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Battery dropped ~20% while off; normal?

D

divergirl

macrumors regular
Original poster
Oct 30, 2012
118
24
I left my charger at a friend's house yesterday and won't be able to get it back till tomorrow due to inclimate weather, so I thought I would just turn the iPhone off and turn it on twice a day just to check my texts. But when I shut the phone off this morning it was at 35% battery life, and when I turned it back on this evening it was at 16% battery life!! I guess I don't know much about lithium ion batteries but I just assumed it wouldn't drain at all in 12 hours if turned off.

I haven't had major issues with the battery during actual usage (I get about 5 hours usage time, which I figured is pretty typical for a 20-month-old phone) but now I'm wondering if I should take it in to Apple for diagnostics while I still have two-and-a-half more months of AppleCare+ remaining. Has anyone else experienced this, and should I be concerned? Or is this totally normal?

As an aside, I can't believe I have to wait another 24 hours to get my charger back... I hopped on iMore last night and bought a backup charger so hopefully I'll never have to go through this again! If only we hadn't had a terrible snowstorm today...

Edit: Oops, I just realized maybe I should have posted this in the "iPhone Tips, Help and Troubleshooting" forum. My apologies! Mods, feel free to move this post if it is inappropriate for the general iPhone forum.
 
Did you leave it in cold or hot? Because if it's somewhere cold the battery dies. If it's some where hot well then you can do pemint damage to the battery.
 
The Doctor11 said:
Did you leave it in cold or hot? Because if it's somewhere cold the battery dies. If it's some where hot well then you can do pemint damage to the battery.
Click to expand...

I can't speak for the entire life of the battery as I bought the phone secondhand, but it hasn't been exposed to any adverse conditions since I've had it. Today (when the battery dropped 20%) it didn't even leave the house and spent the entire day (turned off) laying facedown on my counter, which I reckon was about 68 degrees, if our thermostat is accurate.
 
divergirl said:
I can't speak for the entire life of the battery as I bought the phone secondhand, but it hasn't been exposed to any adverse conditions since I've had it. Today (when the battery dropped 20%) it didn't even leave the house and spent the entire day (turned off) laying facedown on my counter, which I reckon was about 68 degrees, if our thermostat is accurate.
Click to expand...

Well then it's not because of temp. And I've never left my phone like that for a long time so I'm not sure what normal would be. If it wasn't on wifi it would be worse then if it was. But really that's it. If the battery is fine when you use it normally then I see no reason to get it replaced. What kind of phone is it?
 
The Doctor11 said:
Well then it's not because of temp. And I've never left my phone like that for a long time so I'm not sure what normal would be. If it wasn't on wifi it would be worse then if it was. But really that's it. If the battery is fine when you use it normally then I see no reason to get it replaced. What kind of phone is it?
Click to expand...

It's an iPhone 4S. It's a little over 20 months old and I've had it around two weeks now. I know it's an older model but it's my first iDevice so everything is new and wonderful right now. I'm really loving iOS 7! :D But since it's my first, I've kind of been treating it like a little baby hence why I'm like "Oh no something is wrong what shall I do! :eek:" You do make a good point though... since the battery is fine under normal usage maybe it's not worth getting checked out. It just seemed very strange to me.
 
jav6454 said:
Although not unheard off if the iPhone is old. Which OP hasn't really explained.

Edit - Oh wait, he says its a 20-month old iPhone. 20% sounds reasonable due to battery wear n tear.
Click to expand...

My 3 and a half year old blackberry battery would lose maybe 2% while the phone is off. 20% does sound like a lot.
 
divergirl said:
It's an iPhone 4S. It's a little over 20 months old and I've had it around two weeks now. I know it's an older model but it's my first iDevice so everything is new and wonderful right now. I'm really loving iOS 7! :D But since it's my first, I've kind of been treating it like a little baby hence why I'm like "Oh no something is wrong what shall I do! :eek:" You do make a good point though... since the battery is fine under normal usage maybe it's not worth getting checked out. It just seemed very strange to me.
Click to expand...
Well apple claims the 4s stand by battery life to be 200 hours. If you do the math and find out how much the battery should drop in your time that would be cool. Now I sorta wondering what apple thinks it should drop. Of course that would be with a brand new battery but still worth finding out.
 
divergirl said:
I left my charger at a friend's house yesterday and won't be able to get it back till tomorrow due to inclimate weather, so I thought I would just turn the iPhone off and turn it on twice a day just to check my texts. But when I shut the phone off this morning it was at 35% battery life, and when I turned it back on this evening it was at 16% battery life!! I guess I don't know much about lithium ion batteries but I just assumed it wouldn't drain at all in 12 hours if turned off.

I haven't had major issues with the battery during actual usage (I get about 5 hours usage time, which I figured is pretty typical for a 20-month-old phone) but now I'm wondering if I should take it in to Apple for diagnostics while I still have two-and-a-half more months of AppleCare+ remaining. Has anyone else experienced this, and should I be concerned? Or is this totally normal?

As an aside, I can't believe I have to wait another 24 hours to get my charger back... I hopped on iMore last night and bought a backup charger so hopefully I'll never have to go through this again! If only we hadn't had a terrible snowstorm today...

Edit: Oops, I just realized maybe I should have posted this in the "iPhone Tips, Help and Troubleshooting" forum. My apologies! Mods, feel free to move this post if it is inappropriate for the general iPhone forum.
Click to expand...

Bring it into Apple and they will run a check. It sounds like your battery is bad and performing way under 80% of capacity. It will only get worse if you don't take care of it now. The replacement is $80.
 
Have you been able to replicate the issue? It could also be that the calibration was off that day before shutting off; or right after you powered it back on. My phone's battery calibration seems to reset itself slightly whenever I do a power on/ power off.
 
Power off and then on in only 12 hours isn't a wise choice.
The power on process is quite "stressful", and it probably drains the battery more than a 12 hours aero mode enabled.

Btw 20% seems to be a little too much! and your battery could be ruined (cold weather doesn't help).
In 12 hrs an iPhone with aero mode enabled should drop not more than 4-5%.
 
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