I recently put some iPads up around my office building as conferance room markers. They're plugged in to USB outlets, and seem to be charging fine. The screen stays on all the time, running Eventboard Pro.

The problem is that in order to keep the battery from running down while plugged in, I adjust the screen brightness to around 75%. But, whenever I come back to them later in the day, they brightness slider is back at 100%, causing the battery to drain. Usually when I arrive in the morning I have to go around the building, manually turning on and lowering the brightness. Autobrightness is turned off on all of them, and I'm pretty sure the outlets are fine, as it charges during the day with lowered brightness.

Is this auto-adjustment in brightness a known issue, or is there some hidden setting I'm missing? The iPads are all updated to the most recent iOS as of April 1st, and it's a mix of iPad 2s and New iPads.

If I need to provide any other information, I'll be happy to do so. Thanks for looking!

  • That is really strange. And all of them are displaying this behavior? I suppose you don't have any iOS 5 devices, that you could test? Apr 1, 2013 at 14:22
  • I don't have any iOS 5 devices, but I have tried rotating them between outlets, and while all of them increase the brightness, only certain iPads lose battery charge instead of holding steady. Could it be a couple of bad batteries?
    – KrispyMart
    Apr 1, 2013 at 14:47
  • Yes, it is possible the battery could be to blame (but, to be honest, I might be a little surprised). I would expect a pretty close use/age correlation to loss of charge, though, if that was the case. You are using the actual iPad 10 watt charger, and not the small iPhone charger, correct? I would be very surprised if rotating outlets would help at all. I'm testing my iPad (3) right now to see if it will drain at 100%. Also may check to see if it does the 75% to 100% change latter. Apr 1, 2013 at 15:11
  • It's not using a charger, it's just a usb cord directly plugged into a usb outlet. I can find the model of outlet, if you like. I'm assuming the battery drops because of the brightness change, as the charge holds just fine at lower brightness levels.
    – KrispyMart
    Apr 1, 2013 at 15:19
  • That makes sense now (I missed the original mention about USB outlets in your question). Chances are the USB outlets aren't giving quite as much power as the power supply the iPad is sold with does. That would explain the battery loss. So we are obviously back to needing the brightness to stay where we want to. I went ahead and moved my brightness to ~75% and am leaving the iPad unlocked. I'm curious if I can replicate the problem. Apr 1, 2013 at 15:25

1 Answer 1


First, to directly answer your question, no, there is no hidden setting that is causing your brightness to increase without your input. The only to settings related to brightness as of iOS 6 is Auto-Brightness (which you have disabled), and the brightness slider. As far as I'm concerned, it must be a bug.

So it looks like you have a few sub-par options.

  1. USB outlets are really nice, but in the long run, they may not be a good solution for you. Even though the original power supply bricks that come with iPad, stick out of the wall, and can be in the way, they do supply enough energy to keep the iPad charged, and even charging despite high battery consumption at the same time.

  2. Bring one home to see if you can replicate the problem with original charging apparatus. If this is the case, you may consider scheduling an appointment, and taking it to one of Apple's Genius bars. Perhaps they are aware of a bug or will have an idea as to what is going on.

One side note, I have seen extremely strange behavior when an iOS device is given "bad" power. If the USB outlets are questionable quality, there is a far-out chance this is causing it. That said, most of the behavior I have seen from "bad" power comes from touch screen activity, and this would mean that each device was used in between times that you checked on it.

Either way, my recommendation would be to use the included chargers with your iPad if that is at all possible.

  • 1
    The brightness was being adjusted by the Eventboard Pro online dashboard, turns out there was a setting on there that bumped it to the preset level every hour. Thanks for all your help, replacing one of the outlets DID allow the iPad to run at full brightness, so clearly not all usb outlets are made equal.
    – KrispyMart
    Apr 10, 2013 at 13:48
  • That is great. Thank you for coming back to wrap this up. I'm glad you found a good solution. I will have to remember that some apps do that. I know they can control brightness (i.e. Amazon's Kindle app), but didn't think of that part of resetting brightness. Apr 10, 2013 at 13:54

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