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Use Macbook Pros with 75 watt airplane power ports Laptop Macs
As far as I know, the Unibody Macbook Pros (and probably most MacBook Pros) ship with 85 watt power supplies. Unfortunately, a lot of in-seat power ports on airplanes are limited to 75 watts, and plugging in your 85 watt power supply will quickly overload the power supply. This is not dangerous to the plane or anything, but the power will shut off.

There are two options. First, run your MBP off of the battery, then when the battery dies, close the lid and recharge the battery in sleep mode, as this will draw much less power than running the machine and charging the battery.

Also, and this is a little dangerous to your work, remove the battery and run solely on the in-seat power. With the battery removed, no power will flow to the battery and you'll be able to run at on the 75 watt power from the seat. But ... be careful, save often, and I'm not responsible for the consequences. Consider if the guy next to you bumps the plug and it falls out -- your machine will go off!

I am not an electrical engineer, but these options worked for me. I would appreciate feedback from any EE types on how bad of an idea this is...
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Use Macbook Pros with 75 watt airplane power ports
Authored by: brosetti on Sep 16, '09 08:57:41AM

Apple states that MBP's can be used with the MB 60w power supply but it will not charge the battery. If you don't mind hauling 2 supplies with you, you can safely use the 60w on the plane.



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Use Macbook Pros with 75 watt airplane power ports
Authored by: PabloT on Sep 16, '09 09:00:55AM

Using a MacBook 60W actually charge the battery, only more slowly. A 60W (from a client dead MacBook) is now my travel MBP adapter.



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Use Macbook Pros with 75 watt airplane power ports
Authored by: palahala on Sep 16, '09 09:07:31AM
Just as a side note: running without the battery makes MacBooks run a bit slower, as the battery is needed to supply power for peek usage. See Apple's Mac reduces processor speed when battery is removed while operating from an A/C adaptor (and some benchmarking at Tom's Hardware).

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Use Macbook Pros with 75 watt airplane power ports
Authored by: ScottM on Sep 16, '09 09:13:41AM

Plus, it's a little tough to remove the battery from the Unibodies! :)



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You don't have to pull the battery
Authored by: tbolioli on Sep 16, '09 09:34:52AM

You don't have to pull the battery, just don't let it discharge and it won't charge when plugged in. It is the combination of use and charging that trips the 75W limit. ie; 45 watts for the laptop and 40 watts for charging. If you are not charging, then that 40 watts is not used. Also, there is a curve for the power charging a battery. The power needed to charge a deeply discharged battery (20% left) is not the same as the power needed to charge a lightly discharged battery (90% left). So it may need 40 watts when @ 20%-80%, but after 80% it goes down to 10 watts @ 90% and even less as you make it to 100%.



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Use Macbook Pros with 75 watt airplane power ports
Authored by: cyberdave on Sep 16, '09 09:47:28AM

My 2008 15" MacBook Pro came with an 85 watt power adapter.

My sister just purchased a new 2009 15" MacBook Pro and it came with a 60 watt power adapter, which surprised me.

Checking the specs at http://www.apple.com/macbookpro/, it seems like the 13" comes with a 60 W adapter, the 17" comes with an 85 W adapter, and the 15" comes with a 60 W or 85 W adapter (my guess is this is based on the CPU speed, with the faster model needing the beefier power adapter).



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Use Macbook Pros with 75 watt airplane power ports
Authored by: keytohwy on Sep 16, '09 12:33:36PM

I would think not processor related, but video card related. The new 15" entry level has integrated graphics, whereas the others have a dedicated card. My guess is that the video card is the difference. Your point, however, is still valid, and probably factors in as well.



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Use Macbook Pros with 75 watt airplane power ports
Authored by: Anonymous on Sep 16, '09 03:56:42PM

Does setting the CPU usage to "reduced" help? I'd guess not, because it's most likely (as others have stated) to be related to GPU power consumption.

There needs to be a way to run that in a similar low power mode.



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Use Macbook Pros with 75 watt airplane power ports
Authored by: lairdo on Sep 16, '09 11:17:02PM

I can confirm that the new MBPs from June have two different adapters. I got mine in August and went to buy a second adapter so I could have one at work and one at home. The Apple Store employee asked me my processor speed and told me I needed the 85 because I had the 3.06. I asked who needed the 60, and he said the people with the lowest processor speed.



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Use Macbook Pros with 75 watt airplane power ports
Authored by: RBR on Sep 17, '09 04:43:28AM

It would seem that Apple could rewrite the power management software to add a reduced power profile (manager). It should be rather obvious to them that there is a need for the ability to function in a 75 watt environment, but obviously is not or this problem would not be present.

Has anyone reported this to Apple? (Please do!)



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