Question about chargers

The specs on my L5 charger is: 18W (5V=3A, 9V=2A, 12V=1.5A)
As I use it in Sweden, the wall plug is plugged in to 230V, but I have no idea which output it has (or maybe it varies according to charge level of phone?)

My Dell laptop charger has the specs: 45W (5V=3A/15W, 9V=3A/27W, 15V=3A/45W, 20V=2.25A/45W)
It seems that charger also works with the L5, which is convenient when using the same USB hub for both laptop and phone to connect to screen, mouse, etc.

But is it safe for the L5 long run? How much current/power/voltage can the phone negotiate without battery or charging unit in the phone gets damaged?

As far as I am aware, currently Librem 5 would always negotiate 5V.
So the 9V, 12V and 15V options are never used.

The maximum that Librem 5 negotiates is 5V 3A.
Depending on the charger/hub, it could negotiate less.
You can read the negotiated value using the following command:
sudo cat /sys/class/power_supply/tps6598x-source-psy-0-003f/uevent

POWER_SUPPLY_CURRENT_MAX=500000 would mean 0,5 A
POWER_SUPPLY_VOLTAGE_MAX=5000000 would mean 5 V

I can’t tell you if it is safe to use the Dell laptop charger on the long run.
I guess that:

  1. It is likely safe.
  2. It will depend on the negotiated protocol as some protocols would produce more heat than others.

As far as I am aware, the Librem 5 is smart enough to stop the charging if it gets overheated or something. As far as I am aware this is visually shown by blinking red LED.

I use “as far as I am aware” because I might be mistaken.


With the Dell charger plugged in:


I guess that is what I want to see :slight_smile:

Note though that in the case of the current that is the maximum. The actual current being used at any one time will be some other number <= the negotiated maximum. (Some other magic cat /sys/... command may get you the current current.)

Personally, I use a USB power meter.

I guess the general answer to “is it safe?” is: yes, provided that both ends correctly implement the USB-C PD specification and the phone end is configured correctly. (Out of the box the phone end will be configured correctly so as long as you haven’t been issuing magic I2C commands, that aspect should be OK.)