It's a burning phone

It is known that the L5 gets warm during charging or intensive usage but now, due to higher temperature (here is around 30°C/86°F) it gets really hot. Especially if you keep it in a bag or in your pocket. I feel uncomfortable handling it and I’m afraid it might catch fire.
I wonder if this only happen to my phone …


hi I will PM you about this

I think I’ve seen low 40’s at times, but it usually stays between 30 and 35. Granted, I don’t have it powered on all the time.

I consider to build a custom stand for my PP (and future L5) with an CPU-Van on the back. :laughing:

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Check journal for messages about thermal throttling?

To be honest, I have no idea what temperature my phone runs at - and I guess that indicates that it is not running hot - but then it hasn’t had its first summer yet. :slight_smile:

You can quickly check with the preinstalled “usage” app. It has a “Thermal” section, from which I took the screenshot.

Anyway, the support is helping me to troubleshot this … looks like I’ve a faulty battery.


I don’t know about Purism phones, but many phones will have battery overheating issues if they are frequently charged with an out of spec charging device. I personally know of both a case with an iPhone and with an LG phone where this has happened. People will plug their phone into just any type of USB power and never think that it could be damaging their phone or battery.


My daily management is as follows:

  • I leave home in the morning with a fully charged battery.
  • Around 3 pm it runs out of juice and I connect it to a USB port with a USB-A to USB-C cable to make it through the day. It charges little and slowly.
  • When I get home I plug it with its charger. Sometimes it get fully charged before it’s time to sleep, sometimes I leave it plugged in all night.
  • The cycle begins anew the next day

Recently I bought a Varta 57932 car charger for when I travel.
I don’t expect this to do any harm … I’m open to suggestions.


There is a difference between:

I have no idea what temperature my phone runs at


I have no idea how to check what temperature my phone runs at.


What I meant is: I pick my phone up X times a day, at no time have I felt that it was unusually warm, so at no time have I bothered to check its temperature - after 6 months of ownership.

In relatively idle operation, not charging, the temperature seems to be low-30s. I’ll check later today what the temperature is during charging (when it is ready to charge).

Should be easy enough to get a spare battery (from Purism) and fault isolate to see whether it makes a difference.

I wouldn’t be worried about temperatures in the 40s but 85C does seem out of spec!

If the USB-A port is USB 3.x then this seems to be a bug / feature. Apparently the Librem 5 intentionally limits to 500 mA (rather than 900 mA), and as a result, as you observe, net charging at that current is modest. It is enough to maintain the battery charge, so that you can continue through your day, but that’s about it.

I don't know whether Purism in the short term can tell you how to dial down the charge current when charging via the official adapter (PD), which right now seems to be set for a peak current of 1600 mA. That *might* be kinder to the phone and the battery and to the thermals.

I’ve been having the same problem as fiacco. My L5 usually reboots due to overheating when I drive. I had no idea this was unusual.

Are you charging it from the car when you drive?

Are you charging it from the car when you drive?

Yes. I sometimes notice that the phone’s light is blinking, which, I’ve figured out, indicates that it’s getting hot. I always unplug the phone when I notice it blinking. I think that helps prevent a shutdown, but I’m not sure.

Charger may be out of spec. At the very least I would check the charging current and temperature of the battery during charging using the non-supplied charger.

Meaning of LEDs:

You may also want to ensure that your phone’s USB-C PD firmware is current, but that is a more challenging exercise.


I do have a spare battery. I replaced it and temperatures have dropped


Sure, but while 48 degrees on the battery translate to an unpleasant feeling on your hand, 85°C on the charger are absolutely asymptomatic. It happened that, with the phone at rest, cold to the touch, the charger temperature was 85°C. I checked because I was trying to troubleshoot the issue and I noticed, but who knows when this thing started.

Here we go again (just said). This is the new battery, only one charging cycle, now disconnected, phone cold to the touch:

So it wasn’t the battery :sob:

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So are you saying that the displayed temperature of 85C is wrong? i.e. maybe a software problem or a sensor problem. For the record, my charger is saying 22C (just switched on phone, not charging, and is rising slowly as the phone warms up).

It looks as if the sensors are sorted descending by temperature. Maybe something is going wrong in the sort. You probably need to find someone who knows how to read the sensor directly from the command line.

Adding: During charging, the charger is only about 30C and the battery is pushing up towards 35C.

Definitely. I’ve never seen a value between 50° and 80° in three days of experiments. It’s in the 30s-40s or exactly 85. Highly doubtful.

Having a room temperature around 30°C here, no wonder phone internal is higher.
Have you ever put the L5 in a carry bag? Mine overheats.