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The difficulties of providing 110-volt power to your airline seat

theatlantic.com

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Re: The difficulties of providing 110-volt power to your airline seat

#11

Post by stcredzero »

Here's my personal solution. It works for all airlines. It can also power my Cradlepoint 4G hotspot and recharge my iPad, iPhone, and any device using USB power.

http://www.tekkeon.com/products-mypowerall.html

I bought a male Adaptaplug and a Magsafe cord from eBay, and after 5 minutes with a soldering iron, it works for my 13" unibody MacBook as well. I plan on upgrading to a 13" MacBook Air soon. I should be able to get 14 hours working time from this setup.

As a companion to my WiFi iPad, it's great. The Cradlepoint will run for 18 hours off of it. (I have the MP3450.) Not small enough for a pocket, but it fits fine in most laptop bags.

EDIT: I bet there's a business renting these things out to people at airports!

Re: The difficulties of providing 110-volt power to your airline seat

#12

Post by jrockway »

atomical wrote: post #8
oiujmngbvfgh wrote: post #3

Can't we just have exercise bikes linked to generators in economy class? About time the lower orders did some work.

I feel uncomfortable enough without the guy next to me having a heart attack and possibly killing me as he falls on top.

People sure do envision some strange failure modes for commercial flights...

Re: The difficulties of providing 110-volt power to your airline seat

#13

Post by jrockway »

oiujmngbvfgh wrote: post #7
jbellis wrote: post #6

So, why not cigarette adapter DC sockets?

Because somebody would plug in something dangerous. Believe me there would be some genius with a George Forman plugin grill or similar. There are DC adapter plugins in aircraft - the idea is that they are only sold for laptops and are expensive enough that few people use the.

Not true at all. Every American Airlines airplane has DC power that is provided via a cigarette-lighter socket. It works quite well with an inverter and a standard power brick, or a special DC/DC converter.

I don't use it very often because all the cords that it would require annoys me, and my laptop has 12 hours of battery life. But it is there, leading me to believe that this is not actually a problem.

(I think the fact that it's DC power limits the number of people that will use it, because you have to plan ahead, and nobody ever plans ahead for flights except seasoned travelers. If it was AC power, people would plug stuff in just for the hell of it, instead of reading a book as they do now.)

Re: The difficulties of providing 110-volt power to your airline seat

#14

Post by oiujmngbvfgh »

fleitz wrote: post #10
oiujmngbvfgh wrote: post #7

Earlier quoted context omitted.

Because somebody would plug in something dangerous. Believe me there would be some genius with a George Forman plugin grill or similar. There are DC adapter plugins in aircraft - the idea is that they are only sold for laptops and are expensive enough that few people use the.

It would appear to me that most of the stupid stuff you could plug into a cigarette lighter pales in comparison to the stupid stuff that you can plug into a 120V AC. (eg. You're more likely to find a 120V AC plug on the aforementioned George Foreman grill)

yes - I think thats the main objection to fitting 120VAC, the thought of an entire flight of teenage girls with hairdryers.

Re: The difficulties of providing 110-volt power to your airline seat

#15

Post by riobard »

If 110V is not feasible, can we try lower voltage? 36V DC is sufficient for laptops with correct adapters.

Also I don't really want to work on laptops in tight space anyway. A 5V USB port is sufficient. All Air Canada flights have this. (Due to RIM I guess?)

Re: The difficulties of providing 110-volt power to your airline seat

#16

Post by gvb »

jbellis wrote: post #6

So, why not cigarette adapter DC sockets?

Power is voltage times current. If you supply 12vDC instead of 120vAC (1/10 the voltage), you need to supply 10x the current for the same amount of power.

To supply 10x the current, you need substantially larger wires. Wires are heavy. Airlines don't like heavy, it costs a lot of money over the lifetime of an aircraft to haul non-fare paying weight around.

Another point, 12vDC is not a typical aircraft voltage, so a DC-DC converter would be needed to generate the 12vDC. 12vDC is typically not a native laptop input voltage (19vDC is more typical), so another DC-DC converter would be needed. At that point, an inverter (DC-AC) and normal laptop power supply (AC-DC switcher) makes more sense (efficiencies are similar).

Re: The difficulties of providing 110-volt power to your airline seat

#17

Post by gvb »

riobard wrote: post #15

If 110V is not feasible, can we try lower voltage? 36V DC is sufficient for laptops with correct adapters. Also I don't really want to work on laptops in tight space anyway. A 5V USB port is sufficient. All Air Canada flights have this. (Due to RIM I guess?)

There is nothing wrong with the voltage (110vAC), the issue is power... and to achieve a given power amount (70W typically for laptops), lower voltage requires higher current. See my comment under the 12vDC lighter plug suggestion http://news.ycombinator.com/item?id=1828197.

36vDC would have similar weight problems and, in addition, would require everybody to buy and haul around Yet Another Power Brick since it is oddball.

Re: The difficulties of providing 110-volt power to your airline seat

#19

Post by vilhelm_s »

"I wondered whether, as a technical matter, an airliner could actually produce enough power to keep a planeful of laptop users plugged in through a whole flight. [...] Short answer: No, you probably couldn't make this work."

Given that the power output of the engines of a Boeing 747 is 140MW [1], enough to power 15 copies of the Empire State Building at peak business hours[2], I find this impossibility a bit depressing.

[1] http://en.wikipedia.org/wiki/Orders_of_magnitude_(power)#meg... [2] http://depletedcranium.com/what-is-a-megawatt/

Re: The difficulties of providing 110-volt power to your airline seat

#20

Post by a-priori »

ars wrote: post #18

They already have 400hz power (not sure of the voltage) from the engines. Why not just use a switching power supply to change that to 60hz 110v? Why this whole business with inverters?

There may also be concerns about insulating the flight electrical system from the cabin electrical system. What if there's a surge or huge load in the cabin? You need to be sure that that sort of thing can't affect the engine operation. The easiest way to be sure is to put an air gap between them.
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