Interchanging MacBook (60W), MacBook Pro (85W) power adapters

MacFixIt reader J.E. de Sequera recently inquired about the interchangability of MacBook and MacBook Pro power adapters. He writes:

"I bought an extra 85W MagSafe Power adapter for my wife's MacBook. The packaging indicates that it is for use only with a MacBook Pro or MacBook. (I have a MacBook Pro and thought it would be good to have an adapter that we could both use). The Apple store employee thought it was a bad idea to use the 85W with the MacBook, as the MacBook comes with a 60w adapter, even though Apple's packaging for the adapter indicated it was also for use with a MacBook. I called Apple for a more definitive answer, but was unable to get one. Their information didn't specify whether it was OK to use it or not OK to use it. A product specialist at Apple commented that although the packaging indicates use for the MacBook, the power supply would charge a MacBook slower and didn't recommend extended use."

By default, the MacBook Pro uses an 85W power adapter, while the MacBook uses a 60W power adapter. Both adapters use the same MagSafe connection point that will fit either model.

So are the two adapters interchangeable? Yes, with a caveat. The 85W adapter can be used inconsequentially with both models. It will provide ample power to both the MacBook Pro and MacBook, and will not damage the latter despite a higher-than-necessary wattage.

The 60W adapter can also be used to some extent with both the MacBook Pro and MacBook. However, the lower-power unit may not deliver enough power to MacBook Pros to offer simultaneous charging and operation. In other words, while the 60W adapter will generally allow you to operate the MacBook Pro without draining the battery, it may not also increase the available the charge. If the MacBook Pro is sleeping or powered off, the 60W adapter will increase the available charge.

Incidentally, some MacBook owners have found that they prefer 85W MacBook Pro adapters to the standard 60W adapters included with their systems. Though larger, the 85W unit does not (in some cases) get as hot as the 60W adapter, and might not generate some of the buzzing noises associated with the 60W unit. Note, however, that the 85W adapter will not charge a MacBook any faster than the 60W adapter.

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