Warning! Battery temperature too low, your device will be shut down

Hi fairphone community,

i have my FP3 for about a month now and use it a lot. Since about 3 days the phone started to shut itself down at about 55% battery. Which is obviously annoying. When I reboot it shuts down again after about 3 minutes.
Eventough it is Winter outside this behaviour occurs in my house at about 23 celsius air temperature - so the phone is not really cold.

I use an Apple USB-C charger (29W), and the phone is as stock as can be. I have tried to install os-updates. This also happens in airplane mode.

Any ideas?

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Hi Richard and welcome to our community forum.

This is definitely something you should report to Fairphone Support (our forum here is almost exclusively run by users like you and me) at https://support.fairphone.com/hc/en-us/requests/new. I cannot recall that this (concerning an FP3) has been reported here by anyone else before, so Fairphone should definitely hear of this.


Thx. I gave it a shot and will let you know what they say.


Can you check the temperature reported by the battery sensor? I know the Ampere app (to show charging status of a phone) can display it, probably there are more apps for it.


My guess would be a faulty or miscalibrated battery temp sensor. This MUST be a warranty case and can actually be dangerous!

If the temp sensor reports too low a temperature, at cold temps its merely a nuisance as the phone shuts down. But it would likely report too low temps as well if the phone is overheating. Normally the phone stops charging or shuts down before a battery can get dangerously hot, but if this fails, you could end up in thermal runaway, with the phone - and worse case your house - on fire.

My suggestion: contact support and get that fixed on warranty, ASAP. In the meantime, do not let the phone charge unattended or over night, keep an eye on it when its charging, as a potential firehazard!

Its unlikely to happen, ( there would have to be a second fault in the phone, battery or charger to make it overheat, ) but with the phone unable to detect if things go wrong, better be safe than sorry!


Ampere shows a battery reading of 28.4 C - this seems reasonable, I guess?

Update: These two screenshots were taken shortly after each other : 26.1 degrees, then seconds later the phone reboots.

Let’s hope not. This reminds me of the exploding Samsung Note 7. Good point, I will try to keep safe.

I’m thinking it could be a compatibility issue with the apple charger, damaging the battery in some way, but I have no idea.

In the meantime the phone did some restarts at over 90% battery level - and stopped booting at all. After I removed the battery and put it back in it booted again.

I am still a little puzzled. My other guess would be some kind of humidity or water messing with the inner workings of the phone?

Maybe the temperature sensor is having some sort of loose contact.

In most Android phones, the battery sensor is actually inside the battery pack. That’s why the battery has 3 or more contacts. One is +, one is ground, and the others are to sensors - either analog (3 wires) or digital (for example data+clock for I2C)

if the battery contact is loose, that could explain flaky readings, especially on a digital sensor. So some of the times the sensor reads out fine, but every once in a while, it doesn’t, and might read “zero”.

When the phone is polling it regularly, you might not ever see that “zero” because the phone immediately shuts down as soon as that happens.

If that’s the case the reason is a physical loose contact between battery and phone (which is a spring-contact which is sensitive to that sort of things), so removing the battery and putting it back in might actually have fixed that.

Keep an eye on it, if the issue won’t happen again after re-inserting the battery, the re-inserting might possibly have fixed it. In that case, charging should also be safe.

Keep us updated :slight_smile:


The sensor is inside the battery for the FP1 and FP2 so I guess it is the same for the FP3 (which also has 3/4 pins, I seem to remember.) If it is not a loose contact, you should try it with a different battery. Maybe one of the #fairphoneangels near you has an FP3 to test, or an FP3 battery.

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The loose battery explanation makes a lot of sense - I am a regular runner, and do like to bring my phone. I would have gone for a light IP67 FP3, if it was around, and was now trying to keep it as dry and protected as possible anyway, but did think bouncing would be alright. Back in the day when my S4 mini had an exchangeable battery it also sometimes happened that the battery would lose contact. This is, if true, a major design flaw.

On the bright side: the phone has not rebooted for a couple of hours now.

Thank you guys anyways, also for the tip with the Angels, I was not aware of this program.
As it stands the FP3 will likely not be my summer phone, if it can’t even keep up in winter :thinking:

Update: nevermind, the issue persists.

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The sensor in the FP1 is analog. I don’t know for the FP2 and FP3.

I totally agree with this.

I am afraid the support was nat particularly helpful as of yet:

They suggested to do the following:

" 1. Open the Phone App
2. Dial *#*#66#*#* in the same way you are entering a phone number to make a phone call. Once the last character is introduced, the Service Menu appears showing you three sub-menus.
3. Select Service tests > Test Single
4. Press Battery status check . This test displays battery-related measuring values.
5. Take two screenshots: first when you are charging the device and then when you are not and send them to us.

If you want to stop the test, tap Back navigation key. Choose FAIL or PASS accordingly.

I will be waiting for your reply.
Have a great day!

kind regards from Amsterdam"

This is the resulting screenshoots:

I’m wondering why it shows 0.0 for Voltage. Just did it by myself and my screen shows a value (3.988 at 66%). Also the app you downloaded a few days ago showed a value for your battery, so something seems to be fishy with your cell…

Plus the given value for mAh seems to be a bit higher, than I would have expected, the batteries being marked as having 3,000 mAh.
And the temperature is even lower when charging.
So, those readings are really strange.

I guess, those screenshots can tell them a tale or two. And it’s a first step; better than sending in the phone (I guess).

Fariphone Support thinks this is an issue with the Apple charger, saying that the FP3 is not compatible with the industry USB to Power standard (which the apple charger supports), but only with the proprietary Qualcomm QC3 standard.

I would expect that the phone should just fall back to slower charging without QC3 when the fast charging is not compatible. And this is exactly what it does, i have not timed the charging process, but the phone does charge.

IMHO, FP3 being that sensitive and dependent on proprietary Qualcomm Technology, seems to defy the whole Fairphone spirit. My last phone did not have any Quick charge 3 (a 2016 standard!) and no USB-C for that matter. There should be maximum backward compatibility to widest variety of chargers if you ship your phone without a charger and say: “just use your old one”. I can see, that fast charging requires QC3, but “normal” slow charging should work with any USB power adapter and USB-C cables. After all, that is why it is called: UNIVERSAL Serial Bus.

Anyway, I still don’t think the charger is the problem, because the phone does charge and will proceed to return the phone to my retailer on warranty grounds.

FairPhone support wrote:


The Apple charger does not contain the Qualcomm3 chip and will cause this type of behaviour in your phone. You can seriously damage your phone. Please order a suitable charger and cable either from out webshop or elsewhere.

Find a charger for your Fairphone 3

The reason that we do not ship the phone default with a charger is that we do not want to create unnecessary electronic waste. As most people already have the right USB Type-C charger or cable at home, a default charger might be redundant in your situation.
When you do not have the right charger at home, ask family or friends if they have a spare charger or USB-C cable. Make sure the cables and chargers you use match the technical specifications listed below: then it should be good to go!
However, we recommend to also visit our forum to discuss experiences, compatible brands/products and tips with other community members.
You can also order a compatible Fairphone 3 USB-C charger in our webshop. The cable of this charging equipment also allows data transfer.

USB-C and Quick Charge

The Fairphone 3 uses USB-C charging as it is the new industry standard. It supports features like quick charging and a reversible connection.

Quick charge

The FP3 supports Quick Charge. This means you can supply your battery with new energy quicker than before using a Quick Charge compliant USB Type-C cable. For quick charging, you will need charging equipment that enables this. See the specifications mentioned below.


The port and plug have no dedicated direction in USB-C. This way we avoid damage to the charger or the USB port of your phone as there is no ‘wrong’ direction anymore.


A charger and cable for the Fairphone 3 must have the following specifications:

  • 5 volts (5V)
  • minimum output of 1 Ampère/h (1A, 1000mA) - beware that this will have a slow charge
  • maximum output of 3 Ampère/h (3A, 3000mA)
  • Qualcomm Quick Charge processor compatible, version QC 3.0
  • the cable must have one USB-C connector
  • manufactured by a USB certified brand (if your product has no brand or the brand name does not show in this list, it is NOT certified)
  • must be compatible with a Qualcomm chip, version 3.0 (not all Quick chargers are compatible).
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Sorry to hear that. Must be a bit frustrating to get that reply from support, since this isn’t realy a satisfying answer imho.
With that statement the support implies, that one also should not connect ones phone to any stereo, car, pc or alike, since most of them don’t have QC3.0 but charge the phone while plugged.
For me this seems not just like an incompatibility, but an MAJOR flaw, since you can’t connect your phone to your pc without it charging and possibly frying it in the process.

Also the Apple charger is surely no problem in general, since I use mine (5W-EU from iPhone 4, 2010) as my usual charger since november too.


Well, just get a USB-cable and charge the phone e.g. with a USB port from a desktop PC or else, e.g. borrow a charger from someone else. And then test it! Apple power supplies are supplied for Apple devices and often include special circuirty for device detection and device security.

I have received a replacement

The retailer today sent a replacement, so this was a reason to return the phone (or they didn’t bother) . As I have in the meantime switched to another UnfairPhone, I will proceed to give away the FP3 - I won’t be able to confirm if the apple charger would works this time around . Have fun FairPhoners.

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It’s a shame it’s gone down the way it has - goes to show that a bad support experience can make a defect into a dealbreaker. Please also let FP know about your experience and decision, even if it’s just through linking to these topics, because it may improve the way they handle this type of thing in future.

I imagine the Apple charger won’t work now either, as it doesn’t have that funky chip - though I agree with you that this shouldn’t be an issue in the first place. The U in USB should be preserved, even when phones are capable of using proprietary tech embedded in devices and cables. That was the idea behind the Open Handset Alliance, and it’s a very good idea (even though that group includes some rather evil companies).