iPad is hot even when idle. Is the battery dying?

July 13, 2020 4:41 AM

I have a six year old iPad. Recently it is hot to the touch even when it is essentially idle (shut down, allowed to cool, restarted but no apps opened). Does this mean that the battery is starting to fail, or could there be some other cause?
posted by Grinder to Computers & Internet (13 answers total)

In general, no - a battery that's reached its number of useful charge/discharge cycles won't tend to heat up when it's in use. It's possible that iOS or another is trying to do something in the background and failing but refusing to give up. (I've had similar problems in the past with other devices, for example, trying to download updates over spotty wifi.) If you have a thermal camera or IR thermometer, you might be able to tell if it's the battery or another component - starting from a cold device, turn it on and take several readings across the back of it. The iPad battery is basically the size of the entire device, so a hot battery would show up as a uniform temperature increase. Hot spots would likely indicate that it's working hard on something.

If you notice the device getting hot even when turned off and unplugged, or if it starts bulging, then you have an immediate problem. These are signs of an incipient battery fire, and it will get out of control quickly if you're not careful. Make sure it's turned off, and then throw it in your sink and start running cold water on it. You will need to keep it cooled to prevent a thermal runaway which will start (and feed) the fire.
posted by backseatpilot at 5:22 AM on July 13, 2020

Look at your battery settings for what apps have been using the battery. It's probably facebook.

OH MY GOD DO NOT RUN WATER ON A LITHIUM BATTERY IT WILL EXPLODE!
posted by sexyrobot at 5:24 AM on July 13, 2020 [13 favorites]

You mention shutting down the iPad, but not closing apps. In my experience, rebooting an iThing doesn't change the set of open apps; so whatever it is that iOS apps do in the background, they may still be doing after the reboot.

If you're running a recent enough version of iOS that it shows the battery usage breakdown chart in Settings, you'll be able to see if anything's been doing a lot in the background: it shows a darker blue for foreground battery consumption and a lighter blue for background use.
posted by ManyLeggedCreature at 5:52 AM on July 13, 2020 [1 favorite]

You mention shutting down the iPad, but not closing apps. In my experience, rebooting an iThing doesn't change the set of open apps

That's my experience too, it's a bit counterintuitive, as I'd normally expect that turning it off should close all the apps, and restarting would start fresh.

I actually had the same issue yesterday - iPad warm to touch, and battery charge disappearing very fast. I closed all the apps (and recharged and rebooted), and it's fine today. The same goes for other times it's begun to feel warm - the solution was closing all the apps that I had basically forgotten were open.
posted by scorbet at 6:04 AM on July 13, 2020

Is the storage very full? I think it chugs extra hard caching stuff in/out of memory or compressing or whatever opaque shenanigans they get up to. Case in point: my 5-6 yr old IPhone 6 was getting really hot last week and after I deleted a gig of photos and rebooted several times it got better.
posted by SaltySalticid at 6:09 AM on July 13, 2020

A lot of focus on the battery here without any real reason based on the wording of the question.

Define “recently”. Did you just upgrade iOS? That sometimes results in heavy load (and high temperatures) for a few hours (or even days on an old machine, especially if you keep shutting it down).
posted by caek at 7:39 AM on July 13, 2020

Mod note: Popping in here to suggest we be mindful of the advice we offer to others, especially things that may be potentially dangerous and/or harmful.
posted by travelingthyme (staff) at 8:13 AM on July 13, 2020 [1 favorite]

OH MY GOD DO NOT RUN WATER ON A LITHIUM BATTERY IT WILL EXPLODE!

This is absolutely not true for a rechargeable lithium-ion or lithium-poly battery. The commonly accepted method to stop a fire in a rechargeable battery is to get as much water on it as possible to keep it cool.

Non-rechargeable lithium batteries are a different matter, but presumably you have been plugging your iPad in to the wall and therefore I can assume that it is rechargeable.
posted by backseatpilot at 8:30 AM on July 13, 2020 [1 favorite]

Does this vary with the wireless/data connection turned on and off?
posted by carter at 8:56 AM on July 13, 2020

The MSDS for small rechargeable lithium based batteries used in my RC cars do calls for 'copious' amounts of water to address a fire, but putting water on a lithium based battery can cause a fire. A MSDS from Apple notes "water may not extinguish the fire, but will cool the adjacent products and control the spread of fire" and suggests 'flooding' the area or using smothering agents. I'll also note that water can react with lithium/electrolyte in the battery to produce flammable hydrogen or hydrofluoric acid which are very bad things.

So that's why a bucket of sand is my preferred method for safely containing a problematic battery.
posted by zenon at 9:56 AM on July 13, 2020 [2 favorites]

Any chance you've changed the case recently?

My grandma's iPad (of similar vintage) was regularly becoming unusually hot and taking it out of her poorly-ventilated case solved the problem almost immediately.
posted by mosst at 10:42 AM on July 13, 2020

You mention shutting down the iPad, but not closing apps. In my experience, rebooting an iThing doesn't change the set of open apps

They're closed - iOS and iPadOS maintain that app history regardless of whether they are loaded and memory resident or partially unloaded or haven't been used since the Nixon administration. It's just a bunch of screenshots and a textfile with the most recently used apps listed in it - the device doesn't have infinite memory of CPU time to keep dozens or hundreds of apps resident all the time...

Check with something like System Status Pro HW Monitor or similar to see if the CPU is churning away at 100% or not. if it is, it's busy. It might be infinitely busy is there's a glitch in a library it's trying to work through. It might complete eventually, it might not. The CPU is thermally limiting itself, so while it might be surprisingly hot, it shouldn't be catastrophic.

Otherwise, wipe and reset and maybe restore a backup, maybe select things down from the cloud and treat it like a new device.
posted by Kyol at 1:17 PM on July 13, 2020 [1 favorite]

I imagine that if the iPad’s getting very hot then your battery is also getting used up very quickly? I had something similar on my (old) iPhone recently. It might have been this issue, as I’d just upgraded the OS, but I don’t know. I tried several times to reset the device (as described here). I’m not sure if any of that fixed it because after around 3 days of this it just went back to normal - not hot, battery not getting run down super quickly.

At no point did the Battery section of Settings show that anything was using the battery, so looking at that was no help.

I’m not sure this is any help, other than to sympathise and say that maybe it’ll sort itself out.
posted by fabius at 12:17 AM on July 14, 2020