Optimizing iPhone battery life: Between charges and before replacement

FYI. An excellent iPhone battery care article by iPhoneAtlas.com:

Optimizing iPhone battery life: Between charges and before replacement

http://www.iphoneatlas.com/2007/07/09/optimizing-iphone-battery-life-between-cha rges-and-before-replacement/

iPhone 8GB, Core2Duo MacBook, CoreDuo 20" iMac, iMac G4, iMac G3, 3 iPods, Mac OS X (10.4.10)

Posted on Jul 9, 2007 4:20 PM

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14 replies

Jul 9, 2007 4:29 PM in response to Dizzy D

The information on that web site is incorrect. In the very first paragraph he writes: ...meaning that after a certain number of charge cycles (approximately 400, according to Apple) you will need send your phone to Apple and pay $86....to replace the battery.

This simply isn't true. The battery does not die after 400 charge cycles it is simply reduced to 80% of it's original charge capacity. See this Apple iPhone support page.

Based on this I would be highly dubious about anything you read about iPhone on that web site.

Jul 9, 2007 4:39 PM in response to Michael Allbritton

OK, I agree that is a completely false statement. The rest of the article is pretty good.

If you assume a linear decrease in battery charge for each full cycle (which it really isn't, but much easier to model in a spreadsheet). Then 80% of original charge after 400 full cycles is approximately 0.8% loss in battery charge per full charge cycle (again this is a simplification, stay with me). This means that after 400 cycles, you are at approximately 80% of your original total charge level. As stated by Apple.

So, extrapolating that out to EOL (end of life) which Apple assumes to be 50% battery charge, it would take approximately 1,000 full charge cycles for your battery to be EOL (according to Apple). It would actually be slightly less than that since it won't be a linear function.

For me, that's 2 to 4 years of use depending on whether or not I continue using the iPhone as much as I have this first full week.

Jul 9, 2007 4:47 PM in response to Michael Allbritton

"The information on that web site is incorrect. In the very first paragraph he writes: ...meaning that after a certain number of charge cycles (approximately 400, according to Apple) you will need send your phone to Apple and pay $86....to replace the battery."

Not to mention, 1 charge cycle means a FULL charge, from dead. If you charge with 50% strength remaining, it would only count as 1/2 a cycle.

Articles like that are why people are freaking out over nothing.

Jul 9, 2007 4:51 PM in response to MacFishy

Yeah, all this hysteria is over nothing. The geek-a-trons were freaking out about the iPod battery not being user-replaceable when it first came out and Apple has sold over 100 million of those. I don't think the average consumer really cares that they can't replace the battery themselves.

I generally get a good 3 years out of my MacBook Pro (formerly known as PowerBook) batteries before I have to buy a new one. People are getting all worked up over nothing.

Jul 9, 2007 5:48 PM in response to Dizzy D

I called Apple tech support because I had a separate battery issue.

The tech support agent asked me when / how often I charge the phone. I told her that I charge it around 40%, or even when I have more. Usually I do it nightly.

She gave me a big lecture on how I should ONLY charge it when it reaches below 20% or else my battery will wear out faster.

I think there's something fishy about what she said, and what should be the "best practice" in charging these iPhones?

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Optimizing iPhone battery life: Between charges and before replacement

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