Wonder if anyone knows the answer to this. I'm due to fly SAN-LHR-SAN and the aircraft type is showing as A350 (351). Thinking about using my laptop on the flight - travelling in WT. It looks like there is a US type mains outlet between the seats. I wonder if it is powerful enough to power a laptop. My laptop requires about 90W peak while charging a battery and using the laptop but drops off to about 40 - 50 Watts on a fully charged battery.

Alternatively I'm contemplating carrying power bank as I don't think the battery will last the whole trip.