Power outlets
 

I was wondering whether somebody had experience with power outlets on Continental airplanes, particularly on the Boeing 737s. Recently I had two flights and wanted to charge my laptop computer, but it just didn't work. There are plenty of power outlets, but just as I had plugged it in, the green outlet light would go off and no power would be available. On the first flight, the flight attendant just didn't care and said she was not an electrician (unfortunately that's too often CO's customer-service attitude), on the second flight at least the flight attended tried to explain that my laptop possibly was drawing too much energy. I couldn't follow that example, it's a standard Dell laptop and not a vacuum cleaner. He explained that the circuit was designed to shut itself off against overloading, otherwise the plane would lose power and we would fall off the sky. (Honestly, that how he explained it!) He said he had just tried to charge his iPhone and it took him several attempts to finally get it charged.

I wonder what happens, if those plugs are not working and for decoration only? Maybe somebody wants to share some insight for my further flights on CO. I would think that my experience is not unique, or am I doing something wrong?

The power limits are very low, something like 75W. With 85-90W laptop adapters common these days, it's possible the FA was correct.

It took me a few times to get my laptop to work on Monday.

The green light would turn off like you indicated. I eventually got it to work for 2 hours of my flight.

I actually believe that you can plug a grounded outlet in wrong. I think I was plugging it in too high or two low the first few times I tried.

Might want to feel around a little bit.

The flight attendant is exactly right. The power limits on the in-seat sockets are very low, and once you hit the power limit it trips something that's like a breaker that cuts power off.

Take a look at the charger for your laptop. There's probably a voltage and amperage rating on it. The maximum power draw is the product of those 2 numbers. If that number is > 60-70W, I wouldn't be surprised if your laptop trips the breaker.

You almost certainly have a 90W laptop. I don't think there's a lot you can do besides bring an extra battery.

I had no problem using the power outlet on any CO planes until recently when the same thing happend - the green light would go off when I plugged. I tried everywhich way but it just did not work. Frustrated, I just used my battery until it was dead. Then looking at my plug, I noticed that the prongs were bent - my dog unplugged it running under the charger and it got bent. I squeezed the prongs with my fingers, tried it again and it worked! A few days later, the same thing happend - it got unplugged from the wall and the prong got bent and it would not work on the plane until I adjusted the prongs.

I don't know much about voltage limitations but for a standard Dell laptop, I think the sockets on the plane are sensitive compared to wall outlets (afterall, same bent prongs works in the wall outlets). Now I carry an extension plug that has straight prongs.

Hope this helps.

ONe workaround I've read about is pulling your battery, so you aren't charging the battery, and using plane power for direct power (this is supposed to use less than the wattage limit of the plane power system).

Downside, if they cycle the power unexpectedly your computer shuts off immediately...not too terrible if watching movies, but if you just lost your word or excel document before a save, that kinda sucks.

I agree. One time I can't get my standard US prongs to work (green light goes off), but when I plug it through a UK-type adapter, it works.

I can't power my laptop and use it at the same time. I can sometimes power it when it is turned off to give me a bit more life over the course of the flight. Not great, but better than nothing).

I think they're designed to *power* but not *charge* so the previous reply to pull you battery, if possible, should work. YMMV.

Explain to me how this is a workaround - if the plug doesn't work, how do you use the plane's power?

It's not that the plug doesn't work, it's that the outlet is designed to deliver only a certain wattage, like 65 or 75, and if the draw is in excess, the circuitry shuts power off to the outlet to prevent overheating or pulling too much power from the circuit, like when a circuit breaker trips on your home when the line gets overloaded. Not sure of the specific amount, and many laptops today draw 90 watts or more when charging the battery, but draw much, much lower wattages when simply ONLY delivering power, and not charging a battery.

I understand the design of overheating or pulling too much power; however, my experience with bent prongs indicate that the light does not work if the prongs are not aligned but when gapped closer it does. So in the case of bent prong, this is not a workaround, right? I think there are two issues here - faulty prongs and high wattages - right?

Dear fellow flyers, this is/was my first post and I'm positively impressed by the quality and quantity of the replies, thanks!

My Dell is a bigger one and indeed uses 90W. (I also have a smaller Lenovo which only needs 65W.) With due respect to the professionalism of Boeing's and CO's engineers and any technical limitiations, I wonder how it can be that the circuit doesn't support 90W - do they expect us to charge handheld radios only? I would assume that most people will charge laptops (particularly as DirecTV's IFE is now USD 6 on CO.) The flight attendant mentioned that he had problems even charging his iPhone and that's certainly not like a vacuum cleaner.

As much as taking out the battery seems a smart work-around, given the unstable power supply I wouldn't want to risk losing my data once the power suddenly goes off and I have no back-up battery.

Next time on CO I will certainly try to put the prongs straight and upside-down, but I'm not sure if this will help as I tried four plugs on both flights and am sure that I used several positions.

I e-mailed CO's Customer Service with the same question but haven't heard back from them (yet?). Once (if?) they reply I'll post their response here.

Happy flying!

Another thing that works for me is turning the power settings down on my rig. Use 'power saver' mode, turn down the screen brightness and throttle back your graphics hdwe if possible.

Alternatively, I try to come on the plane with a fully charged battery. This way, I can have the performance turned all the way up with full screen brightness. The battery isn't pulling any juice so it's like having no battery in there at all.

The other choice is to turn off the rig and charge only.

The engineers have to set some upper limit to the capacity of the outlets. No, they weren't meant for high power-draw notebooks. As far as I know, they don't modify the generators on the AC so the seat power system has to fit within the envelope of 'surplus' power provided by the generators.

I had an after market empower adapter for one of my Dell computers did just that. Only supplies the power but does not charge the battery. Even plugging it into a regualr wall outlet. I called the manufacturer and was told Dell designed their computer only allows charging the battery when using a genuine Dell charger. I got a Dell charger and it worked.

Is that on all planes, or do the 772s have a higher limit than the 737s?

Last time, (again, this was a 772 and not a 737), I had my computer plugged in and was charging as well. That being said, my laptop is a netbook, which, using tlawrence85's formula, is only 30.02W.

I had this problem with a beefier Dell a while back on another airline, so it's not CO specific.

Ultimately I found that the power cut-off varied a decent amount between seats, so I ended up plugging into a different socket which worked better, cutting out only occasionally and resetting relatively quickly.

I would give them the benefit of the doubt and assume that 80W+ laptops were not something they anticated when they installed the power systems way back when...

Remember that if you're on the 772 in BF, you also have the USB port, which can be used for devices than can be charged that way (e.g., iPod, etc.). Won't help with the laptop, of course.

Way back when?

My 2007 model macbook pro is on an 85W charger.

It ain't your living room. There's limited 115VAC 60Hz generating capacity (most aircraft equipment is 115VAC 400Hz, 28VDC, or 270VDC) on the aircraft and higher power delivery to each seat would require larger wires, which means more weight. Same reason there's 2 outlets per row instead of 3. Is it worth the extra 50 pounds (WAG) of wiring to provide 140W/seat instead of 70W?

Most road warriors are carrying smaller (~12-14") laptops with 45-65W power supplies. The leisure travelers have and are moving toward low power devices (netbooks, iPads, iPods). I can see how it doesn't make sense to take the weight penalty to support the few guys with portable desktops or who have chosen larger power adapters (for quicker battery charging).

A problem charging an iPhone (which can't draw much more than 5-10W) is a defect. The 90W laptop is out of scope.

ITYM 30 watts, likely at 19V on the DC side.

Solution: Power Block designed for use on aircraft
 

Laptop manufacturers offer power blocks/transformers that are made for aircraft. I have one from HP. It has a switch on it that allows it to 1) supply power to the laptop and charge the battery or 2) supply power to the laptop only.

I've never had a problem since purchasing this and previously I had the same problems outlined in this thread.

Often I have to jiggle the plug before it sits just right and lets me charge my 15" MacBook Pro. It's not a very secure outlet. It will also often turn off once my computer is fully charged, and I'll have to plug it in again. So it's finicky.

I imagine a big part of it is the low current limit. A difference of 15 or 25W doesn't seem like a lot for a single outlet, but multiply that by four outlets per row and 20-30 rows, and you can see why CO is trying to ration us. My guess is also that the AC/DC converter is at the seat since running high voltage wires throughout the plane would be a bigger risk. Having used such converters before in other situations with higher current output, I can tell you they are unreliable at best and create a large amount of excess heat. I'm thankful that CO has them at all.

Difference between PWR on 737 and 777
 

I'm one of those guys that runs a powerful laptop for engineering work. I can attest that I've never gotten it to work on any 737 no matter how it is plugged in or from one seat to another.

I run the factory supplied 135W adapter (Thinkpad W510), it never works, it'll trip it every time on a 737. On a 777, it works just fine. And no I can't use a smaller power supply, if I use a lower wattage adapter, BIOS will slow the machine down to being just plain unusable. Its no fun carrying around a 2lb brick...

So I always go on with a full battery, low brightness and I'll get about 90 minutes before I have to go to watching the History channel........

As a point of reference, with a previous machine that only pulled 90W, it was hit and miss on 737s, usually hit (Thinkpad W500).

Flew Co 1776, IAH-PHL, and used the power outlet with my Dell E6400 without any problem. Loved the DIRECTV also.

I am running a Dell M4600 Precision Mobile Workstation with 180W power adapter. The simple act of plugging in the power transformer (without the laptop even connected to the other end) made the green light go off. So, it doesn't matter if I pull out my battery. I guess that the transformer running in idle alone draws too much power.

Good lord 'n' butter! What the bleedin' heck does your laptop do that requires a 180W power adapter? I mean... sure, "Mobile Workstation", but does it have a toaster? :)