FP4 overheating while not in use

I’ve seen a few topics where FPs are getting hot with use, but mine has started heating up and draining the battery overnight. This is happening when the phone is disconnected from data and wifi, and face down (so presumably the screen stays off). In use the phone has barely ever felt warm (aside from using GPS), but it is uncomfortably hot to touch when this occurs. It results in the battery dying and alarms not going off, so it’s inconvenient as well as potentially dangerous. Has anyone else come across this or can a fix be suggested?

The first time I thought it might be due to the wifi auto-connect and background apps, but this was deactivated after the first time this happened. I checked the battery life timeline on this occasion, was about 50% when I went to bed (about 23:00), drained normally until around 3-4:00 (to about 40-45%) then dropped off rapidly and was flat by 7:00. Apps showing as used didn’t look excessive, with only 1 app showing just over 1 hour’s use since the last charge, the rest <30minutes

So do you enable Aeroplane Mode which disconnects NFC to etc.

If you still have a network connection it could be dialling out repeatedly. (You only mention turning off data and Wi-Fi)

You can also try using the phone in safe mode for a day, or at least overnight with network enabled if you don’t want to miss a call in the middle of the night.

I need to be able to receive calls overnight for work emergencies, so airplane mode is off. No dial-outs showing in logs, while NFC is always off and have never used - I’m not sure there’s any way that could be switching on?

Should add it’s not a consistent event - it’s happened 3 times in the past 6 weeks, and have had the phone since Nov 2021 at this point.

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You may want to check the battery is seated tightly, a poor fit can result in a lot of battery power being used to overcome resistance. My daughter has just mentioned how loose the battery is in her FP4.

Another thing is, can you tell if it is a hot battery. If you remove the back cover you maybe able to tell if the heat is on the electronics, so to speak.

Another thing is to check the battery consumption data which may show an app using a lot of power.

Battery falls out with just gravity if the back case isn’t on, but what can be done to resolve that?

It was the non-battery parts that felt hotter when I took the back case off: to the top right on the back of the phone, and the front being hot in general. However, I wasn’t sure how long the phone had been dead at that point, and whether battery would loose heat faster.

Battery use of the most-used app was 6-8%, nothing else above 3%

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This certainly sounds like something that might be caused by a poor battery contact. Battery seating could be improved with a thin wad of clean paper inserted between bottom of battery and compartment (instinctively I would avoid plastic film). Clean battery contacts and corresponding contacts in the battery compartment while you’ve got the phone open, use isopropyl or high-grade medical use alcohol and a cotton bud, leave plenty of time to dry.

Has the phone been subjected to any physical shocks (dropping for example) or strain (bending, sat on, …)?

Is this only happening overnight?

This might be caused by a faulty SIM or SD card if you have one. Clean those contacts too (those on the cards anyway).

I would advise you to report this to support.fairphone.com (or use the My Fairphone app).

If the problem persists, I would agree with amoun’s suggestion to use Safe mode for a period if you can (that won’t prevent receiving calls but will temporarily set all settings to default values). For example, if this only happens at night, you could put the phone in Safe mode at the end of the day, and reboot each morning.

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Hi, this happened to me the first couple of days after i received my fp4
I was very disapointed and thought about sending it back. However After one week usage (loading all my old stuff, charging several Times) it stopped heating. I cannot tell what happened, but it stopped this over heating which was very very inconvénient. Now i am quite happy with the battery load and i cannot feel any uncomfortable heat even with many apps running. I reckon this is no Real help, but i must say that i experienced this very Bad behaviour, and that fairphone should check that.

Such things can happen when systems are set-up newly or after OS updates.