Overheating the Librem 5 with USB-PD. Should I always use the charger in the box?

I thought the charge controller was on board of the phone!
I used to charge my old phone through a PC USB or a car lighter USB adapter. That would be particularly convenient with L5, in order to be able to make the battery last until the evening while traveling.
Actually I noticed that with these methods the charging takes really long time, but I thought it was due to the limited power output of a USB port. I didn’t noticed an overheating indeed, it gets warmer with its charger.
You are telling me that I might do some damage?

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USB-PD is a standard for USB-C charging. You can also charge using any regular old USB charger. It will take longer, but it will not risk damage as long as the charger is compliant with the old USB charging. While we have damaged a bunch of devices by charging them wrong during development, I don’t think any of them was damaged due to a plain USB charger.


I feel like this should have a Mythbusters episode (the classical version, preferably, but a DIY community webisode would be fine too). All the way to “ok, but what if someone connected it directly to this highvoltage line…”. Extra points, if anyone can come up with a reason to involve C4 in the experiments :wink:

I’m afraid this might be noncompliant with the USB spec :wink:

Well, for a rigorous testing protocoll…

  1. start with the compliant versions,
  2. move towards older charger,
  3. try some “special” models,
  4. see what happens with scaling up
  5. and/or some accidental malfunctions,
  6. move to intentionally testing the threshold of “at what point do we get them magic smoke appear” and
  7. end up with a finale of reckless use of ridiculous amounts of energy intellectually curious investigation of an extreme outlier (“what would happen if…”) :boom: :crazy_face: :smiley:
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Always use the L5 charger and cable to charge

Oh no !
i’d bought a powerbank for the L5 just 2 weeks ago…

L5 uses USB-C PD3.0 to charger the phone, it is the recommended way. Currently all L5 are not stable on charging, they still have an old firmware, but there is a new firmware to be released which has many improvements in battery charging.
Not all USB-C are PD. and Purism only develops the charge with the original L5 charger, they have not much money to waste it on development, time and testing with old chargers. The old chargers are not safe to charge the L5. You can charge the L5 with any certified usb-c PD charger only for the good performance.


You can uses a Powerbank with USB-C PD certified.

Not quite. We prioritize making charging work well with the provided charger. But we also try to make sure compliant Power Delivery chargers work correctly as well.
At this point we recommend to use the L5 charger, because there’s still some work going on related to PD charging support.


Yes I agree and that is what I said.
I’m happy with my L5 R5 and with the too much work that the few L5 developers do. The PURISM TEAM are true Geniuses!

You can uses a Powerbank with USB-C PD certified.

Thanks for the tips !
that’s what i’ll do.

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But will the phone actually charge when hooked up to a generic usb-charger in a car while, for instance, streaming music? Or will discharge quicker than it can charge?

I’m pretty much exclusively charging my Birch using the USB3 port on my laptop, while debugging it too. That provides 0.9A, compared to the usual wall chargers which typically go between 1.2 and 1.5A. I only have to wait for it when it overheats, not discharges.


As Dorota said above, yes - but currently it will be limited to 500mA by default and you’ll have to bump the input current limit manually if you want to use more - see [MyL5] Received my Librem 5 (Evergreen). In the future we hope that we’ll be able to support BC1.2 spec as well so the higher limit will be set automatically when used with compliant USB-A chargers.


I’ve maxed out the dilithium crystals Cap’n! They’ve given all they’ve got and they canna give no more.


Sounds promising though.

I updated the FAQ with the info from this thread: https://source.puri.sm/Librem5/community-wiki/-/wikis/Frequently-Asked-Questions#211-what-does-the-usb-c-port-support-can-it-fast-charge-can-it-charge-other-devices


Thank you for being focused on the subject here! And (if you allow), one strict, yet another, pretty much similar example (actually link to review) of the USB Power Delivery Specification Rev. 3.0, Version 1.1 (or USB PD 3.0 PPS/QC4/4+ protocol) charger might be this one:

Also (just for the purpose of initial question here) only thing that I might note (or guess, related here only to this post linked example based on CY2311 controller) is that Librem 5 users should probably avoid charging his Purism Linux phone from such USB-A port (as shown within liked charger review or any other USB-A port, especially if it doesn’t support QC4/4+, IMHO, non-expert one). As well, what I’m trying to make, in addition under this thread, as understandable (point) here, is that (on the other side) PinePhone will not even recognize that someone (users of the PinePhone already know that) tries to charge it from this (as linked) charger USB-C PD3.0 port (or Librem 5 original charger USB-C PD3.0 port).

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And, currently 50% off (for testing purpose :face_with_thermometer:) on RP-PC112 that is based on a Weltrend WT6636F USB-C interface controller, certified by the USB-IF USB PD3.0: “However, it lacks PPS support which would otherwise make it a perfect charger.

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