How to properly calibrate an iPhone 3GS?

pcs are junk

macrumors 65816
Original poster
Sep 28, 2009
1,044
0
Hi guys, I have never calibrated my battery, I was just wondering how to go about it correctly. I know that I have to charge it to 100% then let it drain to zero, but when it shuts off, do I just drain it to the point where the red battery thing comes up, or to the point where this is no juice at all? Any help would be so much appreciated! Thanks in advance!
 

ntrigue

macrumors 68040
Jul 30, 2007
3,804
1
Hi guys, I have never calibrated my battery, I was just wondering how to go about it correctly. I know that I have to charge it to 100% then let it drain to zero, but when it shuts off, do I just drain it to the point where the red battery thing comes up, or to the point where this is no juice at all? Any help would be so much appreciated! Thanks in advance!
I go to 8% before I charge mine back up. My method seems to do the trick.
Absolutely incorrect information. You charge the battery to 100% leave it that way for two hours. Unplug and wait until it dies (spinning wheel and empty battery in center of screen) then wait two hours before plugging-in and charging to 100%.
 

ajohnson253

macrumors 68000
Jun 16, 2008
1,751
0
Absolutely incorrect information. You charge the battery to 100% leave it that way for two hours. Unplug and wait until it dies (spinning wheel and empty battery in center of screen) then wait two hours before plugging-in and charging to 100%.
Why wait 2 hours before plugging it in when it's already dead?
 

ntrigue

macrumors 68040
Jul 30, 2007
3,804
1
Why wait 2 hours before plugging it in when it's already dead?
The LiIon chipsets thinks it's dead when it actually has 2-3% remaining. You're trying to tell the phone what dead 'really' is and what 'full' really is.
 

ajohnson253

macrumors 68000
Jun 16, 2008
1,751
0
So pretty much when it's plugged in and reached a 100% charge. Keep it on the charger for an extra 2 hours at 100% then put it to use?
 

muttonhead411

macrumors member
Oct 31, 2008
74
0
@ntrigue lithium ion batteries that are used in the iphone should never be fully discharged as you have described. The circuitry in place in the iphone is there for a reason, and that is to prevent "deep discharges" from occurring. This is so because deep discharging shortens the life of your battery. Note this is different from your battery life, which is what the OP is referring to.

The point of calibration is to help the circuitry in the phone estimate your battery life. It does NOT have any imaginary good effect on your battery itself. They do not suffer from memory problems as do your laptop batteries
 

davehutch

macrumors 6502a
Mar 5, 2009
671
20
Croxley, Herts
The LiIon chipsets thinks it's dead when it actually has 2-3% remaining. You're trying to tell the phone what dead 'really' is and what 'full' really is.
The phone needs to shut down at 3% to preserve the working life of the battery. You should never run a Li-Ion battery down to zero
 

ajohnson253

macrumors 68000
Jun 16, 2008
1,751
0
@ntrigue lithium ion batteries that are used in the iphone should never be fully discharged as you have described. The circuitry in place in the iphone is there for a reason, and that is to prevent "deep discharges" from occurring. This is so because deep discharging shortens the life of your battery. Note this is different from your battery life, which is what the OP is referring to.

The point of calibration is to help the circuitry in the phone estimate your battery life. It does NOT have any imaginary good effect on your battery itself. They do not suffer from memory problems as do your laptop batteries
that sounds right
 

ntrigue

macrumors 68040
Jul 30, 2007
3,804
1
@ntrigue lithium ion batteries that are used in the iphone should never be fully discharged as you have described. The circuitry in place in the iphone is there for a reason, and that is to prevent "deep discharges" from occurring. This is so because deep discharging shortens the life of your battery. Note this is different from your battery life, which is what the OP is referring to.

The point of calibration is to help the circuitry in the phone estimate your battery life. It does NOT have any imaginary good effect on your battery itself. They do not suffer from memory problems as do your laptop batteries
The phone needs to shut down at 3% to preserve the working life of the battery. You should never run a Li-Ion battery down to zero
that sounds right
I understand the intricacies of NiCad vs. LiIon. Although LiIon is 'happiest' between 20-80% capacity and best stored at 50% that is beyond the undeniable fact that once every two months the procedure I described should be followed to maintain ACCURACY.

http://www.batteryuniversity.com/


- Avoid frequent full discharges; regular partial discharges and an occasional full discharge are better. Lithium batteries have no charge “memory”, unlike NiCd batteries, so frequent recharging does no harm.

- Carry out a deliberate full discharge once every 30 charges, you can do this by simply running the battery down in the equipment (if you have power management enabled switch it off temporarily and make sure you are not running any critical software). An advantage of this approach is that it helps calibrate the battery fuel gauge and avoids premature hybernation.


http://forums.macrumors.com/showthread.php?t=525741

"#4 - Every two months, make sure you fully charge and fully drain the battery, in one cycle. This calibrates your battery indicator. If you fail to do this, your indicator will become inaccurate. Calibrating your battery does not improve battery life."
 

thelatinist

macrumors 603
Aug 15, 2009
5,933
49
Connecticut, USA
ntrigue, your advice is mostly good. People aren't saying that one shouldn't recalibrate the battery. What people are objecting to is your advice to allow the phone to sit for 2 hours fully-discharged: "then wait two hours before plugging-in and charging to 100%." This is bad advice, since you run the risk of damaging your battery by excessively discharging it. Since even when turned off your phone will continue to discharge its battery, the phone should be plugged in as soon as the automated circuitry shuts it off to protect against deep discharge.

Not only that, but doing what you describe will actually result in an inaccurate battery meter. The purpose of battery meter calibration is to get an accurate measure of the usable life of your battery. Allowing the battery to continue to discharge after shutoff will trick the battery meter into thinking the bottom of the battery cycle is lower than it actually is. This will cause your battery meter to decrement slower, but it will not extend your battery life; it will only cause it to shut off early (with several % still left on the battery meter).

By all means, discharge to automatic shutoff and charge to 100% + 2 hrs. But don't wait 2 hrs after automatic shutoff to plug it in.
 

-aggie-

macrumors P6
Jun 19, 2009
16,793
50
Where bunnies are welcome.
ntrigue, your advice is mostly good. People aren't saying that one shouldn't recalibrate the battery. What people are objecting to is your advice to allow the phone to sit for 2 hours fully-discharged: "then wait two hours before plugging-in and charging to 100%." This is bad advice, since you run the risk of excessively discharging your battery. Since even when turned off your phone will continue to discharge its battery, the phone should be plugged in as soon as the automated circuitry shuts it off to protect against deep discharge.

Not only that, but doing what you describe will actually result in an inaccurate battery meter. The purpose of battery meter calibration is to get an accurate measure of the usable life of your battery. Allowing the battery to continue to discharge after shutoff will trick the battery meter into thinking the bottom of the battery cycle is lower than it actually is. This will cause your battery meter to decrement slower, but it will not extend your battery life; it will only cause it to shut off early (with several % still left on the battery meter).

By all means, discharge to automatic shutoff and charge to 100% + 2 hrs. But don't wait 2 hrs after automatic shutoff to plug it in.
Actually what he advised could actually make the battery where it couldn't take a charge, essentially ruining the battery (by waiting 2 hours to charge it).
 

thelatinist

macrumors 603
Aug 15, 2009
5,933
49
Connecticut, USA
Actually what he advised could actually make the battery where it couldn't take a charge, essentially ruining the battery (by waiting 2 hours to charge it).
Yes, that's what I meant by warning about "deep discharge." Deep-discharge of a Li-Ion battery can absolutely cause damage which can greatly decrease the capacity and life of the battery. I won't say occasionally running out your battery when you are out of reach of your charger will completely ruin it (I myself have been surprised by automatic shutoff and had to wait until I got home to charge), but one should never intentionally allow the battery to discharge past automatic shutoff.
 

ntrigue

macrumors 68040
Jul 30, 2007
3,804
1
My battery repeatedly shutoff at 2-3% after calibration. It wasn't until I used the two additional hour method that I saw 1% for 5 minutes before it died. But yes, I agree and have heard of people leaving iPhones for weeks and being unable to charge.

I just took my original iPhone out of a drawer and it turned on after 10 minutes plugged-in. Thats months of dead LiIon.
 

thelatinist

macrumors 603
Aug 15, 2009
5,933
49
Connecticut, USA
My battery repeatedly shutoff at 2-3% after calibration. It wasn't until I used the two additional hour method that I saw 1% for 5 minutes before it died. But yes, I agree and have heard of people leaving iPhones for weeks and being unable to charge.

I just took my original iPhone out of a drawer and it turned on after 10 minutes plugged-in. Thats months of dead LiIon.
Cut it out. What foolish things you want to do to your iPhone is one thing; what you advise others is another.
 

tctony

macrumors 6502a
Jun 15, 2009
684
0
I think you guys are wrong. I believe you do allow the phone to sit fully discharged for a few hours.

http://www.apple.com/batteries/iphone.html

"Be sure to go through at least one charge cycle per month (charging the battery to 100% and then completely running it down)."

http://support.apple.com/kb/HT1490

This is geared towards the notebooks, but specifically mentions "lithium based batteries."

"Turn off the computer or allow it to sleep for five hours or more."


Two hours of discharged seems about right for the phone. The point is to show the battery what "fully charged" is and what "fully drained" is. When uncalibrated, the phone can shut off with some juice left in it. You allow it to sit and drain fully to know what empty actually is. You guys are ludicrous if you think this is going to actually hurt the phone if you do it once a month.
 

davehutch

macrumors 6502a
Mar 5, 2009
671
20
Croxley, Herts
I think you guys are wrong. I believe you do allow the phone to sit fully discharged for a few hours.

http://www.apple.com/batteries/iphone.html

"Be sure to go through at least one charge cycle per month (charging the battery to 100% and then completely running it down)."

http://support.apple.com/kb/HT1490

This is geared towards the notebooks, but specifically mentions "lithium based batteries."

"Turn off the computer or allow it to sleep for five hours or more."


Two hours of discharged seems about right for the phone. The point is to show the battery what "fully charged" is and what "fully drained" is. When uncalibrated, the phone can shut off with some juice left in it. You allow it to sit and drain fully to know what empty actually is. You guys are ludicrous if you think this is going to actually hurt the phone if you do it once a month.
No, no, no...if you do that, all the sludge at the bottom of the tank gets dragged up through the carburettor ;)
 

ajohnson253

macrumors 68000
Jun 16, 2008
1,751
0
So overall it's not good to do a deep discharge correct haha. Didn't think this thread would still be going. So I'm just going to go with, deep discharging is a no no.
 

UnLiMiTeD558

macrumors 6502a
Dec 20, 2009
938
507
Bc Canada
to be safe, just drain it till the phone dies, the recharge, it does not say on the apple site to leave the phone an additional 2 hours after it dies so i wouldnt recommend doing so
 

ntrigue

macrumors 68040
Jul 30, 2007
3,804
1
Cut it out. What foolish things you want to do to your iPhone is one thing; what you advise others is another.
http://www.batteryuniversity.com/parttwo-34.htm

Avoid frequent full discharges because this puts additional strain on the battery. Several partial discharges with frequent recharges are better for lithium-ion than one deep one. Recharging a partially charged lithium-ion does not cause harm because there is no memory. (In this respect, lithium-ion differs from nickel-based batteries.) Short battery life in a laptop is mainly cause by heat rather than charge / discharge patterns.

Batteries with fuel gauge (laptops) should be calibrated by applying a deliberate full discharge once every 30 charges. Running the pack down in the equipment does this. If ignored, the fuel gauge will become increasingly less accurate and in some cases cut off the device prematurely.
 

thelatinist

macrumors 603
Aug 15, 2009
5,933
49
Connecticut, USA
Batteries with fuel gauge (laptops) should be calibrated by applying a deliberate full discharge once every 30 charges. Running the pack down in the equipment does this. If ignored, the fuel gauge will become increasingly less accurate and in some cases cut off the device prematurely.
I repeat, nobody is saying not to calibrate the battery! What we are saying is that you should not discharge the battery past the automatic shutoff when you do it. The procedure you advocated called for allowing the battery to continue to discharge for two hours after the phone automatically shut off, and that is damaging to your battery. It is only that part of what you said that I and everyone else here is objecting to, and nothing you've quoted disagrees with us. In fact, the page you cite says specifically of calibrating the battery, "Letting the battery run down to the cut-off point in the equipment will do this" [emphasis added]. It says nothing about continuing to let it discharge past the automatic cut-off. I am not sure why this distinction is lost on you, but it is a very important one for the life of a Li-ion battery.
 

ntrigue

macrumors 68040
Jul 30, 2007
3,804
1
I repeat, nobody is saying not to calibrate the battery! What we are saying is that you should not discharge the battery past the automatic shutoff when you do it. The procedure you advocated called for allowing the battery to continue to discharge for two hours after the phone automatically shut off, and that is damaging to your battery. It is only that part of what you said that I and everyone else here is objecting to, and nothing you've quoted disagrees with us. In fact, the page you cite says specifically of calibrating the battery, "Letting the battery run down to the cut-off point in the equipment will do this" [emphasis added]. It says nothing about continuing to let it discharge past the automatic cut-off. I am not sure why this distinction is lost on you, but it is a very important one for the life of a Li-ion battery.
I implore you to explain why the Apple laptops require a five hour discharge while the iPhone calibrates with an instant discharge?!
 

mavis

macrumors 601
Jul 30, 2007
4,068
395
Tokyo, Japan
Wirelessly posted (iPhone 3GS (JB3.1.2, unlocked): Mozilla/5.0 (iPhone; U; CPU iPhone OS 3_1_2 like Mac OS X; en-us) AppleWebKit/528.18 (KHTML, like Gecko) Version/4.0 Mobile/7D11 Safari/528.16)
I implore you to explain why the Apple laptops require a five hour discharge while the iPhone calibrates with an instant discharge?!

It's magic.

Seriously, what difference does it make? You're right and everyone else is wrong OR everyone else is right and you're wrong. Who cares? Completely discharge your battery every couple of months, and then charge it back up. Problem solved.