Can someone explain what I am doing wrong?

A colleague and I just flew from LAX-NRT (SQ11) on a 747 in C

Initially, we were upstairs in row 11. None of the power outlets on any of the seats in that row had the little green light illuminated, and none of the ports appeared to be working, even after the FA reset the seat.

They then moved us downstairs to row 22 and the green lights were lit on both of our the power ports. I plugged in my laptop, and within 10 minutes, the light (on both of our seats) went out and stayed out with no power for the remainder of the flight.

I then plugged in to the row behind me (man thanks to the guy sitting there!). It worked for about 2 hours, then the light went out and no power!

Am I doing something wrong? Do the power ports just not support the power requirements of a standard HP laptop? Or do the power ports just not work well on these planes?

Thanks