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The difficulties of providing 110-volt power to your airline seat
- deleted 16y ago[deleted]
- oiujmngbvfgh 16y agoCan't we just have exercise bikes linked to generators in economy class? About time the lower orders did some work.
- sliverstorm 16y agoHey, if I could get something out of it (like fare), I'd gladly pedal away.
- netcan 16y agoOn a long enough flight, I'd probably pay to pedal. Come to think of it. Maybe we should have excercise bikes in 1st powering economy. On board gym?
- atomical 16y agoI feel uncomfortable enough without the guy next to me having a heart attack and possibly killing me as he falls on top.
- jrockway 16y agoPeople sure do envision some strange failure modes for commercial flights...
- merraksh 16y agoGiven that, in most overseas flights, sufficient voltage is available at every seat to power in-flight entertainment, I wonder if it's an easier engineering problem to have a 15-20 volt outlet instead (though I'm not sure if there's enough juice for the extra 2-3A). True, not laptops have the same AC plug, so an adapter would be necessary.
- riobard 16y agoNot necessarily. Some sockets can cope with the majority of the AC plugs in Europe and America. http://img.hisupplier.com/var/userImages/old/selong/selong$71811154.jpg http://img.hisupplier.com/var/userImages/old/selong/selong$7...
- caf 16y agoThat's similar to what Air Canada had on the seat back for the flight I took SYD<->YVR (economy). My Australian laptop plug worked fine with it. So it's definitely doable, and I'd be prepared to bet money that it runs off the same APU that powers the entertainment system.
- jbellis 16y agoSo, why not cigarette adapter DC sockets?
- oiujmngbvfgh 16y agoBecause 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.
- fleitz 16y agoIt 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)
- oiujmngbvfgh 16y agoyes - I think thats the main objection to fitting 120VAC, the thought of an entire flight of teenage girls with hairdryers.
- snom370 16y agoYep. And this is the reason that all the sockets have built-in current protection. Additionally, there are circuit breakers per seat row, which is what I discovered when I tried plugging in my 110W laptop power adapter into one of them. The other passengers on the seat row were not happy when the flight attendant said that they were not allowed to reset the breakers. Another lesson learnt - bring a lower power adapter. :(
- jewbacca 16y agoPerhaps this would be (or would be posed as) a security problem, too. I am not familiar with any specific methods of causing a large explosion that access to a 120V AC socket would allow, which not having access to one would not, with what is currently allowed to passengers through airport security [0]; But considering that producing a cigarette lighter or some nail polish remover in the cabin are grounds to be tackled by an air marshal and prosecuted, an electrical outlet is a hell of a lot of accessible power. [0] kindly disregard my past five minutes' search history, NSA sniffer
- fleitz 16y agoThe difficulty is that everyone wants it yet no one wants to pay for it. (I'm sure it works quite fine in first class)
- stcredzero 16y agoHere'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 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!
- nostromo 16y agoI've considered these, but I've been afraid of taking it through security without causing any headaches. Have you had any problems?
- stcredzero 16y agoI've only had a problem with the Cradlepoint because I had it on and it was warm. The battery? I just put it in my carryon, and it's never been a problem. I spent almost $7000 in cheap airfares in the last year, so this has definitely been tested!
- decadentcactus 16y agoWow, thanks a LOT. I've been looking for something like this forever, guess I didn't know what to search for.
- drinian 16y agoThanks -- I've been looking for one of these ever since APC stopped making theirs about four years ago.
- riobard 16y agoIf 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?)
- gvb 16y agoThere 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 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.
- riobard 16y agoAh, thanks for clearing it up! Another question: I saw many international flights feature a VOD system with a LCD screen that is playing some movies on the back of every seat. Does the power to drive the system enough to charge a laptop then?
- gvb 16y agoI am not familiar with the VOD systems, but I really doubt it. A typical laptop brick is rated at 70W and it probably pulls close to that with a discharged battery. I would expect the VOD display system to be running around 10W. My guess is 1W lost in a 90% efficiency power supply, 5W for the display, 1W for an ARM processor, the rest for the video decoder chip and miscellaneous support chips.
- s3graham 16y agoAll the Air Canada flights I've flown from YVR have a 110 plug too. I've no idea what the voltage/current actually is, but it charges my laptop just fine. (There's generally only one plug for every 2 or 3 seats though.)
- ars 16y agoThey 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?
- a-priori 16y agoThere 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.
- Groxx 16y agoThey already tell you to turn off your Gameboy. I doubt they'd let passengers get anywhere near plugging directly into the power from the engines.
- stcredzero 16y agoThey could run a generator off a turbine in the airstream. A lot of EW pods were powered this way. This would cost a bit of fuel, but there would be no direct connection between the cabin electrical system and the engines.
- vitaminj 16y agoSwitch-mode power supplies are essentially DC rectifiers, which will never ever give you 110V, 60Hz (an AC voltage). One way to change the frequency of a power source is through a double-conversion type AC/AC converter, i.e. 1st stage is a rectifier which outputs a DC voltage - this is an arbitrary DC voltage, but it needs to be within the voltage tolerances of the 2nd stage - an inverter, which reconstructs an AC voltage from the DC link to whatever frequency you like. This setup is also the basis of most UPS systems btw, with a battery connected in the DC link.
- SpacemanSpiff 16y agoA switch mode power supply can do a whole lot more than act as a rectifier. "Switch mode" refers to the turning on and off of numerous silicon switches usually connected to some kind of LC energy storage/filter, and this is the basis of modern rectifiers, inverters, step-up and step-down converters, etc. It is in fact possible to use a switching circuit to convert an arbitrary ac voltage/frequency to another arbitrary ac voltage/frequency directly without a DC link intermediary. This is called a "matrix converter." http://en.wikipedia.org/wiki/AC/AC_converter http://en.wikipedia.org/wiki/AC/AC_converter So it should theoretically be possible to take say 200VAC at 400 Hz and convert this to 120VAC 60Hz. In fact this would probably be more compact/less expensive than the usual inverters mentioned in this article, since these are usually meant to be powered by a low voltage DC source and thus have to deal with taking a low voltage and very high current and first stepping this up to several hundred volts, then modulate it into an AC sine wave. A matrix converter (or even AC-DC-AC converter) would have no such requirement if it were powered from the already high voltage aircraft power bus. At this point I think it's a matter of the technology catching up, since this is a highly specialized application that has just recently become an opportunity for innovation. EDIT: Also - 240W per person? This seems outrageously high as a baseline load. I would estimate more like 50-100W per person on average, with 300W peak (like when the power supply is first plugged in.) The peak loads would not all happen at once unless everyone decides to plug in and turn on their computers at once, in which case the power limiting would kick in...
- vilhelm_s 16y ago"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)#megawatt_.28106_watts.29 http://en.wikipedia.org/wiki/Orders_of_magnitude_(power)#meg... [2] http://depletedcranium.com/what-is-a-megawatt/ http://depletedcranium.com/what-is-a-megawatt/
- evgen 16y agoIt is all about costs. Those engines are producing energy to keep the plane flying at 500mph. If you pull some power to spin an alternator then you need to run the engines faster and burn more fuel (which means you need even more fuel on board at takeoff to lug all of this extra fuel to the destination.) Add in the weight of the various inverters and equipment necessary to make this system safe on an airplane and I am surprised they even bother trying to run provide power to the seat at all.
- nostrademons 16y agoSome math: 120V * 2A = 240W * 300 passengers = 72 kW. That's 1/50th of a percent of the existing power output of a 747. If you figure a $600 plane ticket, I'd gladly pay 1/50th of a percent ($0.30) of that for electrical power on the flight. The numbers get a bit more complicated when you figure in the weight for transformers, alternators, inverters, etc. But fuel is not a major component of this. The math really doesn't support the assertion that it's not cost-effective.
- mrb 16y ago72 kW is 1/19th of a percent of the output of a 747 (140MW). More to the point, 240W is irrealistic for a laptop. Most laptops consume under 40W. With this better estimation, this is 1/117th of a percent.
- 16y ago
- jamesaguilar 16y agoEvery pacific crossing I've been on in the last three years (all 747s) has had AC to my seat. As far as I could tell all the seats had it. Large jets have auxiliary engines that power the coffee makers, the ovens they use for cooking in the plane, the lights, etc. You can normally see the exhaust for this engine on the very tip of the tail. Someone please correct me if I'm wrong, but I believe this article is defeated by the actual fact of the matter that some planes do have AC to all the seats.
- joshwa 16y agoHaving outlets at all the seats isn't the same thing as having a large number of them drawing power at the same time.
- bonzoesc 16y agoThe APU doesn't run in-flight (unless shit gets real and the engines are disabled or need to be re-started). Everything electric pretty much runs off the generators powered by the main engine (in-flight), or ground power (at the gate).
- Yaggo 16y agoInteresting article, but a whopping quarter of kilowatt to every seat? Isn't that a bit overkill? Assuming that typical laptop charger drinks 80 joules of energy per second at most, and since laptops luckily have built-in energy sources for couple of hours, the power output could be time-divided, eg. every output is powered half of the time in 30 minute intervals. Assuming not everyone needs power at all, two power outputs per three seats should be enough. Suddenly we have reduced the needed peak power to 1/9th of the original!
- bonzoesc 16y agoThe OEM DC adapters for Apple laptops prevent battery charging, because some in-seat DC outlets don't provide that much power. I've had trouble connecting a laptop that wants to charge to inverters before, so this isn't without reason.
- InclinedPlane 16y agoThis is a pretty snarky and relatively uneducational article. A lot of speculation, some ignorant rambling (nobody at The Atlantic seems to know where electrical power on a plane actually comes from), and a lot of misplaced vitriol. You'd think people would be grateful that airlines are offering standard electric outlets on the plane at all. http://www.smbc-comics.com/index.php?db=comics&id=2035#comic http://www.smbc-comics.com/index.php?db=comics&id=2035#c...
- varjag 16y agoMakes you wonder how they even manage to power those 500 Watt aircraft headlight bulbs, tens of KW in avionics, coffee machines and kettles, ovens, in-flight entertainment system per every seat etc etc
- gaius 16y agoBecause a) they know at the time the plane is designed the exact power draw of all those bits of kit and b) said bits of kit can be designed from the ground up to play nicely with aircraft power supplies.
- varjag 16y agoBoeing 747 was designed in 1960s.
- paol 16y agoYes and no. The 747 is still in production and has been revised many times since. A 747 bought today will have relatively little in common with one bought in 1970.
- varjag 16y agoIt is still roughly the same energy requirements to lift one in the air and keep it there. Electricity intake is a tiny part of that. Yes there was no in-flight entertainment in mid-60s, but avionics back then were still to a great extent valve-based and consumed gobs of power.
- gaius 16y agoIt's not just the power - it's the weight of the transformer, inverter, etc.
- bradleyland 16y agoThe reason none of those are a problem is pretty straight forward. Each of those systems were designed to be powered by the aircraft's gen-sets, rather than the other way around. When designing an aircraft and its sub-systems, the engineer provides power availability specifications. The people who make the headlights, avionics, and coffee machines are all aware of the common power configurations and design their equipment to work with that specification directly. I used to work on light aircraft (private), which all used 24 VDC. Everything in the plane was designed to run on 24 VDC. Commercial airliners likely have more than one voltage specification available, but I'd imagine it's all DC. Any time you have to convert voltage, you're going to lose some efficiency. Inverters (DC to AC) have some particularly nasty characteristics that make them undesirable on an aircraft. A DC voltage converter would work, but you still introduce some degree of inefficiency. A good switching DC voltage converter can exceed 90% efficiency, but so can an AC inverter. Neither operates at that efficiency all the time though. I know that AC inverters perform best when run at close to nominal load. At lower current levels, efficiency drops. I don't know enough about DC converters to say. Add to this the fact that inverters and converters are heavy, and you can begin to understand why a power outlet at each seat is problematic.
- quellhorst 16y agoSince every laptop has a battery, you could do "rolling blackouts". The laptop doesn't need power the whole flight. I know from going to conferences sometimes just plugging in once in the middle of the day allowed me to make it without being plugged in for the rest of the day.
- orborde 16y agoYou might have failed to consider conservation of energy here. The laptops use a steady amount of energy whether plugged in or not (more or less), and if they're unplugged for a while, then they'll draw more power during the time they are plugged in as they recharge their batteries. In fact, if the batteries are not perfectly efficient and thus don't provide the same energy that was used to charge them, you're now using more energy per time by running it through the batteries first. Of course, doing the rolling blackouts might encourage less use of devices, reducing power use.
- quellhorst 16y agoActually, in OS X my laptop will use less power when on battery power. The clock speed goes down, the display dims, the hard drive goes to sleep faster, the display adapter switches to the less powerful one.
- orborde 16y agoThat's a good point; it might well outweigh the battery inefficiency's increase in power use.
- hjalle 16y agoEven though the articles claims that its a worst case scenario, most people on an airplane wouldn't use their 19", 8kg über-gaming laptop. Most people would probably use more portable versions, ending up in a avarage effect that is way, way below 220W.
- twitter_v2 16y agoI think airlines could pre-wire all seats to be able to provide 110v supply if purchased with your ticket or on-board as an add-on. Then have an intelligent switcher, which only energizes the socket if they have been pre-purchased, reducing the need to distribute live power around the plane. Most people would really only want a few hours of charging. Then you could have a capped number of active sockets per flight of say 50-100 seats.
- savrajsingh 16y agoNobody needs 120v AC -- everyone on a plane is stepping it down and converting it to dc! The solution here isn't 120vac to every seat -- it's coming up with a new DC standard that plugs directly to our devices. The hard work of an airplane based inverter is undone by our power bricks, and energy is lost to heat in both. Lots of industry cooperation needed for this to happen, though.
- samwillis 16y agoThat industry standard DC supply is 5V from the USB port. Stick a USB port in the arm of each seat and sell an adapter kit for common laptops and phones on-board. Although i'm not sure a USB port will supply enough current for a laptop.
- w1nk 16y agoIt won't. The solution is to force everyone to use the 'car' (or cigarette lighter) variant of their chargers.
- joshwa 16y agohttp://www.seatguru.com/articles/in-seat_laptop_power.php http://www.seatguru.com/articles/in-seat_laptop_power.php For those advocating for a low-voltage DC power source, look at Empower--it's installed on more than 40 airlines. 15V DC, 75W. http://en.wikipedia.org/wiki/EmPower_%28aircraft_power_adapter%29 http://en.wikipedia.org/wiki/EmPower_%28aircraft_power_adapt...
- Retric 16y agoFor anyone who was wondering over a 12 hour flight the fuel cost would be aproximatly: (240 watt) * 12 hour * 500 people / 45 MJ (energy dencity per gallon) / .35 energy effecency = 330 gallons * 6.8 lb / gallion = ~2244 pounds. Granted this is probably +/- 30% depending on the fuel, engine effecency, transmission losses etc. For comparison a 12 hour flight would burn ~ 43,000 gallons or 292,000 lb of fuel.