To maintain battery health w/iPhone is it best to leave plugged in or not?

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To maintain battery health w/iPhone is it best to leave plugged in or not?

So I know for best battery life one should power cycle monthly, but is it better to leave the unit NOT plugged in and wait until night (or every other night) for battery health and maintenance or would it be better to plug it in when I get home early, in my car adapter, or even at work when I'm next to a computer?

I'm not very familiar with batteries anymore and wasn't sure which route is better with Apple's technology. I suspect the difference isn't too big either way since I'm avoiding (at most) a few hours of standby by plugging at work comp/car/home/etc and that the overnight plug in means more, but I figured I'd ask some people who were more likely to know than I.

IPhone 3, iPhone 3G, 2.33GHz Core 2 Duo Mac Book Pro 17", iOS 4

Posted on Sep 6, 2010 6:07 AM

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Answer 1

Injector

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77 points

Sep 6, 2010 6:16 AM in response to prateeko

The fact remains that charging a battery reduces its life, you can't escape that. The less charging you do the better.....but obviously you need to use your phone SO, charge it when it needs charging and top-up via your MAC/PC if you feel you're going to run out of juice later. Continually charging the battery when you don't need to, ie constantly keeping it topped-up is a bad idea with regard to battery longevity. The bottom line though is just use it.

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Answer 2

wjosten

Level 10

95,369 points

Sep 6, 2010 6:19 AM in response to prateeko

The iphone has a LI battery, it has no memory effect, you can charge anytime you want. So, plug it it whenever you want.

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Answer 3

isoToxin

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59 points

Sep 6, 2010 7:13 AM in response to prateeko

Doing a complete cycle once a month is more for ensuring that it's calibrated properly, rather than improving the battery health. Li-ion batteries are healthier when you do partial charges only, not full charges.

As for leaving it plugged in or how often you should charge, with li-ion batteries you don't really need to worry about it. The battery has an overcharge protection circuit, so it's impossible to damage it by leaving the phone connected to the wall outlet. As the earlier poster has said, there is also no memory effect, so no advantage to doing full charge cycles (and in fact this is discouraged with this battery technology except when it needs re-calibrating so that the "battery remaining" display is accurate).

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Answer 4

prateeko Author

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Sep 6, 2010 10:40 AM in response to Injector

So I guess I'm confused by injectors comments versus the other replies. Obviously battery degrades but is it charging that lessens the battery life? Because then leaving it plugged in isn't a good idea but the other replies indicate there is a built in overcharge protector and thus it's okay to leave it plugged in...

Thus my original question, to leave plugged in during the day/care/overnight, drain to completion or drain during the day and charge overnight? Neither way is worse for me so I figure it can't hurt to establish good habits early.

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Answer 5

richard-

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Sep 6, 2010 10:52 AM in response to prateeko

I was looking for the answer to this question too.. because im using my iphone 4 as a sat nav and it uses the battery lots

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Answer 6

wjosten

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95,369 points

Sep 6, 2010 11:39 AM in response to richard-

Quoted directly from Apple:

You can also recharge a lithium-ion polymer battery whenever convenient, without the full charge or discharge cycle.

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Answer 7

Sep 6, 2010 11:46 AM in response to prateeko

Like mentioned most phones including ours have memory. Hence it knows when it's fully charged, dead, etc. Anyone who's owned a laptop knows if you leave it plugged in all the time eventually it will cause damage. Of course it's impossible to leave a phone on a cord all the time. However for those who constantly charge their phone will have long term damage after some time eventually. This is my first iPhone and I can honestly say this phone has the best battery life of any PDA I've owned since my first in 2005 (Palm Treo 700wx).

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Answer 8

Injector

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77 points

Sep 6, 2010 12:15 PM in response to prateeko

Batteries have a finite lifespan and the more charging cycles they have under their belts, the quicker they will deteriorate. You cannot overcharge the battery, you can charge and charge to your heart's content. So nothing you are advocating will damage your battery....however the less charging you do, the better! It's a no-win situation really, just use the thing.

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Answer 9

Sep 6, 2010 12:52 PM in response to VibrantRedGT

VibrantRedGT wrote:
Like mentioned most phones including ours have memory. Hence it knows when it's fully charged, dead, etc. Anyone who's owned a laptop knows if you leave it plugged in all the time eventually it will cause damage. Of course it's impossible to leave a phone on a cord all the time. However for those who constantly charge their phone will have long term damage after some time eventually.

So you disagree completely with Apple about Apple's batteries?

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Answer 10

prateeko Author

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Sep 6, 2010 2:05 PM in response to Injector

I disagree about the memory effect post, and it seems charge cycles are additive ( http://www.apple.com/batteries/ ). That is, drain 25% per day and recharge it is equal to one day where you exhaust the battery. And since it seems like there is no penalty for recharging, it would make more sense for me (on days where I'm next to a computer/outlet/car adapter/sleeping) to plug it in since the __% I'd lose then would be handled by the power plug and not the iPhone. I'm sure it's minuscule, but I have chargers/adapters all over the place from various iPods, but I've avoided plugging ok because I thought it was supposed to be bad to always charge/better to let it drain some.

I mean, from the link and what you guys said, what I'm thinking of doing is better than always draining/not plugging in when I'm sitting around, right?

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