Airplane mode laptop power...

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Externet
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Airplane mode laptop power...

Post by Externet » Fri Nov 04, 2011 4:00 pm

How does it work ?
The schematic of my laptop shows provisions or control lines that sense if the power coming into the jack is "below 18V -airplane mode-" :? apparently allowing operation from external power but disabling charging the internal battery; makes sense.

Never seen if there is a special cable to power a laptop from an airplane; nor a special DC? power jack on board. Does anyone know details ?
Miguel
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dacflyer
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Re: Airplane mode laptop power...

Post by dacflyer » Sat Nov 05, 2011 2:41 pm

to add to this
i seen something strange on airplanes. almost under the seat, sometimes between the seat bottoms.. there is a what looks like a low voltage outlet, that looks like a miniature cigarette outlet, bout the diameter of a cigar.. smaller opening than a regular cigarette lighter outlet.

any ideas on this... is this what your referring to as far a airplane mode ? ?

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Externet
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Re: Airplane mode laptop power...

Post by Externet » Sat Nov 05, 2011 3:30 pm

Hi.
That could be a power source for laptops; but never seen a power cord 'for airplane use'

The airplane mode for laptops, as far as I can guess, works by connecting the laptop jack to such lower than 18 VDC source; it is sensed by circuitry and disables Wifi, bluetooth, and any radio features. Also, as said, does not recharge the batteries, only allows operation.

The plug barrel has outer negative, inner positive and a centre pin for sensing something, labeled 'limit signal' on the schematic. But unsure if the sensing is performed by the laptop to determine operation mode (as airplane mode) or the sensing is done by the power adapter as to stop charging, go idle, or else.

Would like to know more about it.

There is something here I just found while posting this, about the sensing/mode ----> http://nerdipedia.com/tiki-index.php?pa ... op+charger
Edited: added ---> It has a name ! ; which makes easier to search for it :
http://en.wikipedia.org/wiki/EmPower_%2 ... adapter%29

Yes, it is 15 VDC, that turns off the charging and radio features. I will check if from an automobile ~13-14V I can power the laptop directly by fooling the sense centre pin on the spare power cord I have. This opens some possibilities. :grin:
Miguel
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haklesup
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Re: Airplane mode laptop power...

Post by haklesup » Mon Nov 07, 2011 11:45 am

SOme airplanes have/had a 3 pin connector that was supposed to be universal. Well, I travel a lot and I can say not many planes have it and on those that do, its not in every seat. US Air was good about it for a while but I haven't flown them for a while. 777s often have USB and 110V inverter power at the seats and most international flights on the 777, 747 and similar large planes always have something either DC or inverter power for first and business but rarely anything in economy. Some of the european carriers have nicer features.

in general its very rare on US domestic flights and carriers. Charger and accessory providors like targus don't seem to even support the interface anymore

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Re: Airplane mode laptop power...

Post by Externet » Mon Nov 07, 2011 12:26 pm

Hi haklesup. Here is something :

http://www.seatguru.com/articles/in-sea ... _power.php

Miguel
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Re: Airplane mode laptop power...

Post by dacflyer » Tue Nov 08, 2011 4:08 pm

wow, them adapters are crazy priced :O

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Re: Airplane mode laptop power...

Post by haklesup » Tue Nov 08, 2011 6:09 pm

Thanks for the seatguru link, that will prove useful as I am an avid good seat hunter, I have to be to stay sane on a long haul flight. I already bookmarked it. I didn't check a lot of airlines but at least for United which I fly the most, I can see they don't put power ports in economy seating ever but first and business are generally well equipped.

As far as the crazy priced adapters, these are usually very compact DC-DC converters with multiple input output voltage capability. Free tips for life is not free if you consider they charge enough shipping to cover the product cost no problem.

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Re: Airplane mode laptop power...

Post by ringo47stars » Fri Nov 11, 2011 11:28 pm

You could turn off your battery manually by renaming ups.exe to something you would remember. To turn it back on just name it ups.exe again and double click on it. Or if you are more comfortable with just taking the battery out then do that. That seems like an unusual thing to do though. If you are using an external power source then the internal battery should augment the external power when it gets too low to handle all the power needed. Then if the problem is you are short of power at the end of the trip you might need another battery.

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