Firstly.... go here and read this -
http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries
The battery is fully charged when it is at 4.2 Volts and fully discharged at some predefined voltage (Lets say 3 volts).
The phone can measure these voltages directly from the battery. To see the voltage of your battery type *#*#4636#*#* into your phone and go to battery information.
If all that is so then what is the point or need of "recalibrating" and deleting battery stats and all that.
It seems logical to me that battery stats is just the place where your battery usage history is stored and nothing else.
Can someone confirm this or convince me otherwise?
(I rotate between 3 batteries and cannot grasp the idea that my phone can't consistently measure the charge level of the battery and operate accordingly.)
Measuring the Voltage to get the charge level is not very accurate, and has to be done with no load on the battery (that is, when its not in your phone).
So the phone has to count "energy used from"/"energy stored in" the battery for an accurate display. (called "Coloumb counter")
Did some test
I did a test on new a battery a while ago. Measure voltage when the battery completely empty and fully charged.
Empty battery
1% remaining, using SystemPanel
Take the battery out and measure it with Multimeter
Fully charged
100% charged
Again, measure it with Multimeter
The voltage showed on the phone using SystemPanel app is quite accurate with 0.04V margin of error. Most smart electronic measure lithium battery capacity according to the remaining voltage. In this case, fully charged SGS is 4.2V, empty is 3.5V.
Me too, don't know why we have to delete batterystats.bin to recalibrate battery indicator But I do know that SGS keep track on power consumption on each of its component/application. Its a little bit silly if SGS reads batterystats.bin and display it as battery indicator.
Yet again how is this android development.
Sent from my GT-I9000 using XDA App
xufos said:
I did a test on new a battery a while ago. Measure current when the battery completely empty and fully charged.
Empty battery
1% remaining, using SystemPanel
Take the battery out and measure it with Multimeter
Fully charged
100% charged
Again, measure it with Multimeter
The current showed on the phone using SystemPanel app is quite accurate with 0.04V error margin. Most smart electronic measure lithium battery capacity according to the remaining current. In this case, fully charged SGS is 4.2V, empty is 3.5V.
Me too, don't know why we have to delete batterystats.bin to recalibrate battery indicator But I do know that SGS keep track on power consumption on each of its component/application. Its a little bit silly if SGS reads batterystats.bin and display it as battery indicator.
Click to expand...
Click to collapse
Thanks for that, but you were actually measuring the Voltage, not current (Amperes).
In any case, for laptop Li-ion batteries there is normally a capacity counter (Coulomb counter) that reports the capacity in terms of mAh (milli-ampere hours). It can normally report the remaining capacity, maximum capacity, design capacity, and can be used to measure the *actual* power drain (in terms of Watts).
I wonder if Android has APIs that let apps access that kind of information?
Not really sure about this, but:
Phone seems to measure both voltage & discharge speed, "predicting" remaining charge.
It happens that after a flash battery indicator jumps to a higher value (not compatible with the couple of minutes of dc connection it had), and fall to a way too low value after any battery intensive task (a few minutes of audio call are enough), once more not compatible with the real usage.
I should inspect android code to be shure of this, but I suspect batterystats.bin is used to keep track of battery usage and to this sort of prediction, while a firmware flash seems to mess somehow the measurement.
Edit: this is based on my direct experience, even if on just "empirical" tests. I'll take a look to code asap
'mkay, battery talk... always interesting to see what people make of this.
Let's help out all the misunderstandings here and start with the basics
First of all: read the basics on Li-ion batteries:
http://electronics.howstuffworks.com/lithium-ion-battery.htm
second:
you DON'T measure your voltage when your battery is disconnected. Because it will rise to the normal values of the battery after a while. When you connect it, and use it, the voltage will lower. Compare it to a garden hose. if you let water run out, the presure drops and water starts flowing (presure is voltage, flowing is the current). If you measure the presure when there is no water running, the presure will always mount to the default value, even if there is "not much water left in the tank". But when it starts running again, it could very well run out very fast. So in comparison: voltage says something, but only when you "use" it.
Third:
When a battery ages, it's characteristics change, it will be full... and then all at once, empty. It's not linear. So calculating the capacity is always a bit "guessing". (compare it to stones in your water tank... they don't give you water, the tank doesn't change, but all of a sudden, you're out of water).
conclusion:
capacity of a battery is a very tricky thing to do, it's a combination of voltage, current, age... so the best way to determine capacity is by using the history of the battery as the "guide" to the future. Resetting the battery statistics will remove that history and your phone will have to "learn" it's behavior again. If you don't reset your stats, your values will become more reliable over time (depending of course on the time the stats are kept )
For those who speak dutch, i put a complete battery description/howto/misunderstandings post on www.modelbouwforum.nl (search for posts of "harrydg")
If there are more questions or so, just ask, i'll try to help out as much as possible...
wow harrydg that's great explanation, wish you were my physics teacher back in high school
someone add this post to the main FAQ!
I just wanna write it in a simpler way:
You've access to the battery stats from the kernel. And of course its current consumption which is measured not voltage. Voltage doesn't tell all that much. During high draws your voltage (at the battery level) can fluctuate quite a bit.
There's a regulator (or probably a bunch of them) get a stable voltage no matter what the input voltage is (well, still it has to be in the 3.3/5v range probably else the regulator burns)
Anyway, that's also why the battery stats have to be calibrated, while you can measure how much current is used (in maH aka milli amp per hour, or in mA aka "instant" milli amps), you don't know the battery capacity.
Not only the battery capacity changes from battery to battery but it also changes during the life time of the battery.
The *only* way to calibrate the battery, is to delete the stats, have a fully charged phone and let it drain out the battery until it turns off. That way the kernel will measure for example 1457mah used until it ran out of juice, and that's your battery capacity then. Having the full capacity allows the kernel to give you a rather precise estimate of your current battery status (eg "80%" that you see on the top of the screen) (of course the actual calculation is a bit more complicate but that's the basics)
If calibration stats storage is changed for any reason (probably kernel upgrade or just a whacky samsung implementation that gets corrupted for some reason) you need to delete it and make a new one to recalibrate.
If you want to make it simpler, make it at least correct...
"Anyway, that's also why the battery stats have to be calibrated, while you can measure how much current is used (in maH aka milli amp per hour, or in mA aka "instant" milli amps), you don't know the battery capacity."
First of al, it's mAh, which means milli ampere hour, NOT per hour, that would be mA/h, which it is not.
mA is milli ampere, which is a current
there is a significant difference between the 2.
the first is "capacity"
the second is "current"
it's like a bottle. The capacity is 2l and you pour at 1l per minut...
so... make it simple please...
My guess is, that android is measuring the known min and max by the battery reported values, stores them and calculates the percentages.
So it is device and battery independent.
harrydg said:
If you want to make it simpler, make it at least correct...
"Anyway, that's also why the battery stats have to be calibrated, while you can measure how much current is used (in maH aka milli amp per hour, or in mA aka "instant" milli amps), you don't know the battery capacity."
First of al, it's mAh, which means milli ampere hour, NOT per hour, that would be mA/h, which it is not.
mA is milli ampere, which is a current
there is a significant difference between the 2.
the first is "capacity"
the second is "current"
it's like a bottle. The capacity is 2l and you pour at 1l per minut...
so... make it simple please...
Click to expand...
Click to collapse
Sorry a typo and no caps deserve heavy flaming
bilboa1 said:
Sorry a typo and no caps deserve heavy flaming
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Click to collapse
hehe, sorry for the rant, but if you want to put it simple, make sure the terminology and abbreviations are correct. If not, people will take over the mistakes and conversations will go totally wrong because of misunderstandings...
Thanks very much for the feedback guys. It makes more sense now.
It's using batterystats to get familiar with discharge rates in order to give an accurate estimation of remaining charge and a prediction of when it will run dry.
Can it misreprasent these values and forcibly power down the phone when there is still charge remaining?
And likewise can it stop the charging process prematurely, estimating the battery to be at 100% charge when it is lower?
Is this the reason to recalibrate?
Heres one thing what I noticed about the battery stats, some say deleting it fixes the guage and does not really recalibrate the battery, I really doubt there is a way for end users to do that, even if you never delete the battery stats bin and your drain is pretty fast, it significantly slows down when your battery hits around 25~35, the lower the power on the battery the more accurate it can be represented regardless of the calibration. This is applicaple for the SGS only.
Now it comes to the question..
If the phone create battery stats every time the phone reboot, then when is the best time to delete and the best way to calibrate?
This is what I normally do..
..delete stats at 5%, let it run dry til it turn itself off, dont turn on but connect the charger til it fully charged. Turn phone on and ill have fully charged battery along with fresh stats.
Is this correct?
vosszaa said:
Now it comes to the question..
If the phone create battery stats every time the phone reboot, then when is the best time to delete and the best way to calibrate?
This is what I normally do..
..delete stats at 5%, let it run dry til it turn itself off, dont turn on but connect the charger til it fully charged. Turn phone on and ill have fully charged battery along with fresh stats.
Is this correct?
Click to expand...
Click to collapse
On the SGS theres no real point in deleting it, unless you dont really wanna see the battery go down to 35% and stay there for a while, how ever busted your battery indicator is it gets very accurate as the lower it goes.
I never found batterystats made any difference. What did make a difference is the rom or kernel, what widgets, lagfix e.t.c
If you get more than 1% battery drain per 5hr standby then something is wrong
Sent from my GT-I9000 using XDA App
android53 said:
I never found batterystats made any difference. What did make a difference is the rom or kernel, what widgets, lagfix e.t.c
If you get more than 1% battery drain per 5hr standby then something is wrong
Sent from my GT-I9000 using XDA App
Click to expand...
Click to collapse
I find that conclusion quite flawed.
First of all, what's your definition of standby?
3g on? Wireless on? Autosync on? There are also noticeable differences between different firmwares and between 2.1 and 2.2.
In addition, most people are reporting somewhere around 1% per 1 hour standby or 1% per 2 hour standby, which it what I have been experiencing as well. Sometimes, apparently for no reason, it can drain faster than that, maybe 1% per 0,5 hour or more. I think this might be some widgets fault.
1%/5h standby 3g no sync
i get 1%/2h with data and sync
Depends on your reception, im just basically saying if your losing say 8% battery overnight or more then something is wrong unless your polling several push email accounts
For some reason once my phone hits 8% battery life it drops to 2% immediately.
This happens on viperxl & cm, so its not ROM related.
Any ideas on how to fix it? Is there a way to recalibrate the battery ?
Sent from my One X using Tapatalk
There's nothing wrong with your battery. That's normal behaviour when the battery is at such a low level. The battery percentage is never an exact value, it's only an estimate based on the current voltage that is being reported by the battery. When a battery is that low it isn't abnormal at all for it to jump down drastically like that.
On a side note, unless you're performing an initial charge cycle after flashing a new ROM you really shouldn't let your battery deplete to such a low level. With this specify type of battery technology it's quite bad for it and will actually affect the long term life of the battery. The preferred method of charging is to do regular top up charges from anywhere between ~80% and ~30% battery level right up to the 100% mark.
Sent from my Evita
The_Zodiac said:
Any ideas on how to fix it? Is there a way to recalibrate the battery ?
Click to expand...
Click to collapse
There is no such thing as "recalibrating the battery". This term is sometimes used by folks who confuse Li ion technology with old NiCad batteries that need to be "conditioned".
What you may mean is recalibrating the battery meter, which has to do with software, not battery chemistry. Battery meter is usually not accurate after a ROM flash, and should be recalibrated. This is done by charging to 100% (let it sit for half hour or so at full, to ensure any saturation charge is achieved) then deplete until around 10 or 20%.
Other than that, the meter is as accurate as its going to get. As timmaaa already stated, the battery % is just an inaccurate approximation of the amount of usage left that corresponds to various voltages. It often can't be trusted to be accurate to within 1% (or even 5%) increments. And also as timmaa stated, you should not be draining your battery that low on a frequent or habitual basis, as its harmful to the long term life of the battery. Charge frequently.
I have a POCO F3 that I've purchased about a month and half ago. I've dialed the code *#*#6485#*#* to check my battery health by diving the current battery capacity for the factory battery capacity and then by multiplying that result by 100 and it was at 92.7%. Is it normal after about 6 weeks of use with the phone?
crazy_penguin said:
I have a POCO F3 that I've purchased about a month and half ago. I've dialed the code *#*#6485#*#* to check my battery health by diving the current battery capacity for the factory battery capacity and then by multiplying that result by 100 and it was at 92.7%. Is it normal after about 6 weeks of use with the phone?
Click to expand...
Click to collapse
Check what cpuz reports. To me that doesn't look normal, something is with the battery sensors. Have you installed any custom kernel or anything that might play with "Advanced Charge Control Interface" ?
LAST_krypton said:
Check what cpuz reports. To me that doesn't look normal, something is with the battery sensors. Have you installed any custom kernel or anything that might play with "Advanced Charge Control Interface" ?
Click to expand...
Click to collapse
What is cpuz? I haven't installed anything
LAST_krypton said:
Check what cpuz reports. To me that doesn't look normal, something is with the battery sensors. Have you installed any custom kernel or anything that might play with "Advanced Charge Control Interface" ?
Click to expand...
Click to collapse
Oh ok. It's an app. I've installed and this is what appears about my battery's info
@crazy_penguin
IMO you can't compute Battery health at your own - at least not the way you did it. And Android OS also can't.
Battery health - also called battery lifespan - simply tells you amount of time your battery can last until it needs to be replaced / fully recharged.
Battery health always is expressed as estimated time - in hours and minutes, not as percent of whatever.
More info here:
Battery Life Calculator: How Long Does A Battery Last? (Ah, V, Hours)
In our article discussing Ah (ampere-hours) and Wh (watt-hours), we got a ton of questions about the longevity of batteries. The question “How long does a battery last?” was a predominant one. To help everybody trying to calculate how long will a battery last, we have created a Battery Life...
learnmetrics.com
crazy_penguin said:
I have a POCO F3 that I've purchased about a month and half ago. I've dialed the code *#*#6485#*#* to check my battery health by diving the current battery capacity for the factory battery capacity and then by multiplying that result by 100 and it was at 92.7%. Is it normal after about 6 weeks of use with the phone?
Click to expand...
Click to collapse
It's not normal, in that period, it shouldn't decrease a full 2%. Sometimes, a malfunctioning OS may report false calculations.
On my old device, I used two different systems, they showed different calculations of battery health.
One OS showed ~68-67%, the other showed 76.4%. I don't trust calculations anyway.
Mohamedkam000 said:
It's not normal, in that period, it shouldn't decrease a full 2%. Sometimes, a malfunctioning OS may report false calculations.
On my old device, I used two different systems, they showed different calculations of battery health.
One OS showed ~68-67%, the other showed 76.4%. I don't trust calculations anyway.
Click to expand...
Click to collapse
Wipe cahce partiton or even do a factroy reset. If you have TWRP check what battery % it shows there.
jwoegerbauer said:
IMO you can't compute Battery health at your own. And Android OS also can't.
Battery health - also called battery lifespan - simply tells you amount of time your battery can last until it needs to be replaced.
Click to expand...
Click to collapse
Meh, stop worrying.
An Li useful life is about 200 full charge cycles (0-100%).
Partial midrange charging cycles (40-62%) can yield hundreds even thousands more full charge cycles to the battery's lifespan.
Estimate battery health by SOT and by drain reported overnight.
When your SOT dips much below 80% of it's new capacity, the Li is degraded and at the end of its usable lifespan.
Replace before it fails and damages the phone.
Any battery swelling in a failure.
Cell phone Li's hate high cell voltage, temperatures and high discharge rates.
Keep charge cycles between 40-72% to extend life.
Li's love frequent midrange power cycling.
Avoid discharging below 20% or constantly charging to 100%.
Minimum start charge temp is 72F, 82-92F is best. Low temp charging can cause Li plating.
Never attempt to charge a Li below 40F!!!
If battery temp is exceeding 100F use cooling.
Apps like Accubattery's history logging are useful is seeing actual battery discharge and charging times. Useful is spotting excessive battery drain.
Eventually the battery will need replacement. On a heavily used phone that's 1-2 years.
No big deal... just do it!
Always use a new OEM seal if the phone is watertight.
LAST_krypton said:
Wipe cahce partiton or even do a factroy reset. If you have TWRP check what battery % it shows there.
Click to expand...
Click to collapse
Oh don't worry, I never considered this a problem, phone was just fine in everything except at the health calculation.
I'm just showing the OP that maybe it has something to do with the OS.
LAST_krypton said:
Wipe cahce partiton or even do a factroy reset. If you have TWRP check what battery % it shows there.
Click to expand...
Click to collapse
how do I wipe cache?
Try discharging until it dies then charge to 100%
Repeat 2 more times to recalibrate the battery % indicator.
Not worth the trouble though...
blackhawk said:
Try discharging until it dies then charge to 100%
Repeat 2 more times to recalibrate the battery % indicator.
Not worth the trouble though...
Click to expand...
Click to collapse
so it's not worth doing it? I shouldn't worry about those 93%?
crazy_penguin said:
so it's not worth doing it? I shouldn't worry about those 93%?
Click to expand...
Click to collapse
As long it shutdown at 5% and charges to 100% there's nothing that should to be done.
A sudden capacity drop, erratic fast charging indicate a battery failure.
A swollen battery is a failure.
You have none of these symptoms.
it's fine, I agree
I don't think it's typical, what you use it for is dependent? Maybe if intensive video processing and tweaking, playing and watching live?
May Anyone ask how something functions, too? What could I get to learn about the quality and capability of your real battery?