MacBook auto adapter/power inverter requirements?

[StingMe]

A friend needs to power a MacBook on a roadtrip. I've got an old power inverter that indicates 90W output (12VDC, 10A input; 120VAC, 60Hz, 90W output)...given that MacBook adapters seem to be 65-85W won't this be just fine?

The reason I ask is the Apple Store carries the "Kensington Ultra Portable Power Inverter 150" and the description states:

"Only currently available product (other than an Apple power adapter) you can use to charge MacBook and MacBook Pro notebooks"

Huh? Does Apple really mean "Only currently available product at the Apple Store (other than an Apple power adapter) you can use to charge MacBook and MacBook Pro notebooks"?

[PeterW]

Does that old power inverter of yours have a Mag-Safe connector on the end of its cable?

That's the why behind Kensington's claim.

[Jimmypoo]

I use a Black and Decker 100 without issues

[StingMe]

I don't see any special ports on the Kensington, just your standard "holes" (Seinfeld reference, sorry):



My 90W inverter may be cutting it close if the MacBook draws a continuous 85W (that would be quite a lot for those little machines, no?), but the specs I found indicate that the MacBooks ship with only a 60W adapter. Hmmm...

[olnacl]

Why not just do a dry run and see - most likely there's a fuse in the lighter plug part that will let you know if you're drawing more current than it's capable of producing.

[Racer X]

should be fine. Most MB adapters are in the 60 watt range, and the MBP in the 90 watt range.

If the inverter is rated at 90 watts, and you plug in a 95 watt adapter, I doubt you will have a problem, it may just take longer to charge. There is rated continuous power, and rated max power for a limited time. A FEW watts over isn't a big deal. Just don't put a pillow or blanket over the inverter and adapter. let the heat dissipate.