A problem I had with the Librem5 and the PinePhonePro is the ratio of charge time to discharge time. The Librem5 would only draw 500mA from a regular USB port which is not enough to charge it when in caffeine mode. I was told that BC was being worked on and there was no mention of support for “High-power SuperSpeed” which gives 900mA. I haven’t done the tests on this recently, I have to repeat them with more recent charging hardware.
But if the charge speeds are still limited then a battery that’s a separate thing isn’t going to work well.
It was being worked on three years ago and has been supported in released kernels since November 2022. With BC1.2, 1500mA can be drawn; for more than that, you need a USB PD source (up to 3000mA).
Regardless of the automatic detection result, you can override the limit manually if you know that the source is capable of providing more current.
A plug and play design would be nice for a modular phone, like swapping out car parts so I don’t have to risk finding a blank spot on a circuit board to dremel through and run a wire to an added peripheral. I did that on an old gameboy a long time ago, looked weird with a 6 amp car toggle switch on it.
I’ve done tests on all the phones and chargers that are convenient for me. The Librem 5 will draw 1.5A on a BC port and 2.0A on a regular PC USB port that has no support for BC or PD (spec violation?). The best charge speed I’ve got is 11.2W from a USB-C monitor, I don’t know if that is using USB-PD or just sucking a lot of power on regular USB. The only device where it manages to negotiate a voltage higher than 5V it interacts badly with and doesn’t charge properly. In most cases it performs better than the PinePhone Pro but in the cases where it has problems (AliExpress charger and Dell Dock) it charges very slowly.
The Librem 5 will draw 0.5A from a USB-A port in absence of BC1.2 signaling. The only way it could set the current limit to 2A is when it’s negotiated over PD (not counting bugs that are unknown to me if such exist, of course).
It’s never supposed to negotiate a voltage higher than 5V. If some source provides it a higher voltage, it’s probably broken and I’d be very careful with attaching anything else to it.
Fortunately it’s not such a big deal for Librem 5, as it’s able to take up to 14V on Vbus - but using higher voltages causes the risk of damaging CC lines with short-to-Vbus events, which is why the PDOs have been limited to 5V in the first place. On Evergreen phones the risk is very small, but still non-zero (it used to be much higher on earlier revisions though).
That will tell you what the actual result of the negotiation between the Librem 5 and the power source was. What protocol. What (maximum) voltage. What maximum current.
That will answer your implied question:
There is no problem with a power source offering voltages higher than 5V but offers can be rebuffed in the negotiation (and that should occur for any voltage above 5V).
The actual instantaneous charging current will change throughout the charging period (and hence likewise the instantaneous power). All other things being equal, when charging a relatively empty battery, it will start high (around 2A) and reduce (to maybe a few hundred mA by the time that the battery is almost full). So if you want to see maximum power, you need to start with a relatively empty battery.
…and /sys/class/power_supply/bq25890-charger-0/input_current_limit will tell you (and let you override) the USB input current limit as used by the charging controller (which if everything works correctly should match the result of PD/BC1.2 negotiations).
What happens if a Dell 65W USB-C laptop power supply is attached to the phone? Will it fry the USB port? I’ve charged many phones with my laptop power adapter and never had a problem.
If it is compliant to the spec, it will not. If it is not compliant to the spec, it might.
You really need to get the accurate specifications of this power supply. When it says “65W”, that just means that 65W is the maximum power that it can supply, for some choice of voltage. You need to get the full list of voltages that it can supply and the maximum current at each voltage.
If it’s compliant, then you don’t really need to: you know that it will provide at least 3A at 5V, 9V, 15V and 20V. If it supports 12V (which isn’t required by the spec), it will also be at least 3A. The spec requires that a source that claims a specific wattage has to first max out 3A at lower voltages before moving to higher voltages, so you know that a device that needs specific wattage will work with any source that claims the same or higher wattage.
This doesn’t apply to pass-through appliances like docks though, as these may reserve some power for internal operation which may vary depending on used voltage, which is how you end up with docks that can’t charge the Librem 5, because the remaining available power is too low at 5V.
As someone daily driving Librem 5, I must say that skimming through these notes about amperage and watts, I seem to be getting away with ignoring this problem entirely.
Solution:
buy 2 Librem 5’s, not only one
buy 5 batteries for Librem 5’s
buy a spare battery charger
buy 2 3D printed super strength Librem 5 back plates that are easier to remove and never tear from constant detaching and attaching
As a user:
The spare battery charger is super slow. It probably charges in a day or so. But it seems to ignore some limit to how much charge we can charge, and probably charges the battery to have more energy than if we charged the battery using a Librem 5 unit
The spare Librem 5 is used as a charger also. In particular, if it is powered completely off it charges the battery faster than anything else I have and much faster than the $10 spare battery chargers I bought off of Jeff’s junk store online.
Usually the $10 spare battery chargers off of Jeff’s junk store have been total junk, but after buying about 12 or 15 of them I have 3 that are really nice and work well, but 2 of them broke, so now I basically have 1 super reliable independent charger selected by process of elimination
Using this strategy I am daily driving. I don’t care about amps, nor about charge rates, nor anything like that. I have 100% uptime on my phone, it never needs to charge unless I feel like plugging it in while I sleep to ensure it never dies if work calls me during the night.
Right now I woke up in the middle of the night and was on the PC for a little bit. While doing that, I didn’t have any good lights so I turned on Flashlight on the Librem 5 and pointed it at the ceiling, to fill the room with light. It’s been that way for an hour or two. Since my Librem 5 has infinite uptime and effectively infinite battery, I don’t care. I’ll probably pass out again soon and sleep a bit more before work. When I do that, I’ll swap the battery out for one that charged yesterday – during a time at which I was using my phone and not charging it, since batteries are independent.
Yesterday morning I woke up and watched a 1 hour youtube video on my phone. Then I toggled the battery out and went to work. The battery that I put in lasted for probably 7 hours of the 11 hour work day, and nearer to the end I noticed the phone died so I threw in another battery, since I had brought along 2 or 3 spares for the work day. Then I came home, fell asleep, woke up, and played around with my phone in bed. It had been in the middle of charging for the fun of it, but I took out the battery and put that battery quickly into the other spare Librem 5 to be used only as a charger, which enabled the battery to keep charging while I poked the phone in bed and did web browsing without needing it to be attached to a wire.
I cannot imagine going back to an Android or iOS phone, as I assume the absence of the battery swap solution would make them extremely dumb. Later this year I will go on a 4 day vacation to the wilderness with no electricity. I fully expect my phone to be ready and available for the entire 4 days, since I’ll charge my suite of batteries prior to leaving and probably charge some of them with the $10 chargers from Jeff’s online junk shop that don’t honor the maximum charging limits and give the batteries probably more energy than you get from plugging into the wall.
FWIW even though it’s rated for 4.35V, the battery should only be charged up to 4.2V because the modem (and perhaps GPS module too? Would have to check to be sure) is only rated up to 4.2V.
(unless you don’t use such battery with the Librem 5, then feel free to charge it up to 4.35V )
Other than that, it’s normal and expected for slower charge to end up with higher capacity. You can slow Librem 5’s charging down too by manipulating /sys/class/power_supply/bq25890-charger-0/constant_charge_current.
Or maybe not. Depends on what specific knowledge you are referring to.
If I interpreted @dos correctly, he said: only do that if you want to damage your modem.
(where “that” means “use an external charger that charges to 4.35V”)
(Now if you carry a multimeter with you, you can probably manage the situation but that’s not very convenient, for a range of reasons.)
So charging spare batteries in a spare Librem 5 is likely a safer option.
I guess what I was saying is approximately “trust but verify”. Yes, you can just trust that the charger is compliant. Or you can start the verify process by getting the full specs (and see that it offers 5V and see what maximum current it offers at 5V).
Another way of considering it is … if you use a laptop’s charger, that charger wasn’t necessarily marketed or engineered as a general purpose USB-C charger. It only really has to do one thing i.e. it has to work with the associated laptop. It may only have been tested by the laptop manufacturer doing that one thing. I realise that that is not in the spirit of compliance, with either the USB spec or the EU regulations.
Above is from the top port of the HP z640 which is documented as BC.
I get the same result when it’s plugged in to the bottom port which is documented as having no support for BC or PD.
When mostly charged it was drawing about 1.3A, but now the battery is down to 72% and it’s drawing 1.75A at 4.7V and /sys/class/power_supply/tps6598x-source-psy-0-003f/uevent still has the same charging details.
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