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battery- replaceable under warranty?


Distinguished Member
I have a an iphone 4 - i got it the day after the release date so it is still within it's 1 year warranty.

The battery goes from 100% to 16% in one day with very, very light use.

I have 3g off and have turned off apps running in the background.

Anything I can do? or is Apple likely to say i haven't been charging it well?
I am very anal about charging and always wait till its below 5 % and then do a full charge.


Distinguished Member
As Apple use Lithium Ion and LiPo batterys, fully discharging them is not required, and if taken too far, will actually kill them ! If the cell voltage drops below a critical point, they will not accept a re-charge. The phone will have a built in circuit to prevent over-discharge, so you are unlikely to have caused any damaged by running the battery to less than 5% The guidance to fully discharge refers to NiCad & NiMH batteries of older and cheaper phones.

Li-ion and LiPo should be good for at least 500 charge cycles, so at less than a year old, I cannot see a reason why Apple would not treat this as a faulty battery.


Well-known Member
Like noiseboy72 there's really no need to be anal about charging with these batteries, LiIon actually prefers to be kept around 50% charged. What they don't like however is very high (>45C) or very low temperatures (<5C). Eg leaving the phone in a car under the sun will definitely affect their performance.

I'm sure Apple will sort it out for you. If you go to their stores they can even run diagnostics to figure out where the charge is going.

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