Also, most laptops aren’t at the 100Wh battery ceiling — in 2025, it’s exasperatingly difficult to find a non-gaming laptop that has a 100 (or 99) Wh battery.

You can use a USB powerstation with USB PD. The computer won’t know about its remaining charge on any powerstation that I’m aware of, but that’ll let you functionally untether for as long as you want, as long as you’re willing to carry the powerstation, plug it in when the internal battery gets low, and remember to charge it.

I keep a small 100Wh USB powerstation in my backpack, and a larger powerstation in the car.

Here’s an 1070Wh powerstation:

https://www.amazon.com/Jackery-Explorer-Portable-Generator-Emergency/dp/B0D7PPG25F/

This is considerably larger (and comes with a lot more electronics), but also ten times that amount of juice. powertop says that my laptop is currently drawing 10.6 watts as I’m sitting here. That thing could run my laptop at the current power usage for 4.2 days, assuming no idle screen powerdown or anything like that.

Today, though, Linux doesn’t have the ability to have a USB power station and treat it as another BAT /sys/class/power_supply device, and there aren’t USB PD power stations that report their charge out there that I’m aware of. If you have a laptop running on USB PD power, it simply acts as if it’s connected to an infinite source of AC wall power.