Originally Posted by
cubbie
I had this problem some years ago with a hefty HP Pavilion model. Billed as a great device for enjoying audio and video, great big screen for watching movies, but connected to an airplane power outlet, charging couldn't keep pace with use, even for less power-intensive activities such as working in Word and Excel. It was probably here on FT in this forum that someone explained to me that the computer needed more power than it could draw from the airplane outlet. Even on a fairly short trip, like Chicago to Washington DC, I was alarmed to see how quickly the battery ran down.
I'm pretty certain that what you experienced wasn't exactly that the outlet's power couldn't keep up with use. The outlet probably turned itself off, so there wasn't any power available at all. I don't think airplane outlets have current limiters; they just shut down if an appliance draws more than around 75 watts.
You can think of airplane outlets as being connected to one-amp circuit breakers, as compared to the 20- or maybe 15-amp breakers that supply typical American outlets. Two space heaters can pop a residential breaker; two laptop chargers (or one big one) will pop an airplane one.