Does leaving plugged in harm battery?

Paul22000 · Feb 28, 2010

I turn my phone on Airplane mode and unplug at night while I'm sleeping.

BUT! When at work and at home at other times, is it bad to leave it plugged in 100% of the time? (I.E. does it decrease total battery life over a few years to be constantly charging.)

Or is it better to unplug ASAP when it hits 100% and let it drop to 20-30% and recharge-unplug-recharge-unplug etc? (If so, how much of a difference would this make?)

And does it matter USB vs AC source? I know USB is half the amps, so this could have an effect too?

gsvnet · Feb 28, 2010

Honestly, the battery is going to deteriorate a bit either way over a year time span. It is probably best if you just replace the battery every year.

pjcforpres · Feb 28, 2010

Paul22000 said:
I turn my phone on Airplane mode and unplug at night while I'm sleeping.

BUT! When at work and at home at other times, is it bad to leave it plugged in 100% of the time? (I.E. does it decrease total battery life over a few years to be constantly charging.)

Or is it better to unplug ASAP when it hits 100% and let it drop to 20-30% and recharge-unplug-recharge-unplug etc? (If so, how much of a difference would this make?)

And does it matter USB vs AC source? I know USB is half the amps, so this could have an effect too?

Doesn't matter. All you need to really be worried about is that you leave it on the charger long enough to get a true 100% charge, and you don't always put it on when at 80%, try and run it down from time to time to 10% type thing.

If you leave it on the charger 24/7 for a year, it will have no real effect on the battery that a year of use wouldn't do, and you might actually come out ahead since battery life times are based on charge cycles... when on charger, as you are asking about, there would be virtually no charge cycles.

Paul22000 · Feb 28, 2010

pjcforpres said:
If you leave it on the charger 24/7 for a year, it will have no real effect on the battery that a year of use wouldn't do, and you might actually come out ahead since battery life times are based on charge cycles... when on charger, as you are asking about, there would be virtually no charge cycles.

Ooooh, interesting... Did not know that. I thought that leaving it charging was the worst case possible.

Amdathlonuk · Feb 28, 2010

But let's be honest.

How long do you think you'll keep the phone?

I've never had one more than a year...

Paul22000 · Feb 28, 2010

Amdathlonuk said:
But let's be honest.

How long do you think you'll keep the phone?

I've never had one more than a year...

Til the Nexus Two comes out bro

[Edit]: Well, my thinking is how BAD could this affect it. Like leaving it plugged in all the time = 50% battery capacity in 4 months type of thing. I guess that is not the case though eh?

uansari1 · Feb 28, 2010

Paul22000 said:
I turn my phone on Airplane mode and unplug at night while I'm sleeping.

BUT! When at work and at home at other times, is it bad to leave it plugged in 100% of the time? (I.E. does it decrease total battery life over a few years to be constantly charging.)

Or is it better to unplug ASAP when it hits 100% and let it drop to 20-30% and recharge-unplug-recharge-unplug etc? (If so, how much of a difference would this make?)

And does it matter USB vs AC source? I know USB is half the amps, so this could have an effect too?

To add to what pjcforpres said, I would suggest topping off the battery a couple times a day rather than always letting it run down to 20-30% (deep cycling) the battery. Deep cycling is worse for Li-ion batteries. It causes more heat for longer periods of time when you do charge. I would only discharge completely once every few months to keep the battery calibrated.

My personal habit is to top off frequently. If I'm at home, I'll let it charge to a true 100%, like pjc said, then take it off the charger and leave it off till it hits 75-80% and top it off again.

creepinshadow · Feb 28, 2010

i can add to this discussion what i've learned about lithium-ion batterys

having it plugged in, while it is being taxed heavily (playing games) and already at 100% is a bad idea, then i discharges and recharges all over the time.
When it isn't full and you plug it in to top it off it shouldn't really do any harm, as long as you disconnect it when it's at 100%.

Emptying it completely also lowers overall capacity, 10% is a good threshold when to charge it.

When leaving it off to store it for a while, store it with around 70-75% in the battery. Storing it fully charged also lets capacity down.

Paul22000 · Feb 28, 2010

creepinshadow said:
i

Emptying it completely also lowers overall capacity, 10% is a good threshold when to charge it.

I thought you WANTED to do this? I've heard calibrating it is running it until it turns OFF?

uansari1 · Feb 28, 2010

Paul22000 said:
I thought you WANTED to do this? I've heard calibrating it is running it until it turns OFF?

I respectfully disagree with creepinshadow's suggestions. I've read up on lithium ion batteries considerably in the last few years. 10% is not a good threshold to always charge your battery from... that's deep cycling and was great for nickel metal hydride, but isn't good for lithium ion. That said, there's no way for it not to get that low from time to time if you're away from your charger for extended periods and I'm sure it's not going to destroy your battery as fast as one might think.

As for storage, the I charge (or discharge) mine to 40-45% then pop it into the fridge for storage. Read that in a long article explaining how to treat li-ion batteries.

Like you said though, a full discharge for calibration is running it till it turns off then plugging it in while keeping it off until an hour or so after the light turns green.

jerhoyet · Feb 28, 2010

I've heard many people say that leaving any device that has a battery plugged in won't harm it as long as you're consistant with the charge cycles. Like only plug in your phone when the battery life is >15% and charge it to 100% before unplugging it.

I get into trouble there, because (for instance) say I'm going to be going into the mall for a while and my battery is at 30% and it's going to take me 30 minutes to get the mall (I live in Northern Virginia, traffic is a *****, haha). I'll hook up my phone while I'm in the car just to have extra battery life while I'm away from a charger.

thisguy10 · Feb 28, 2010

good question, i wanted to know the exact same thing so good to see someone else ask. got the answers i needed.

uansari1 · Feb 28, 2010

Look guys... the reality is that this discussion is really just academic. Take my recommendations, for example. It would be ideal if everyone could do what the study I read suggested, but it's not practicable to always top off the battery and not deep cycle the battery frequently. That being said, I'm sure the difference in battery life wouldn't be apparent for a very long time. I can't imagine phone and battery manufacturers haven't thought about this. So...while I've posted my "recommendations" based on that study... just enjoy your phones.

scottypimpin636 · Feb 28, 2010

A new battery cost <$50 i'm sure... If you left your phone plugged in over night, every night for a year it probably won't hold a charge better than someone that unplugs in once it reaches 100%..

I personally would rather not deal with always worrying about over charging it and IF i still had the phone when the battery needs to be replaced, just replace it.

In the past 16 months i've had the Touch Pro, Palm Treo Pro, BB Bold & now the N1.. so i never have a phone long enough to even care lol.

Paul22000 · Feb 28, 2010

I guess that's true. We can always replace the battery, unlike the Fruit people!

But I was just worried that the damage happened quickly. But I guess it's 9-12 months before seeing any real effects anyway.

uansari1 · Feb 28, 2010

scottypimpin636 said:
A new battery cost <$50 i'm sure... If you left your phone plugged in over night, every night for a year it probably won't hold a charge better than someone that unplugs in once it reaches 100%..

I personally would rather not deal with always worrying about over charging it and IF i still had the phone when the battery needs to be replaced, just replace it.

In the past 16 months i've had the Touch Pro, Palm Treo Pro, BB Bold & now the N1.. so i never have a phone long enough to even care lol.

Actually, it's only $25 from Google.

Paul22000 · Feb 28, 2010

uansari1 said:
Actually, it's only $25 from Google.

Link?

I don't see an accessories page at www.google.com/phone

[Edit]: lol nevermind, you have to click "Get your phone" to get accessories haha

uansari1 · Feb 28, 2010

Paul22000 said:
Link?

I don't see an accessories page at www.google.com/phone

Lol... click on the link you posted, click "Get Your Phone" and it's listed right below the Dock!

Paul22000 · Feb 28, 2010

uansari1 said:
Lol... click on the link you posted, click "Get Your Phone" and it's listed right below the Dock!

Yeah just saw that. Kind of silly to put it there since people looking for accessories already HAVE a phone. Silly Google

Paul22000 · Feb 28, 2010

Oh, so by the way, this page brings up a good point:

http://www.google.com/support/android/bin/answer.py?hl=en&answer=175535

Charges at 480mA when installed in Nexus One phone connected to USB, at 980mA when installed in phone connected to charger

Is there any difference in charging from USB vs AC adapter in terms of how it affects overall battery life?

Does leaving plugged in harm battery?

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