Comments on: iPhone battery myth clarified: 80% power left after 400 charges

By: Eytan

Eytan — Wed, 11 Jul 2007 22:56:05 +0000

Check out this site for proper battery care and feeding:
http://www.apple.com/batteries/

By: Vincent Nguyen

Vincent Nguyen — Wed, 11 Jul 2007 16:28:05 +0000

Ken, first of all, many thanks for the detailed explanation. I’m scheduled to go in to get my second iPhone replaced. For some reason, my battery is not holding charge.

http://www.myitablet.com/talk/11_571_0.html

By: Chris Davies

Chris Davies — Wed, 11 Jul 2007 15:06:53 +0000

Thanks Ken!

By: Ken

Ken — Wed, 11 Jul 2007 14:51:25 +0000

Chris, I disagree that iPhone (and iPod) batteries should be deep cycled. That is a common misconception. I wouldn’t call myself a “battery expert” but I’ve done a fair amount of research in this area. My belief is that the iPhone should be kept docked when possible, if your desire is to maximize the lifetime of the battery.

Lithium ion polymer batteries (which are the type used in the iPhone) do *not* suffer from the memory-effect phenomenon that NiCad and NiMH batteries do. The loss of capacity in LiIon batteries occurs because the metals in the cells oxidize during discharge and recharge. This is why Apple and battery manufacturers rate the lifetime of the battery by the number of full charge cycles.

Some people get confused because manufacturers sometimes recommend doing a full discharge-charge cycle to “calibrate” a lithium ion battery. This isn’t “reconditioning” the battery in any way; it’s only done so that a device can properly measure the current capacity of the battery.

It is likely that keeping the iPhone docked will increase the battery life slightly, because while docked, it is probably drawing operational power from the dock connection and not the battery. Since the battery is not discharging and recharging as much, that should increase its life.

It’s worth noting that one of the best things you can do is keep your iPhone out of excessive heat (like, inside a sunlit parked car in the summer). Heat is an absolute killer when it comes to batteries.

By: Chris Davies

Chris Davies — Wed, 11 Jul 2007 13:32:02 +0000

As far as I'm aware (and if there's a battery expert out there, please correct me if need be!) it's better to wait until it needs charging, charge it fully and then remove it from the dock. Partial charge cycles and leaving it sat on charge continuously could, I think, reduce the capacity as a whole. Not to the same extent as with older NiMH cells, but still some effect.

Of course, it's also more environmentally friendly to unplug the charger when you're not using it - even when the phone is fully topped up and just sitting there, the wall-wart still uses some energy.

[quote comment="5370"]Is it best for the iphone battery, when the iphone is not being used, to keep it charged in the dock? or to wait until it needs recharged?

or does it not matter?[/quote]

By: Tony

Tony — Wed, 11 Jul 2007 12:26:34 +0000

Is it best for the iphone battery, when the iphone is not being used, to keep it charged in the dock? or to wait until it needs recharged?

or does it not matter?