Fix iPhone 3GS Endless Reboot or Sudden Shut Down After Replacing New Battery

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Got your iPhone 3GS battery replaced and now it keeps booting every few minutes or so? Try this fix.

This issue seems to be caused by the battery or how the iOS handles power management of the iPhone. Sometimes after a battery is replaced, when the power percentage drops to 30~50% the iPhone will turn off. After trying to turn it back on again it goes into an endless cycle of showing the Low-Battery screen. It then attempts to start with the Apple logo, then restarting all over again in a minute or two.
The folks at reported that:
This could be a mismatch between the presumed or old battery charge curve and the new battery is likely. Mostly the iOS installed thinks that the battery still has 30~50% of power left when in fact it empty, a lot of this is because lithium cells have an exceptionally flat discharge curve and thus estimating the energy left is not always practical without keeping track of the mAh consumed.

Now here’s what you can try:

1. Put the iPhone 3GS into DFU mode (black screen)

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a. Hold down the power button for 4 seconds
b. Hold down the home button for 10 seconds
c. Release the power button
d. Wait 15 seconds
e. Release the home button

2. Charge for 30 minutes.

3. Exit from DFU mode.

a. Press the home + power button for 15 seconds
b. Release both buttons
c. Press the home button for 3 seconds

Your iPhone should now be booting into normal mode and you should be able to continue charging normally once more.


Fix iPhone 3GS Endless Reboot or Sudden Shut Down After Replacing New Battery was last modified: March 11th, 2013 by Joe Wang

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