Is there any way to get information on how much power a USB type C connection is delivering to my laptop? I’m using a third party power supply and cable that should provide more power than is needed but my laptop BIOS complains at boot time that it wants more power.
Not nearly enough info !
Laptop powered off usb C?
What model/make laptop?
What is the power rating on the laptop? Volt/Amp/Watts
Make/Model power rating on the power supply? Volt/Amp/Watts/make/model
Is USB-C the only power input to the laptop? or is there another input for charging?
My R Pi requires 3.5 amp power available and most usb-C power supplies only provide a max of 3 amp or less so it is easy to brown-out the power if I don’t get the proper power supply.
I’m not asking that question directly, although that is what I want to know in the end. I’m asking how to find out how much power a connection is providing to my laptop. This information is available to the laptop because I see a snarky message when the laptop boots. But how can I find out how much line power is available to the laptop when it is running? I hear that there can be such information under /sys/class/typec/ but that tree is empty on my laptop.
Before you start digging into configs you should check the labels and user manual for both the laptop and the power supply and verify the power supply meets or exceeds the needs of the laptop.
If the power supply is underpowered you will always get the error message. If it is rated as large enough then it becomes time to search for the details and why .
lm_sensors will give you the data from available built-in sensors when you look at the voltages displayed. Of course some devices report more than others, but there should be at least some numbers displayed that can be looked at. Voltages that are lower than normal are certainly an indication of an underpowered PS. Peripherals that are attached also increase the load on the PS and thus push it closer to the max power load…
I don’t know of any tools that can tell you the power available since that would require tests to determine what the max power out would be without drop in voltage. The PS label should tell you the designed or rated power output.
I would suggest reading labels and user manuals as step 1. Use lm_sensors as step 2.
@computersavvy The problem is that manuals and labels are often not correct, and this may be one of these cases. One of the power supplies I have is a Dell WD 15, which is supposed to supply 3.34A at 19.5v through its USB type c cable… This is just a touch over 65W, which should be more than enough to power my laptop. But my laptop complains. What is going wrong here? If I could find out what power delivery is negotiated I might be able to figure out why my laptop is complaining.
upower --dump doesn’t provide useful information, just whether my laptop is connected to some power supply. GNOME power manager also doesn’t tell me how much power the power supply can supply, at least as far as I can tell.
Divide the battery capacity by the time it gets fully charged from a fully discharged state.
That only gives a lower bound, and probably a poor one at that. Current batteries don’t charge uniformly, to protect them. There are losses between the power input and the battery charge.
What I want to find out is the USB power delivery information.
This link may give you some pertinent info. I just did a quick search for the Dell WD15 and it shows as a docking station that powers the laptop.
So one way to find out part of the information I want is to hook the power supply up to a Dell and get the information out of the laptop’s BIOS. That’s helpful, but it would be better to be able to find out the power being made available to different computers. (I have a Dell, but it is not the laptop that is currently exhibiting the problem.)