours like this are too easily presented as facts.

NYLimited said:
I wonder if this myth will ever die..
Google engineer Dianne Hackberry has talked about several myths about the Android operating system, including wiping battery stats.
The reasoning behind that piece of advice was something like this: If you, at some point, did not charge your Android device fully (for example, only to 80%), it would supposedly remember that battery level as “fully charged” – in this case, you’d only ever get to use 80% of your battery, which is of course less than optimal. So, if you wipe the battery stats, usually done in ClockWord Mod Recovery, the device would “forget” the previous level, here 80%, and instead charge to the full 100% once again, thereby re-calibrating the battery. Or, as Hackborn puts it in more technical terms:
The battery indicator in the status/notification bar is a reflection of the batterystats.bin file in the data/system/ directory.
However, as she explains, that’s not the case. Because those battery stats, stored in the batterystats.bin file, are only used to maintain information about what is using the battery when not recharging. That is, it essentially holds the information displayed in the Settings > Battery screen. Nothing more, nothing less. Thus:
It has no impact on the current battery level shown to you.
It has no impact on your battery life.
What’s more, you’ve probably noticed that the battery usage data is reset once you recharge your device anyway. From this you can correctly deduce that the battery stats are wiped as well – every time your device is recharged. More or less every day. If there was any effect, you would’ve noticed it without going into recovery and doing that stuff. Typical placebo, eh?
---
I’m as confused as a baby in a topless bar...
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Click to collapse
LOL i was just gonna post but ya beat me to it
i will just add the link to the xda news post about it
http://www.xda-developers.com/andro...-battery-stats-does-not-improve-battery-life/

Nigeldg said:
^Whenever someone asks 'how do I reduce my battery drain', ten people immediately jump in with 'CALIBRATE!!11oneeleven!'. No hate directed at whoever posted that advice here, I understand how easy it is to be misinformed (as I was about using SetCPU ), I just think that rumours like this are too easily presented as facts.
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Click to collapse
And I shall not tell you how many times I did erase that bloody file before I too learned the truth. :crying:
Kameirus said:
LOL i was just gonna post but ya beat me to it
i will just add the link to the xda news post about it
http://www.xda-developers.com/andro...-battery-stats-does-not-improve-battery-life/
Click to expand...
Click to collapse
Want me to go back and erase it for ya? No biggie...

Lol...
When one doesn't know a thing, he can be easily fooled about it.
Anyways ...Learnt something new today... :thumbup:
Thank you everyone.
Sent from my T-Mobile HTC HD2 using XDA Premium.

NYLimited said:
Want me to go back and erase it for ya? No biggie...
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Click to collapse
LMAO no

sonalikagaur said:
When one doesn't know a thing, he can be easily fooled about it.
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Click to collapse
As I said to Nigeldg in an earlier post:
NYLimited said:
And I shall not tell you how many times I did erase that bloody file before I too learned the truth. :crying:
Click to expand...
Click to collapse
sonalikagaur said:
Anyways ...Learnt something new today... :thumbup:
Click to expand...
Click to collapse
And that is all that's important.

to sonalikagaur....
obviously as the guys say don't bother trying my advice
to everyone...
at least now I know not to tell anyone about battery stats again...but now there is a wonder in my head...what made my battery last longer than it did before? I wasn't kidding that it lasts half a day longer than before...obviously battery stats didn't make the job...what did.? :-/

eliaskammas said:
to sonalikagaur....
obviously as the guys say don't bother trying my advice
to everyone...
at least now I know not to tell anyone about battery stats again...but now there is a wonder in my head...what made my battery last longer than it did before? I wasn't kidding that it lasts half a day longer than before...obviously battery stats didn't make the job...what did.? :-/
Click to expand...
Click to collapse
I found out something.... usually I used to keep my 2G ON the whole day...but when I switched my data OFF when not in use...my 6hrs...20% battery remaining changed to 8hrs..n 75% remaining.
That's a huge difference.
Can anyone suggest a good app for this? Switching my data OFF automatically when not in use .!!
Sent from my T-Mobile HTC HD2 using XDA Premium.

I think Juice Defender has this functionality built in.

sonalikagaur said:
I found out something.... usually I used to keep my 2G ON the whole day...but when I switched my data OFF when not in use...my 6hrs...20% battery remaining changed to 8hrs..n 75% remaining.
That's a huge difference.
Can anyone suggest a good app for this? Switching my data OFF automatically when not in use .!!
Click to expand...
Click to collapse
I would guess that many so called "battery saver" apps might have it, not really sure.
I don't turn off data when not in use automatically but I do use Tasker to turn it off for several hours while I sleep.

NYLimited said:
I would guess that many so called "battery saver" apps might have it, not really sure.
I don't turn off data when not in use automatically but I do use Tasker to turn it off for several hours while I sleep.
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Click to collapse
Yeah Tasker can do this but it's a paid app. Juice Defender is free and can also do the same thing in this case. I agree that Tasker is awesome but not necessarily for saving battery, more for ease of use.

Nigeldg said:
^Whenever someone asks 'how do I reduce my battery drain', ten people immediately jump in with 'CALIBRATE!!11oneeleven!'. No hate directed at whoever posted that advice here, I understand how easy it is to be misinformed (as I was about using SetCPU ), I just think that rumours like this are too easily presented as facts.
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Click to collapse
Could your go into more detail about you're previous misinformation about SetCPU?
Sent from my ZeJstersHD2 using xda premium