Filed under: Portables
Mac travel tip: car power for your MacBook Pro
For all the wonders of the MagSafe connector -- scores of marriages saved and pets kept from the pound, as laptops that would have otherwise experienced impromptu gravity testing remained happily on stable surfaces -- there's been a remarkable gap in the charger offerings for Apple laptops since its introduction: no sanctioned car chargers. This is a point of contention for those of us who use our laptops as DIY entertainment centers on long trips, and has led to some family tensions in my household ("Why do the kids have to watch DVDs on MY machine?!?").MCT does offer a homebrew solution that grafts a MagSafe connector onto a Kensington AC/DC adapter for universal chargeability, but at a fairly steep price; the basic conversion of a MacBook or MBP adapter to work with a DC transformer is cheaper, but still a little scary. With these limitations in mind, I went for a somewhat more traditional solution: an inexpensive, 96-watt inverter (DC to AC converter; I got mine for $10 on woot.com but there are other models and other deals) coupled with the lowest-wattage adapter available that would still run my MacBook Pro. In this instance, that's the 60-watt MacBook adapter, which runs and charges the MBP under all but the heaviest load and also is substantially smaller than the 'big brick' MBP adapter; works like a charm in my car. If you get a second charger for home use, might as well make it the MB adapter and add the inverter for mobile fun.
DISCLAIMER: Any use of an inverter, off-spec or off-brand power adapter, or other unofficial charger is at your own risk. I Am Not An Electrical Engineer.
Reader Comments (Page 1 of 1)
Michael Rose said 9:17AM on 6-08-2007
Oops! MB power spec changed to 60W from 65W, thanks for the correction.
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R. Cabell said 9:40AM on 6-08-2007
I know you're not supposed to use the MagSafe Airline Adapter in a car, but has anyone actually tried it?
And, does anyone have any idea why it's a Bad Idea? Is the car power to variable and dirty, is it underpowered, etc. etc?
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itguy07 said 9:41AM on 6-08-2007
Rumors have it that the Apple Airplane cord does indeed work with a car's cigarette adapter. I've got a Powerbook, so I'm not sure.
However, I wish iGo would make the tip already. That would help me keep my existing iGo investment.
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Shahryar Rizvi said 10:43AM on 6-08-2007
Wait why're you using MB adaptor for a MBP? If you were going to buy a 2nd charger, why not buy a MBP charger? Is it because a MBP charger would be too much for the inverter? (in your case, a 96-watt). What's the drawback of the lesser power MB adaptor when using with a MBP? It powers but doesn't charge also?
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Michael Rose said 11:31AM on 6-08-2007
In theory, the MB charger should either run or charge the MBP but not both. In practice (my experience), it charges and runs simultaneously just fine unless I'm doing something particularly strenuous like running Vista in Parallels. Like I noted, this is UNSUPPORTED and your mileage may vary; you probably should test an MB adapter with your MBP before committing the $80.
The reasons for the 60W MB adapter versus the 85W MBP adapter are threefold: It's smaller and easier to pack/fit in the front seatwell; it puts less strain on the inverter, letting it run cooler and with less risk of blowing a fuse (and lets you get away with buying a lower-power, cheaper inverter in the first place); and I happened to have extra MB adapters in the office. :)
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Eleventeen said 12:17PM on 6-08-2007
I'd heard the reason you aren't supposed to use the airline adapter in your car is because the airline power system puts out something like 16-17 volts, whereas your car is designed for 12 and nominally (not under a full load) is like 14. The airline adapter might not function with a lower voltage than what it's designed for...plus I heard they don't work that well to begin with. The product description on the Apple site even states that it is meant to provide power only, not charge the battery.
You're much better off doing what the author did by getting an inverter. Most in car units will allow enough wattage to use *and* charge your MB/MBP, and a lot of the newer ones have pretty good buffer and shut down options in case it's not getting enough voltage/wattage from your car power line. I have an old TrippLite adapter hardwired into my car, it bypasses the internal cigarette line so it's available to power even when the car isn't running, and provides a more stable power signal than thru the cigarette line.
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deleted said 3:55PM on 6-08-2007
I'm not a typical user. I realize that. Is there a way that isn't too hard or too expensive to hook my intel iMac into my car? Screen real estate is too small on the laptops and I don't have unlimited money so I take my one new iMac back and forth to work with me and also on trips (I use an iLugger bag to keep it safe and undamaged).
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alex said 8:43PM on 6-08-2007
I'm a EE! :-D
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