Battery Loss Overnight

[BigButa]

One thing that seems to need clarification here

For those of you saying that your battery is still at 99% in the morning when you wake up: you haven't really lost just 1% battery. Haven't you noticed that when you charge up to 100%, it takes much longer to go to 99% when using it than it does when going from say, 50% to 49%?
The same concept is at work with your car when you fill up the gas tank. The needle seems to stay above the Full mark for a long time, and you may get 50 miles before it dips below that mark. However, once it dips below that mark it never stays at any one point as long as it did when it was above the Full mark, and your gas seems to get used up much more quickly thereafter.

In essence, you should really consider your iPad battery power display and car's fuel gauge to go up to not 100%, but about 105%. Sorry to say, but when you wake up in the morning and your iPad says it has 98% battery remaining, you probably actually drained about 7% overnight.

I don't know why remaining battery power / fuel gauges work like this, but they do.

 

[Stealthipad]

Should let us know if yours is wifi-only or 4g equipped (with a data plan) and what's turned on, whats turned off, etc.

I am WIFi but have LTE. The LTE is off and I have never had it turn it's self on that I know about. I seldom even close apps and just close the cover. If it says 87% remaining when I go to bed, it has 87% in the morning or even next afternoon. I do have mail turned off as i get it on my 4S and do not do socail networking on either device.

10% is a lot to not be accounted for.

 

[andrewfee]

iOS 5.1 still hasn't fixed all the outstanding battery life issues yet.

Unfortunately to test for this, you probably need to purchase an app such as Activity Monitor Touch. (it's on sale right now, but was free some time last year)

Turn on Airplane mode, disconnect any cables from the iPad (charge/sync etc.) load up an app that graphs CPU usage, and leave it alone for a minute. You should notice CPU usage dropping below 5%.

If it doesn't, I would try quitting all open apps, restarting the iPad (leaving Airplane mode enabled) and trying again.

You may need to restart the iPad twice for CPU usage to drop to 1% as it should do in this situation. (note: you do have to leave it for a minute or two to "settle")

This is my iPad after restarting it twice:

(graph scale doesn't appear to be accurate at 2048×1536, this is 1%)


With my iPad 2 and iOS 5.0, CPU usage would go as high as 25% when idle, this is after leaving it alone for several minutes, so it wasn't fetching mail or anything like that.

In the iOS 5.1 beta, this dropped to about 15%, and with the iOS 5.1 release, it reached about 10%.

My new iPad also seems to be hitting 10% idle CPU usage after a few days without restarting. I have to do this once or maybe twice a week to stop battery life from draining too quickly.

Note: it will almost never get back down to 1% idle after you've used the device for a while, typically 3–5%.

I wish there was a way to find out specifically which processes were causing this, but there doesn't appear to be a way to get any more detailed information than overall CPU usage. (I've looked at several apps and they all appear to only give you an overall graph)

 

[Diversion]

I am WIFi but have LTE. The LTE is off and I have never had it turn it's self on that I know about. I seldom even close apps and just close the cover. If it says 87% remaining when I go to bed, it has 87% in the morning or even next afternoon. I do have mail turned off as i get it on my 4S and do not do socail networking on either device.

10% is a lot to not be accounted for.

I agree.. and after speaking to a Apple "engineer" today; he tells me 10% loss overnight is not right, but to give it a few days for the battery to cycle again and calibrate. I'll report back with my findings.

 

[andrewfee]

I agree.. and after speaking to a Apple "engineer" today; he tells me 10% loss overnight is not right, but to give it a few days for the battery to cycle again and calibrate. I'll report back with my findings.

I guarantee it's high idle CPU usage causing this—a software issue, not a hardware one.

 

[Stealthipad]

I agree.. and after speaking to a Apple "engineer" today; he tells me 10% loss overnight is not right, but to give it a few days for the battery to cycle again and calibrate. I'll report back with my findings.

Let us all know how it works out.

 

[Diversion]

I guarantee it's high idle CPU usage causing this—a software issue, not a hardware one.

You could very well be right - i'm too cheap to buy a CPU monitor app though

 

[Diversion]

Update!

I went ahead and just turned airplane mode on last night before going to sleep.. I was at 32%.. This morning, about 7ish hours later (I never get 8 hours of sleep, stay up way too late all the time!) I was still at 32%..

Seems like the radios (probably the cellular) eat up a decent amount of juice even when sitting idle.

 

[andrewfee]

Update!

I went ahead and just turned airplane mode on last night before going to sleep.. I was at 32%.. This morning, about 7ish hours later (I never get 8 hours of sleep, stay up way too late all the time!) I was still at 32%..

Seems like the radios (probably the cellular) eat up a decent amount of juice even when sitting idle.

I guess it couldn't have been idle CPU usage in your case then.

When did you get your iPad? Had you made any big changes to it the day before?

Is it possible that it spent a lot of time uploading a new backup to iCloud?

 

[phpmaven]

No iCloud, no apps running in the background, mail is on fetch, location services off, brightness is dimmed. I feel like I'm doing everything to conserve battery and it's still getting F'd. Is a faulty battery a possibility? I know this new iPad uses battery but damn, it shouldn't be this much.

Here's a crazy thought, plug it in during the night. I know it's a radical idea, but I thought you might be getting desperate.