iPhone 3G Battery Guide and Charging Tips

Aug 13, 2008
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This thread was created to help maximize the potential of your iPhone's battery. If you read something you disagree with, disagree. If you wish to have something added to this original post, please comment and state what information should be added. I take no responsibility if you damage your iPhone by doing something mentioned in this thread.

Please don't flame.

Rated Battery Life

iPhone 3G
Talk Time - 3G 5 hours / EDGE 10 hours
Internet - 3G 5 hours / WiFi 6 hours
Video - 7 hours
Audio - 24 hours
Standby Time - 300 hours

iPhone 2G (Original)
Talk Time - EDGE 8 hours
Internet - WiFi 6 hours
Video - 7 hours
Audio - 24 hours
Standby Time - 250 hours

Power Saving Tips

- Always go to the home screen before putting your iPhone in standby mode. If you are running an App and hit the Sleep/Wake button to turn the screen off, the application will still be running in the background and can severely drain your battery.
- Disable 3G on long calls (Ex: businesss calls, calling your cable company, or calling ATT Customer Service :p). Call quality on EDGE is quite good compared to 3G.
- If your apartment / house has a weak 3G signal, definitely turn off 3G until you leave your home. My apartment has a very weak 3G signal. The phone switches networks constantly if I have 3G enabled, which murders my battery. I use EDGE while I'm at home w/ WiFi for data. When I leave my home, I turn on 3G.
- Enable WiFi in your apartment / house when WiFi is available. Use WiFi instead of 3G or EDGE for web browsing. WiFi is (with a strong signal) faster than 3G or EDGE. WiFi also uses significantly less battery power than any cellular network.
- If you only use WiFi hotspots, keep WiFi disabled. Enable WiFi when you enter a hotspot.
- Always use 3G for web browsing instead of EDGE. Due to the increased amount of time EDGE takes to access a web page, you will actually use up more battery life with EDGE than with 3G.

This graph demonstrates why it doesn't make sense to use EDGE for web browsing vs. 3G or WiFi. Realize that 3G is usually at least 2X as fast as EDGE.


Here's a numerical explanation. (Web Pages Accessed #'s are theoretical, but based on 3G's 2X speed)
3G Web = 197 Minutes Browsing Time | 400 Web Pages Accessed
EDGE Web = 243 Minutes Browsing Time | 246 Web Pages Accessed

- Disable Location Services (GPS). This seems to have a huge impact on battery. Keep location services off until you need to use it. When Location Services are ON, your GPS antenna is activated. Even if you aren't using a program that needs the antenna, the antenna is still sucking power away from your battery.
- Disable Push notifications, unless needed. Increasing your fetch interval will also increase battery life.
- Disable Bluetooth if you have no Bluetooth devices (duh). If you're like me and use Bluetooth in your car, I would just leave Bluetooth ON for convenience so you don't have to enable Bluetooth every time you go for a drive. More trouble than it's worth.
- Using App Store programs may HEAVILY decrease battery life. Games (especially 3D) are notorious for killing your battery. Programs that use location services also put a big strain on your battery.
- Use your Auto Brightness feature. The lower the brightness, the more battery life you will get.
- If you have no service at all, use Airplane mode. With no service, your phone will constantly look for a signal, which kills your battery very quickly. Airplane Mode will let you use your phone, but you won't be able to dial or receive calls.
- Make sure Auto-Lock is set @ 1 minute.


iPhone Charging

Initial Charge (a few theories out there, I felt this is the safest route to go)
#1 - Buy the iPhone 3G. Do not use the iPhone 3G.
#2 - Initially charge your iPhone for 3 hours. I've read conflicting statements about this. To be safe, don't use your phone before letting it charge for 3 hours. Also, use your wall charger (avoid the computer charger).
#3 - Now it's time to calibrate your battery indicator. Let the iPhone's battery fully drain. Keep the iPhone off for five hours once drained, then fully charge your battery. Allow the battery to rest in the fully charged state for two hours. You may use your iPhone during this time as long as the iPhone is plugged in.
#4 - Repeat step #3 a maximum of three times if you feel your battery indicator is inaccurate.

Everyday Charging
#1 - Charge your iPhone throughout the day when available. Try not to let your battery fully drain, but if it does drain, it won't damage your battery.
#2 - Use a wall charger or car charger w/ rated output 5V 1A. Computer chargers might not charge when the computer is in standby mode.
#3 - Fully charging your iPhone overnight is recommended, even if you have a lot of battery life remaining at the end of the day.
#4 - You cannot overcharge your iPhone. You don't need to disconnect the iPhone from the charger after it's done charging. Once fully charged, the iPhone will run strictly off of AC power and will not damage the battery.
#5 - 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.
#6 - If you ever need to store your iPhone for any reason, make sure your battery is stored @ roughly 50% and in a cool environment.
#7 - Use properly rated chargers. Using chargers that are not properly rated will have a huge impact on your battery's lifespan. Make sure your car charger has the same rating as the official Apple charger. The official Apple wall charger is rated as follows:

Input: 100 240V ~ 50/60 Hz 1.0A
Output: 5V 1A


#8 - Always charge your iPhone out of its case (assuming you can easily remove the case). Charging your iPhone inside your case will make the iPhone hotter, which is bad for the battery.

#9 - Charge your iPhone in a cool location. Charging your iPhone in a cool environment has a tremendous impact on your battery's lifespan. The colder the location you use to charge, the more charging cycles you can complete without your battery deteriorating. Avoid direct sunlight. DO NOT PUT PUT YOUR iPhone IN THE FREEZER!

This is what happens to hot batteries over time:
"The speed by which lithium-ion ages is governed by temperature and state-of-charge. Figure 1 illustrates the capacity loss as a function of these two parameters." - Battery University



More information can be found here:
http://www.crazygadgetguru.com/posts/2007/8/13/the-two-laws-of-iphone-battery-care.html
http://www.batteryuniversity.com/parttwo-34.htm
http://www.apple.com/batteries/maximizing-performance/
http://www.apple.com/batteries/
http://www.vsa.cape.com/~danh/ipod.htm#fiction



iPhone 3G Battery Tests:





Articles Testing The iPhone 3G's Battery Life
http://www.anandtech.com/gadgets/showdoc.aspx?i=3358&p=18
http://gizmodo.com/5025309/round-up-nine-iphone-3g-battery-life-test-results
http://forums.macrumors.com/showthread.php?t=520902
http://www.engadget.com/2008/07/16/iphone-3g-review-supplemental-battery-life-and-mobileme-tests/


Testing For Defective Batteries

As for defective batteries. First and foremost, charge from the wall. I tried charging my iPhone from my iMac and had a 20% charge the next morning. I'm not saying you can't successfuly charge from your computer, but to diagnose a problem, I would give the wall charger a shot.

#1 - Reset your iPhone. (To perform a soft reset, press and hold the iPhone’s Sleep/Wake button and the Home button for several seconds, or until you see the Apple logo on the screen)
#2 - Fully charge your battery.
#3 - Fully drain the battery.
#4 - Fully charge, again.
#5 - At this point, your battery indicator should be more accurate.
#6 - If your battery is still really weak, head to the Apple Store to potentially exchange your iPhone. (1 year warranty)
 
Last edited by a moderator:
Jul 16, 2008
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#2
Welcome to Eic. Excellent first post too! I'm sure a lot of members will respond to this as naturally everyone has their own opinoin(s). A lot of the information has been covered here but no one has put it all together in one posting. Nice work!
 

FlwrPwer

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Aug 7, 2008
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#3
I was told I didn't have to calibrate my battery by draining it. It was one of the first questions I asked.

Maybe I'll try this and see what happens.

Thanks! :)
 
Aug 13, 2008
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#4
I was told I didn't have to calibrate my battery by draining it. It was one of the first questions I asked.

Maybe I'll try this and see what happens.

Thanks! :)
One thing is for sure, you need to initially drain the battery to calibrate. Whoever told you otherwise is either mislead or confused.

Maybe they meant you shouldn't drain the battery for normal charging?
 

FlwrPwer

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Aug 7, 2008
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#5
One thing is for sure, you need to initially drain the battery to calibrate. Whoever told you otherwise is either mislead or confused.

Maybe they meant you shouldn't drain the battery for normal charging?
Nope, I specifically asked if I had to calibrate the battery. I have a powerbook, I know how the procedure goes. I was told not to. I think I will drain the battery today and fully charge it tonight and see if that helps.
 
Aug 13, 2008
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#11
I think people will always have differing opinoins on the issue but it certainly cannot hurt anything.
I agree, it can't hurt, especially if you haven't done it in a while. It's on the Apple support site, I'd say that's more trustworthy than an ignorant forum user / Apple employee.
 

sdge

New Member
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Jul 8, 2007
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#12
excellent post. Lots of information in a neat package.

Me personally would rather bring a charger with me everywhere then spend that much time concerned with the battery.

Either way, I use my iPhone for videos, 3rd party apps, Gps, and all sorts of battery draining stuff (my brightness is about 80%) but thing still lasts long enough for me to be out all day.

Still though, EXCELLENT post.
 

FlwrPwer

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Aug 7, 2008
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#13
I agree, it can't hurt, especially if you haven't done it in a while. It's on the Apple support site, I'd say that's more trustworthy than an ignorant forum user / Apple employee.
Hey, I'm all for trying it. The worst that'll happen is that nothing happens and its the same as before.

The best...my battery lasts a little longer.

Win, win situation to me :)
 
Aug 13, 2008
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#14
Hey, I'm all for trying it. The worst that'll happen is that nothing happens and its the same as before.

The best...my battery lasts a little longer.

Win, win situation to me :)
Well, calibrating your battery isn't going to add or decrease the lifetime of your battery. All it's going to do is make it the green battery indicator more accurate. It will prevent those "my battery was just at 60%, how is it already at 20%?" moments. Calibrate your iPhone every two months and your Powerbook every month. Laptops aren't used as much as phones, so their indicators need to be calibrated more often.
 
Jul 16, 2008
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#16
If I recall correctly I remember reading that the 3G phone is good for about 300 complete charge cycles. Mathematically for the majority of users that is less than 1 year of usage.
 
Aug 13, 2008
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#18
If I recall correctly I remember reading that the 3G phone is good for about 300 complete charge cycles. Mathematically for the majority of users that is less than 1 year of usage.
Charge Cycles
"A properly maintained iPhone battery is designed to retain up to 80% of its original capacity at 400 full charge and discharge cycles. You may choose to replace your battery when it no longer holds sufficient charge to meet your needs." -Apple

Apple says the iPhone battery can last 400 cycles before it goes to 80% capacity. I don't average a full cycle everyday, but that is different for everyone. I'm hoping my battery lasts a good two years before I notice "serious" charging deterioration.

One of the points of this thread is to increase the "recommended" 80%. If you use good charging habits, charge constantly, and in a cool location....that number could be closer to 85% or 90%. After two years, you could be at about 70% - 75%, which I could deal with. It will be time for a new iPhone anyway, as my contract will expire ;).
 
Jul 16, 2008
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#19
I have not noticed any major deterioration on my v1 phone. I'm hopeful that my smart charging practices will ensure that I receive at least the same battery life of my first gen iPhone. I know I'll want a new iPhone before my contract expires anyway; more like on iDay3.
 
Aug 13, 2008
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#20
I have not noticed any major deterioration on my v1 phone. I'm hopeful that my smart charging practices will ensure that I receive at least the same battery life of my first gen iPhone. I know I'll want a new iPhone before my contract expires anyway; more like on iDay3.
yes, if you're doing what you're supposed to, you should still have a pretty good battery. You should make it to iDay 3 easily, especially since the original iPhone doesn't have 3G to kill the battery. It's almost impossible to kill the original iPhone battery in a day.