Originally Posted by
F23Coupe
Just experienced a flight where on the 739, the power ports underneath my E- seats turned red after successfully charging my laptop for about 30 to 60 minutes or so. So then I turned to the row ahead of me to connect my ThinkPad and while they didn't turn red, the green light turned off and wouldn't charge my laptop. This was on a half full plane, too. It'd be nice if they can put the max wattage/current draw on the label that says power ports are available in that row. I don't even know if Lenovo sells lesser wattage AC brick adapters.
Lenovo does sell lower wattage adapters: 60W adapters are available aftermarket or CAN ship only with 14" or smaller screens, but the default is usually 90W* simply because it provides faster charging. No
official* adapter should have the capability to break anything, but depending on your system and the software installed you may be harassed by warnings about it not charging etc.. It is possible (from an engineering standpoint) that the system will not use the power at all and continue to discharge, although I've neither heard of nor seen this happening with recent Thinkpad systems (those using the 20V barrel/rectangle adapters).
You can also take the steps I listed a few posts back in power manager (windows lingo, I know... for Linux you hopefully know where you're going with the above parameters). FYI on Windows 8 with the Lenovo software installed there should be an "Airplane Mode" power plan that takes care of most of this for you (whether it does any special interaction with the power circuitry I haven't seen for certain, but it would appear it doesn't). I would suggest starting with this and if you continue to see problems investing in a smaller adapter (perhaps try one first with any outlet, the wattage is communicated by the power adapter and any nags will happen immediately).
*Some of the larger W series have 120W adapters but I don't think those even fit in carry ons
*Unofficial adapters (especially the barrel-to-square tip adapters sold lately) are lazy and tend to skip the circuitry required to communicate the adapter wattage to the computer. This results in a default assumption of 90W's (which is presumably the over-draw getting you in trouble in the first place) so unfortunately the best way to limit your computer is an official(ly expensive) genuine adapter.
Forgot to mention: There have been stories (including some posted here IIRC) of "rolling blackouts" of sorts if the total system demand is greater than supply (since an overload protection system is already in place it would be overkill to actually provide enough power for even half the outlets to draw the standard 120W). While this makes sense to me I've yet to see it in action (most of my issues have had to do with the physical plug and/or bumping into it) so I don't know what it looks like.