Sixth iteration of Apple iPhone, announced on September 12, 2012. Repair of this device is similar to the previous models, requiring screwdrivers and prying tools. Available as GSM or CDMA / 16, 32, or 64 GB / Black or White.

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Why is battery calibration important?

I wonder not just why battery calibration is important, but also what are the (temporary or permanent) effects of doing it correctly or incorrectly on my new iPhone 5 battery.

There are a couple of good answers to questions about why battery life is short, but I would like a concise explanation of all aspects.

ifixit says "for optimal performance... drain battery below 10%, then charge UNINTERRUPTED to 100%.

My battery started at 40% and has dropped to 14% overnight. How can I drive it lower, so I can complete the calibration ASAP? (I went to settings/general/usage/battery usage, activated settings like bluetooth and personal hotspot, are there other ways I could use battery more quickly?)


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It's NOT important.

The calibration simply gives you slightly better idea of how much power is left. The battery performance profile is affected by temperature, so it cannot predict remaining power if there is a dramatic change in temperature, especially when it is cooled down. Also the material of the battery may have performed less than Apple imagined, so the predicted model departed even further form the actual performance, which is why they recalled certain units. Unless you replace the battery, there is not much you can do to restore performance.

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Thanks, TC, but I evidently was not clear. This is a new battery, first-time calibration. Please read the whole question.

If calibration is not important, why is it recommended? I want to start off on the right foot with my new battery.


I've never calibrated my batteries since the Samsung Galaxy S3 was released (that was March 13th 2013). Never had issues that ever pointed to calibrating batteries. They either work fine or their faulty.

I think it's just a waste of time of doing so.


Then it's the problem with the battery, or the system is still using old data on your new battery.


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John Lozier will be eternally grateful.
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