TimeAttack

Couple weeks back I had a 15 hour flight with Air Canada on one of their 777-200LRs and I couldn't get the power ports to work with my laptop. When nothing is plugged in the light directly on top of the power port is lit up green (as it should), but as soon as I plug in my laptop the light turns off and no power goes to my laptop. It was a miserable flight since my laptop battery ran out with like 12 hours of the flight left. Do I need some kind of adapter or something even though Air Canada's website says no adapter is required? I just need some help in getting it to work with my laptop for my return flight.

star_world

No - these power outlets generally have a maximum wattage rating, and many laptops (especially larger and/or more powerful ones) can often require higher, especially if the battery is being charged.

You may have been successful getting it to work by removing the battery while connected to the AC power.

TimeAttack

Tried removing the battery and it didn't work either. Strange though, there was one other guy on the same flight that I saw and he didn't have any trouble with it.

star_world

What does the power adapter for your laptop say? I believe the limitation is 75 watts for most AC outlets on aircraft.

cordelli

Guessing that your adapter was drawing too much power, so it just shut you down.

Did you notice if it stayed on with the adapter not plugged into the laptop?

tentseller

90 watts power adapters will overdraw on most aircraft's in seat power, even with the battery out. 75W seems to be the common upper limit.
I use my 65W Lenovo adapter when travelling. Battery just takes longer to recharge.

Absolute

I occasionally have the same issue with my MacBook power supply on AC - so I occasionally bring the one from my MacBook air, which is a 65 watt. Sometimes it'll turn off as soon as I plug in, other times it may shut off after an hour or two.

I usually try two tricks:

1 - Plug the power adapter in, without it connected to my laptop. After a few seconds, connect it into my laptop. This seems to be a relatively easy solution, but as others have noticed, if the laptop starts to charge the battery immediately it could exceed the wattage.

2 - Plug in the adapter; if the light goes out, then unplug it and wait for 2 minutes, and plug it in again. Ad naseum. Sometimes it takes a few tries before it works.

It's all a mattery of current capacity in the system. Either way the AC system is self-resetting, so it doesn't permantly disable the power port… unless the light is red

nkedel

Depends on the laptop and the plane; I've had no trouble using a 90W adapter on CX, with my particular laptop, despite the 75W nominal limit.

TimeAttack

Thanks for the responses guys! I guess the wattage is the problem cause I did the math and it's 91.65 Watts. I guess there's no workaround other than the tricks Absolute posted right?

nkedel

As already mentioned, If your laptop is from a model line (many Dell and Lenovo, possibly others) where you can substitute a compatible, lower-wattage adapter, that's probably the easiest option.

TimeAttack

Unfortunately getting a different power adapter will not be an option for me. Am I still able to charge my laptop battery with the laptop turned off with my 90W adapter, or is charging limited to 75W too?

tentseller

The rating on the power-brick is the maximum that it will draw.

Some 90W will not draw a full 90W when running the computer without the battery or charging the battery only. it all depends on your unit.

nkedel

For most manufacturers, the rating on the power-brick is the maximum it will provide to the laptop, essentially the DC volts*amps. The amount it will get in AC draw will (in general) be slightly higher than what the machine actually gets, with the amount higher depending on the efficiency of the adapter.

Most modern ones also pull less than 1W when not plugged into the machine, although some of the cheapest models work like wall-warts and pull a substantial amount even when not powering anything.

Yup. Depends on both the adapter, and the computer. If it's an older machine, finding a compatible but newer adapater at the same wattage from the manufacturer may help, but then again, it may not.

Turning on the power-saving features on the laptop also may help, or may not.

The 75W limit (or whatever approximation of 75W they are actually using for the circuit breaker) is going to be the same , too, but depending on the adapter and your PC, the current draw from the adapter when the machine is off but charging the battery might be lower (just as it might be lower when on but NOT charging the battery than when doing both.)

Once you're home, if you can blow $20 or so on a tool that won't get a lot os use (unless you start getting into , you could pick up a Kill-a-watt (note the above is a 110-130V model, but I'm sure there are similar things for 200V-250V if you're not in North America) and you can see what your adapter is doing at home in different circumstances.

--

I missed that you are still on the trip and looking at options for the return trip; the main things that apply are what Absolute already mentioned:
1) remember that the outlet is self-resetting, so you can try different things (just unplug for a minute or two in between)
2) check your OS power settings (in windows, avoid "maximum performance" and keep your screen brightness medium or lower), without the battery, or charging with the system off

There's also a possibility that you happened to have a seat with a defective/oversensitive breaker on your last flight, won't know on that one until you get to the next one though.

tentseller

Having been part of a team that added the question "Is you PC plugged in?" to customer service flowchart I should know better.

nkedel

Haven't seen this on anything but AA (where, I grant, I do the majority of my flights even if I'm probably about 50/50 on flight hours with CX) with most of their plans having the older car-DC-port style outlets, but the number of bad outlets I've had on there -- either not functional at all, or where the plug only fits at one particular angle if you rotate it enough times -- is huge.