Google Engineer Debunks Myth : Wiping Battery Stats Does Not Improve Battery Life - Galaxy S II General

Got the information from here
www.xda-developers.com/android/goog...-battery-stats-does-not-improve-battery-life/
Google Engineer Debunks Myth : Wiping Battery
Stats Does Not Improve Battery Life
There you have it, in the title. Google engineer Dianne
Hackborn, who has previously explained Android’s hardware
acceleration , took to Google+ again to clarify some myths
about the Android operating system. This time, it’s a point of
common advice that you’ll see in virtually every FAQ thread
about custom ROMs and flashing: wiping battery stats in
order to improve battery life.
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 knew about that ^^
Sent from my GT-I9100 using xda premium

dorian95 said:
I knew about that ^^
Sent from my GT-I9100 using xda premium
Click to expand...
Click to collapse
Are we blindly following the myth then?

We already have this thread
http://forum.xda-developers.com/showthread.php?t=1444231
Closed.

Related

Quick Battery-Life Question (Experienced Users Please)

Hey everyone,
I'm kind of a noob when it comes to all things XDA (but I'm learning.) Anyways, I was wondering what kind of battery life you all get from the different ROMs you've flashed.
So far I've only flashed Nero, Bionix, and Flagship. I had pretty good battery life from Nero, but I was wondering what kind of battery life that you've experienced with other ROMs like Axura and Trigger (because with Bionix and Flagship, my battery life has been fugazi.)
Thanks in advance, y'all.
Sorry if this topic comes up often.
With axura my battery lasts 16 hours with possibly 600+ texts and youtube alot music about 1 hour a few phone calls alot of web.
I only need it to last 12 hours because I charge overnight so I'm good.
I reconditioned too btw
Does reconditioning actually improve battery life or does it simply make the battery indicator more accurate?
It makes it more accurate. Which in terms helps battery because it reads it perfect so ull last longer
Axura is widely considered to have the best battery life. After flashing a new rom you should let your phone charge to 100% and then wipe battery stats in CWM recovery. It can take several days for reading to be taken from the battery so your battery life will usually improve over time.
Hey, I just wanted to thank you all for your input. I decided to go with the latest version of Axura, and so far I've been loving it. I'm not even a day in and I've noticed a difference.
Thanks once again.
+1 On Axura best battery life........
soltheman said:
Hey everyone,
I'm kind of a noob when it comes to all things XDA (but I'm learning.) Anyways, I was wondering what kind of battery life you all get from the different ROMs you've flashed.
So far I've only flashed Nero, Bionix, and Flagship. I had pretty good battery life from Nero, but I was wondering what kind of battery life that you've experienced with other ROMs like Axura and Trigger (because with Bionix and Flagship, my battery life has been fugazi.)
Thanks in advance, y'all.
Sorry if this topic comes up often.
Click to expand...
Click to collapse
first thing to do is
Charge Until 100%
choose rom
Run The Phone All Day, Let It Die
Charge Until 100%
Reboot Into Recovery
Select Reinstall Packages (Do it again if needed)
Select Advanced
Select Wipe Battery Stats
Laazyboy said:
Does reconditioning actually improve battery life or does it simply make the battery indicator more accurate?
Click to expand...
Click to collapse
Neither. "Conditioning" skews the discharge curve from which the battery indicator indexes it percentages. As a result, the battery appears to discharge at slower rate ("better battery life") over the first two-thirds or so of the discharge cycle and then craters like a lead balloon at the end of the discharge cycle. (You really need to have a battery indicator that shows discharge in 1% increments, such as "blue segmented battery mod" to see this.)
To understand this requires a light understanding of the so-called "battery stat tables." There is an entry in the battery stat tables for each percentage of remaining battery charge, in increments of 1%. So, the table contains entries 100%, 99%,... down to 1%. Associated with each percent of remaining charge entry in the table is a battery terminal voltage and a timestamp. Unfortunately, the smart phone cannot measure actual remaining battery charge. All the system knows is a series of battery terminal voltage measurement taken at even periodic intervals. The algorithm builds the battery stat table to relate each measured voltage to a corresponding “percentage of remaining charge” entry in the table. In normal operation, the system accumulates these measurements over several charge/discharge cycles and analyzes the rates of changes of voltages to refine the discharge curve. After several charge/discharge cycles the percentages, which are displayed on the screen as a battery indicator, become more refined and accurate.
At some point someone apparently thought that it would be a good idea to attempt to manipulate the process of building the battery stat tables. This resulted in the so-called "conditioning procedure." The conditioning procedure consists of fully charging the battery, then deleting the battery stats, and then draining the battery quickly and completely using heavy loads, perhaps in 1 to 2 hours.
What this accomplishes is that the battery stat mechanism builds a new, steep discharge curve based upon the rapid discharge operation. This crude, initial discharge curve has "learned" that the battery should discharge quickly, because it did so during its "training” discharge. More specifically, each "percentage discharge" entry for the first 1/2 to 2/3 of the discharge curve (corresponding to the first 50-75 table entries) will be associated with an abnormally lower voltage (due to the faster rate of decrease in voltage during the "training" discharge cycle) than would be the case if the table had been built normally, over time.
Now, let us think about what happens during the subsequent discharge cycle. We charge the battery to full. Now we begin to use the phone normally, discharging the unit over a period of 12-18 hours, for example. Now the phone experiences a slower rate of change of battery voltage over time, because the load is much lower than that of the forced "training" discharge. Now the algorithm measures a voltage and then attempts to map that voltage to a corresponding percentage discharge table entry. The result is that the battery indicator on the phone shows a very low rate of discharge over many hours. This leads people to erroneously conclude that the "battery conditioning" procedure results in improved battery life. However, this is merely an illusion. The battery indicator is, at this point, simply displaying an incorrect number for the remaining battery life. As a consequence, the battery indicator must "catch up with reality" later in the discharge cycle. This is manifested toward the end of the discharge cycle as the battery indicator drops precipitously from perhaps 35% to zero in a very small amount of time. In any case, fortunately, the weirdness done by "battery conditioning" goes away within a few days as the battery stat algorithm tunes the discharge curve each discharge cycle to bring it ever further in line with the actual average usage of the phone owner. It is a myth that the battery stats become inaccurate over time. To the contrary, the algorithm continuously tunes the tables based upon usage patterns so that the battery indicator becomes more and more accurate.
I do not know where this practice originated, but I do have a cynical hypothesis. The ROM cookers typically mix-and-match code elements from different software releases and otherwise change up the timing, sequencing, etc. of various processes. Doing so may have battery life consequences, because the resulting mish-mash of components may hinder or prevent sleep mode operation, cause processes to run for more time than they should, etc. You can see how "battery conditioning" could mask an acute battery performance problem during the first few hours after a person has flashed a ROM and is watching performance characteristics especially closely. ‘Nuf said on this subject.
Sample battery discharge chart and accompanying notes attached below.
soltheman said:
Hey everyone,
I'm kind of a noob when it comes to all things XDA (but I'm learning.) Anyways, I was wondering what kind of battery life you all get from the different ROMs you've flashed.
So far I've only flashed Nero, Bionix, and Flagship. I had pretty good battery life from Nero, but I was wondering what kind of battery life that you've experienced with other ROMs like Axura and Trigger (because with Bionix and Flagship, my battery life has been fugazi.)
Thanks in advance, y'all.
Sorry if this topic comes up often.
Click to expand...
Click to collapse
Tutorial for tuning system to increase battery life here:
http://forum.xda-developers.com/showthread.php?t=823025&page=4
xriderx66 said:
With axura my battery lasts 16 hours with possibly 600+ texts and youtube alot music about 1 hour a few phone calls alot of web.
I only need it to last 12 hours because I charge overnight so I'm good.
I reconditioned too btw
Click to expand...
Click to collapse
600 texts in 16 hours is nearly 38 texts an hour, 4,200 texts a week, 18,000 texts every month. WTFBBQ?

"Android System" draining battery

installed EF02... I pull it off the charge around 6:30am...by 11am with casual texting...its down to 20%.. without doing any except moving around screens...it's 8:30am and my battery is at 72%..something is not right...
settings -> about phone -> battery use
shows that my andriod system is at 80%
anyone else have the same stats? hows your battery life?
jackal424 said:
installed EF02... I pull it off the charge around 6:30am...by 11am with casual texting...its down to 20%.. without doing any except moving around screens...it's 8:30am and my battery is at 72%..something is on right...
settings -> about phone -> battery use
shows that my andriod system is at 80%
anyone else have the same stats? hows your battery life?
Click to expand...
Click to collapse
did you calibrate? wipe battery stats?
android system is supposed to take power from the battery... that's what the battery is there for.
algorhythm said:
did you calibrate? wipe battery stats?
android system is supposed to take power from the battery... that's what the battery is there for.
Click to expand...
Click to collapse
its not a calibration issue...however I have done that before.
is your phone reading the same?
the android battery stats is reporting that android system's running apps are using 80% of the battery...
jackal424 said:
its not a calibration issue...however I have done that before.
is your phone reading the same?
the android battery stats is reporting that android system's running apps are using 80% of the battery...
Click to expand...
Click to collapse
44%, full bar.
It's a relative statistic. If your screen were on more than it would take up a larger percentage of the power used, "Android System" is just a general name for things that aren't individually covered (display, cell standby etc.) and if the screen is off and you don't have terrible service it makes sense for most of the power to be used by the OS itself.
063_XOBX said:
It's a relative statistic. If your screen were on more than it would take up a larger percentage of the power used, "Android System" is just a general name for things that aren't individually covered (display, cell standby etc.) and if the screen is off and you don't have terrible service it makes sense for most of the power to be used by the OS itself.
Click to expand...
Click to collapse
make sense, but my battery drain is just ridiculous...wasn't this bad on froyo..
jackal424 said:
make sense, but my battery drain is just ridiculous...wasn't this bad on froyo..
Click to expand...
Click to collapse
It's not an official release, don't expect it to be perfect. It's perfectly normal for bugs to come up in leaks.
yay a problem I don't have..
I pulled my phone off the charter at 9am, just checked it at 11am and still 100% battery LOL.. I haven't touched it, but doing the same on froyo would have dropped the battery to around 80% by this time regardless.
what services are you running? I've found that trillian is an awful battery hog for example, so I keep it closed unless I actually need it.
It's a reporting issue. Not sure if it's epic or GB but display is NOT right. You can have display on all the time and it will still be 3%. My guess is display reports as android system.
I think reason it drains so fast is that there is a bunch of diagnostic programs which are running. (I think they run these programs in test builds to check for problems). If you select Android System you'll see a list of them. I had the same problem with my battery draining really quickly (went back to EC05).
I've been having issues sometimes where my phone stays awake all the time even with the screen off seemingly nothing running. It wouldn't go back to normal without a reboot.
I just reflashed the EF02 modem yesterday and have not had the problem reoccur yet.
Sent from my SPH-D700 using XDA App
I had horrible battery life my first day and half with the AA i3 rom, because I had kept the EC05 modem (which always performed well for me). Flashed EF02 (and OTAed to EF10) and now get completely ridiculous battery life.
to get the best battery life install setcpu and set it for 200-800 on conservative.. my battery life is much better at that setting

[NOTICE] Battery % Reading Myth

I know there was a recent Google announcement regarding battery status wipe, however, I found the results otherwise.
Seems that many individual now trusted official Google's spokes person, I would like you take you back on our side regarding the battery reading issue.
Another reason for this post is to make sure all the ROM flashers out there understand that it is probably not the ROM's fault but the battery meter is off. On top of the above, due to the fact that recent comments to all the ROMs has been "battery for this ROM is horrible" or "This ROM has awesome battery life!" before they have fully tested the entire battery cycle.
What Google is pointing out is not necessary "wrong" but it is misleading. They are implying that users are considering the Li-ion batteries to have "memory" effect like NiMH, yes, some users may still believed so. However! To fully "wipe" the battery level, you must understand that the Li-ion crystals inside the battery does not have memory effect, it does have a "meter" that reports the battery status. This meter is used to make sure all the cells in the battery is equally consumed properly, but during a ROM install, CWM restore, these values gets confused from time to time somehow in the software level.
Now, you must think that I have no facts to say Android OS is responsible for controlling that meter's data, but my experiences has proved to be convincing.
A simple example for the case to be more clearly explained is something what I have experienced before. After new ROM installs or CWM restores, I have the following experiences regarding the battery percentage reading.
Case 1: Battery lasts almost another hour with screen on with ONLY 1% left.
Case 2: Phone turns off without reaching 0%, sometimes as high as 8% my phone turns off.
The above 2 cases happens usually when the new ROM is installed and usually would have a battery reading far off from right before the ROM install or restore. They usually result in battery not being able to be appeared fully charged or in some cases in CM9 that the percentage goes above 100%
I hope the above has convinced you that "battery wipe" is necessary from time to time or cases to cases, also note that pulling the battery when the phone freezes sometimes would case the same issue.
If you are convinced, you may use the following steps to "wipe battery status" or "calibrate" is more precised term here:
Run the phone until it turns off and cannot be turn on
Plug it into a wall charger and ONLY wall chargers (because computer USB ports will boot Atrix)
Wait until the big battery charging animation reaches 100%
Boot into recovery and wipe battery status
Reboot the phone
You should now have a "calibrated" battery meter at a hardware level where Android OS was not interfering with the meter AT ALL . You might be able to charge to 99% at most of the time, but that is fairly calibrated, can check if the voltage is at 4203mV to be sure.
My battery when on cm7 won't charge past 4196 but if I flash miui it hits 4204,it's weird.
One thing I do to is before and during flashes I make sure I'm at 100% and still plugged in on the wall charger. This helps alot.
Sent from my MB860 using xda premium
morrislee said:
I know there was a recent Google announcement regarding battery status wipe, however, I found the results otherwise.
What Google is pointing out is not necessary "wrong" but it is misleading.
Click to expand...
Click to collapse
Not trying to pick a fight, but I just wanted to point out that what they say regarding battery stats isn't misleading. Batterystats.bin and "battery status" are not related. The battery stats that everyone wipes in CWM are exactly what the Android Engineer said they are, usage statistics for battery consumption by apps. (which always get wiped any time you reach a full charge) Batterystats.bin has no effect on what battery life is being shown.
morrislee said:
Now, you must think that I have no facts to say Android OS is responsible for controlling that meter's data, but my experiences has proved to be convincing.
A simple example for the case to be more clearly explained is something what I have experienced before. After new ROM installs or CWM restores, I have the following experiences regarding the battery percentage reading.
Case 1: Battery lasts almost another hour with screen on with ONLY 1% left.
Case 2: Phone turns off without reaching 0%, sometimes as high as 8% my phone turns off.
The above 2 cases happens usually when the new ROM is installed and usually would have a battery reading far off from right before the ROM install or restore. They usually result in battery not being able to be appeared fully charged or in some cases in CM9 that the percentage goes above 100%
Click to expand...
Click to collapse
The battery reporting over 100% in CM9 was a kernel issue (checkout this commit). If you browse through the entire file for that commit, you will see the battery % reading is also handled there (search for battery_state), and you will see it's tied to the battery reaching 4200mV.
-----------------------------------------------------------------------------
Other than that, thanks for trying to clarify the "horrible battery" problem people always seem to think they have. Yesterday I saw someone asking about battery life 20 minutes after Notorious updated Neutrino, lol.
ghost_og said:
Not trying to pick a fight, but I just wanted to point out that what they say regarding battery stats isn't misleading. Batterystats.bin and "battery status" are not related. The battery stats that everyone wipes in CWM are exactly what the Android Engineer said they are, usage statistics for battery consumption by apps. (which always get wiped any time you reach a full charge) Batterystats.bin has no effect on what battery life is being shown.
The battery reporting over 100% in CM9 was a kernel issue (checkout this commit). If you browse through the entire file for that commit, you will see the battery % is also handled there (search for battery_state), and you will see it's tied to the battery reaching 4200mV.
-----------------------------------------------------------------------------
Other than that, thanks for trying to clarify the "horrible battery" problem people always seem to think they have. Yesterday I saw someone asking about battery life 20 minutes after Notorious updated Neutrino, lol.
Click to expand...
Click to collapse
haha yeah, i say that comment lol. I said it was misleading for that fact you stated above, but my point was to tell how people can fully recalibrate the battery first before considering roms have bad battery usage. Because people now thinks that android os has nothing to do with the bad battery.
Interesting for the ICS battery issue... i was able to get it to 99% and 100% when i do the above cycle though, no more > 100%. but it is good to see it has been worked on
ghost_og said:
Not trying to pick a fight, but I just wanted to point out that what they say regarding battery stats isn't misleading. Batterystats.bin and "battery status" are not related. The battery stats that everyone wipes in CWM are exactly what the Android Engineer said they are, usage statistics for battery consumption by apps. (which always get wiped any time you reach a full charge) Batterystats.bin has no effect on what battery life is being shown.
The battery reporting over 100% in CM9 was a kernel issue (checkout this commit). If you browse through the entire file for that commit, you will see the battery % reading is also handled there (search for battery_state), and you will see it's tied to the battery reaching 4200mV.
-----------------------------------------------------------------------------
Other than that, thanks for trying to clarify the "horrible battery" problem people always seem to think they have. Yesterday I saw someone asking about battery life 20 minutes after Notorious updated Neutrino, lol.
Click to expand...
Click to collapse
i try he method from the first post , and i feel mybattery is lasting longer than before i just let it die at 7:53 am from today , connect the wall charger, let charge full, because i don´t have CWM recovery , i used battery calibrator from the market to recalibrate my battery
at 8:32 pm from today with a lot of whats app facebook some games and call etc im on 70 %
thanks for the TIP !!!

WTF my battery is insane... any ideas?

Ok so I can't figure this out. My battery is kind of "retarded" for lack of a better word.
I can charge it up to 100%, reset battery stats (even if I don't the same will happen)... then let it drain. It will drain insanely fast... I mean from 100 to dead in maybe an hour sometimes...
Then I go ahead and plug it into the charger... for just 15 seconds... when I take it off the charger and turn it back on it'll have another 50% battery life, sometimes more sometimes less....
It's almost as if the battery isn't reading correctly and then the phone can't detect how much battery is left so won't let me turn it on unless I plug it in really quick...
Tried another battery and that one does the same thing.... What in gods name could be going on...
and yes.. I searched... before I hear the hit the search 2000x times.
Here is the instructions from the ExROM thread, they worked perfect for me:
Code:
--> For battery life: I think that you have to calibrate your battery.
- Run the device down until it turns itself off.
- Turn it back on and wait for it to turn itself off again.
- Remove the battery for 10 seconds.
- Replace the battery, but leave the device off.
- Charge the device until full and then for another hour.
- Enter recovery and go to advanced -> wipe battery status. Apply it.
- Run the device’s battery down until it turns itself off.
- Turn the device on and charge for at least 8 hours.
- Unplug the device, turn off, then charge for another hour.
- Unplug the device, turn on, wait 2 minutes.
- Turn off again and charge for another hour.
- Restart and use as normal.
I shall try those but who knows...
I've literally been turning the phone on, it dies the minute it hits the lock screen. Plug it in now for just 3 seconds until it says VIBRANT, it will load up shut down.. have down this about 30 times...
I'm lost on how the phone has enough juice to boot and shi*.... it's driving me nuts doing this over and over and over.. oh wait just turned on again and it's at 5%. This is stupid....
lol i will post back after I try these instructions I guess....
You MUST calibrate your battery every time you see a weird behaviour or install a new kernel. You wrote that you tried another battery, so we can exclude a premature death of the battery.
are you able to get into RECOVERY mode and stay there without it rebooting? Or even Download mode?
yo i dont understand.. didnt a google employee go out and make a public statement that batterystats.bin has NOTHING to do with battery calibration, its only used to keep the data from the settings>battery use graph throughout reboots? In the same statement, i think i remember she told aandroid users NOT to let their batteries die and charge em full cause that will damage the batt.
Sent from a cell tower to the XDA server to you.
I made a nice detailed post about this a while back, it took a google employee for people here to believe.
https://en.wikipedia.org/wiki/Memory_effect
(Keep in mind, this applies to NiCad... but the effects are the same)
Bad news bro, your battery is bad. If you full discharge/recharge all the time, it will just hasten its death. Deep cycle charging when the battery is that far gone doesn't really have the same effect.
Try coaxing it back to life by recharging it to 100% then hitting the charger again at 75% a few times. This will increase the capacitance of the battery if there is hope of life. If it doesn't improve, its life is almost over.
younix258 said:
yo i dont understand.. didnt a google employee go out and make a public statement that batterystats.bin has NOTHING to do with battery calibration, its only used to keep the data from the settings>battery use graph throughout reboots? In the same statement, i think i remember she told aandroid users NOT to let their batteries die and charge em full cause that will damage the batt.
Sent from a cell tower to the XDA server to you.
Click to expand...
Click to collapse
Correct. According to her Calibrating does pretty much nothing except make you THINK your battery is better/worse/same.
Haxel said:
I made a nice detailed post about this a while back, it took a google employee for people here to believe.
https://en.wikipedia.org/wiki/Memory_effect
(Keep in mind, this applies to NiCad... but the effects are the same)
Bad news bro, your battery is bad. If you full discharge/recharge all the time, it will just hasten its death. Deep cycle charging when the battery is that far gone doesn't really have the same effect.
Try coaxing it back to life by recharging it to 100% then hitting the charger again at 75% a few times. This will increase the capacitance of the battery if there is hope of life. If it doesn't improve, its life is almost over.
Click to expand...
Click to collapse
thanks for the interesting read, i love reading things that the mind thinks as something for a weird reason.. Placebo effect etc.
Putting your battery down to an absolute 0% will do nothing but hurt your battery. This would have worked if we were still in the 80s and 90s, but these are Li-on batteries, they work differently and it actually hurts them.
Ok so I have RESTORED the battery...
Here is what was going on after further looking. I downloaded a battery stat/drain program to see what exactly was going on...
Under a load the battery mV will change drastically, then once it settles down the mV will actually rise making the % rise...
So I completely killed the battery, I mean dead.. Restarted the phone, plug it in for just a second.. I took it to the point that I killed the SOB battery.
I then charged it up, and while charging I would use the battery drain program. the mV would change drastically and I did this every 10%.
So far so good, the phone has been on for 4 hours now and i've only drained 8%... I will see how it continues.
I've also been resetting my battery stats not because I believe it relates the phone to the actual battery % but the % would fluctuate on the phone, and I thought the phone was saying "batterys dead don't turn on" kind of thing...
Ok. Again.
Here is a more in-detail article with a quick google.
http://www.atomicmods.com/Categories/QandA-Batteries.aspx
How long will these batteries last?
Lithium-based batteries have a lifetime of 2-3 years. The clock starts ticking as soon as the battery comes off the manufacturing line. The capacity loss manifests itself in increased internal resistance caused by oxidation. Eventually, the cell resistance will reach a point where the pack can no longer deliver the stored energy; although the battery may still contain ample charge. Increasing internal resistance is common to cobalt-based lithium-ion. The speed by which lithium-ion ages is governed by storage temperature and state-of-charge. Figure 1 illustrates the capacity loss as a function of these two parameters.
Click to expand...
Click to collapse
Although, there has been arguments for years about Li-ion "memory". Li-ions are not afflicted with the "memory" issues of other chemical types. What they are afflicted with is the inability to hold a consistent current under stress/load with age/oxidation (aging effect of the Li-ion batteries). This is where your battery sits. On the precipice of death. You may get another year or two out of it (if you're lucky.. really more like a few months) with a few correct charging cycles, but that is it.
Bringing a Li-ion to near 0 and back does not help the battery, it is 100% a placebo effect with short term gains at best. A common cause of your particular problem...
Lithium-ion batteries are often exposed to unfavorable temperatures, and these include leaving a cell phone in the hot sun or operating a laptop on the power grid. Elevated temperature and allowing the battery to sit at the maximum charge voltage for expended periods of time explains the shorter than expected battery life. Elevated temperature and excessive overcharge also stresses lead and nickel-based batteries. All batteries must have the ability to relax after charged, even when kept on float or trickle charge.
Click to expand...
Click to collapse
http://batteryuniversity.com/learn/article/how_to_store_batteries
I'm giving random googling as I know it's difficult to believe a random person on the internet. No two type of manufactured batteries are created/engineered the same, but I'm basing my statements of chemical composition and the basic fundamentals of the Li-ion battery tech.
younix258 said:
yo i dont understand.. didnt a google employee go out and make a public statement that batterystats.bin has NOTHING to do with battery calibration, its only used to keep the data from the settings>battery use graph throughout reboots? In the same statement, i think i remember she told aandroid users NOT to let their batteries die and charge em full cause that will damage the batt.
Sent from a cell tower to the XDA server to you.
Click to expand...
Click to collapse
+1
Sent from my SGH-T959 using XDA
Most of these battery calibration techniques sound like a practical joke.
the only way you'll truly get a perfect idea of what your battery life is going to be is to drop the phone in the toilet.
Sent from my SAMSUNG-SGH-T989 using XDA

Nexus 7 Battery issues

Haven't switched from the OEM charging cord so I don't know why my battery meter showed that I remained at 22% for more than 3 hours...
All day yesterday the only time the percentage would go above that was when I put the tablet down completely, killed all apps and processes and shut off wifi....I've never had to do so much just to see an increase So I attempted to recalibrate and wipe battery stats in cwm for the first time as I have done on all my other devices...
With most if not all devices the fastest way to charge is with the device powered off....for the strangest reason the N7 charges faster with the power on. Ive had this thing plugged in for 5 hours from a fully discharged state and the batter meter only reads half....whats taking so long? With the device on all i need is 2.5-3 hours....Can someone explain this as i have combed Google search like mad looking for an answer...
Sent from my Nexus 7 using xda app-developers app
oneG said:
All day yesterday the only time the percentage would go above that was when I put the tablet down completely, killed all apps and processes and shut off wifi....I've never had to do so much just to see an increase So I attempted to recalibrate and wipe battery stats in cwm for the first time as I have done on all my other devices...
Click to expand...
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Looks like you missed the memo...
Wiping battery stats does not affect battery indication in any way, shape, or form, nor can you actually ”recalibrate” your battery. The misinformation regarding wiping battery stats was emphatically debunked by Google's Android team about a year ago.
Rather than wasting time with snake oil such as ”calibration” and wiping battery stats, more viable solutions are a factory reset or ensuring your battery connector is fully seated on the mainboard.
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