FP4 battery issue? Low temperature alerts, sudden switch-offs, won't charge


my FP 4 arrived a month ago. I also bought original FP charging cable along with it.

From the start there were days when the phone would display “Low Battery Temperature” alert, sometimes very frequently and often followed by sudden shut off (after which it wouldn’t start again for some time), sometimes less so. I have the feeling this happens more often when the phone is ca under 50 % of battery, not plugged in and in cold environments (say 17 °C). Often it’d shut down after I’d enable wifi and data in the morning (as if overwhelmed). There was also about a week and a half when I didn’t have the problem at all.

I searched the forum, found that removing SD card might help (removed it). I also found it might be a temperature sensor problem. (In which case forum said send the phone back.) I was however down with covid and quarantined, so couldn’t do more than hit snooze/dismiss on the alert and wait.

Then yesterday I got another issue on top of that. After a long walk outside, the phone at 16 % battery wouldn’t charge at all and upon starting would immediately shut off. When I plugged it in, it at least stayed functional, drew energy from the socket, but still wouldn’t charge. I tried dialling ##2886##**. The USB/Charger test said USB OK, charging NOK, current NOK and the charge was -3,8. FP troubleshooting page said wait 90 mins then try charging while switched off.

I did that overnight and the battery would slow charge up to 46 % then stop. In the morning the Battery page in Settings said 0 minutes from the latest full charge (but it was only at 46 %!). I tried replugging, the phone would quick charge till 52 %, then I switched wifi on and it shut down.

I’m now charging it with wifi and data switched off. The battery test says USB OK, charging OK, current varies between OK and NOK.

All the time I’m using inhouse FP charging cable. I’m back to health now so I can finally start solving this. Where do you think might be the problem? What should I claim warranty for? Thanks very much. I’m frustrated.

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Welcome to the forum.

17°C I would not consider cold. My phone charges in temps of 4 to 5 degrees with no problem. -17%deg;C would be an issue.

You can’t claim the warranty for an ‘issue’ as such, you’d rather contact Fairphone and they will try to help. If they fail they will ask you to send the phone in under warranty.

The problem at this point is only subjective, what the cause is, is obscure.

Do you have an SD card and has it been formatted as internal, if so save any data on it and reformat it as external.

You don’t say what charger you are using, it may well be incompatible to some degree.

Best to check more the external options as Fairphone would ask you to do so.

The battery temperature warning seems to pop up once it gets below -15°C, got those frequently on my phone when i was outside. No shutdowns though, even after some 50 minutes in -21°C.

To me it sounds like your phone might actually have some sort of hardware or software fault, if its indeed having trouble charging and displaying those warning messages at the sort of temperatures you mentioned.


Sounds like a problem with your phone to me as well.
I have my FP4 since about 4 weeks and never saw such a warning, even with slightly below 0°C being outside or at 17°C inside. I never ran it to 0% but it certainly never shut off as low as I went, maybe around 10%. Charging always worked fine.
Contacting the support should be the right thing to do. It’s either a battery problem or something with the core module, I’d guess.

Hello everybody, sorry for my slow reply.

I have since managed to charge the phone to 100 % once and used it for a greater part of the week in battery save mode. I installed a battery monitor, but it seems not very useful, as it gives both temperature and charge in hourly averages, so in hindsight everything appears fine :(.

This weekend I took a small hike with my friends in around 0°C and the phone became unusable for almost 2 days. It has been also behaving strangely since - last night it told me it went from ca 40 % to 6 % in an hour, WHILE SWITCHED OFF (??), this didn’t subsequently show on the battery monitor, though. I caught the battery monitor showing the battery as 4 °C, one full day after the trip in room temperature (aaaand: shut down). It now stays at 58 % and says the battery is FULLY charged. I keep it plugged so that people could reach me via phone, which I know is not good, but that way I seem to be able to prevent it from switching off.

I’m gonna write support today and let you guys and gals know about the resolution, once we reach some.

I’ve been postponing this, because my previous phone is pretty much on its way to silicon heaven, the new SIM I got because of Fairphone doesn’t fit into it so I’d have to visit my operator… I fear international delivery times and that they will try to wiggle out of it and pin the malfunction to me using a generic adapter :sweat_smile: (the original wasn’t available in the store, when I ordered the phone! it didn’t say it might cause problems anywhere!) or some such thing. The phone cost me a monthly wage and it arrived 2 weeks later than it should. So I really do hope they’re nice :see_no_evil:.

Yeah, that pretty much sound like a problem with the battery. Sudden drops in charge level shouldn’t happen otherwise :grimacing:

Hopefully support responds fast and you can use your new phone as intended again soon :crossed_fingers:


Can be down to a short from moving between humidity and temp differentials.

You may like to check the dampness indicators, if one is pink it shows water ingress.

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Heya all, back with the result, as I promised. I wrote support, they’re under a lot of pressure now, so in the end also called them - it might be quicker to call straight away.

They were very helpful and nice, had my phone sent to repair centre for free, where it was immediately switched for a completely new phone and sent back. They can’t say so far what the failure was, but for anyone having a similar problem, it may warrant phone exchange, so don’t be afraid to write. Also probably not a battery issue, I’m concluding.

Thanks for your help to everybody! My new phone is working smoothly, having no issues at all. :green_heart:


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