Airplane in-seat power: DC or AC?

[ross_M]

I read in an onboard magazine on a BA flight that the charging ports were DC and PAX were allowed to use power to power laptops but not to charge them.

What's the situation with aircraft power in general. I mean, most laptops are designed to take 110-220V AC power. So, how does one get them to take DC power? Also, how can one power up a laptop but not allow the battery to charge?

Is there some sort of standardization across airlines or does each one use a propitiatory system?

[PAXboy]

There is now a standard system for travel, aircraft in particular. If you search through 3rd party manufacturers of PC accessories (names cannot be mentioned in here, two main ones begin with T and and K) then look for laptop chargers. Some are marked Air/Auto, as they have DC converters from both car points and airline seats. If you travel much, worth the extra cost to get one.

[Conor.P.M]

Quote
What's the situation with aircraft power in general. I mean, most laptops are designed to take 110-220V AC power. So, how does one get them to take DC power? Also, how can one power up a laptop but not allow the battery to charge?

Laptops are actually designed to run on DC power, the 'power brick' supplied with your Laptop takes the available AC and converts to the correct DC voltage and current for the specific laptop.

As for on-aircraft power, the AC systems use either an EU or US style two pin AC socket, or for DC systems they use either a car cigarette lighter style socket or an EmPower (http://en.wikipedia.org/wiki/EmPower_(aircraft_power_adapter)) DC connector, although in several years of flying I've only ever seen the EmPower system.

For example, I have an Apple Airliner Power adapter (http://store.apple.com/uk/product/MB441Z/A?fnode=MTY1NDEwMQ) that allows me to power my MacBook from the EmPower DC socket fitted to a lot of aircraft. However on Aircraft that have AC power I would need to use the standard 'power brick'. You can also buy a power supply that can convert the in-seat DC supply to the DC required by many popular laptops.

You should first check with seatguru.com (http://www.seatguru.com/articles/in-seat_laptop_power.php) that the aircraft you are flying on actually provides in-seat power (eg: SAS provides in-seat power on flights operated by it's A321 aircraft, but not it's MD-80 aircraft) and that the airline provides in-seat power in the class you're flying in (eg; Virgin Atlantic provide power in Upper Class and Premium Economy, but not Economy).

It's a bit of a mine field as it's requires a bit of research and last minute changes of aircraft can screw up your plans.

[Pontius Navigator]

No aircraft but Eurostar. They have 3 standards of power:

UK-EU and None. As you pre-book your seat you have better than 1 in 3 of getting the wrong power source :)