03-12-2012, 04:04 AM
Sort of. You can use an 85W Magsafe adapter with any Magsafe laptop.
You can use a 65W Magsafe adapter with any Magsafe laptop, however, it might be overtaxed on a 15" or 17" and the 15/17 may not be able to charge the battery during heavy processing, or it will charge slower and it will not boot with a completely dead battery and a 65W adapter until the battery is charged up again.
You can use a 45W (from the Air) on a 15" (which I've done for short periods of time) and presumably a 17", but the same caveats from the 65W adapter apply. Also overtaxing a smaller adapter might shorten the lifespan of the adapter itself.
You can use a 65W Magsafe adapter with any Magsafe laptop, however, it might be overtaxed on a 15" or 17" and the 15/17 may not be able to charge the battery during heavy processing, or it will charge slower and it will not boot with a completely dead battery and a 65W adapter until the battery is charged up again.
You can use a 45W (from the Air) on a 15" (which I've done for short periods of time) and presumably a 17", but the same caveats from the 65W adapter apply. Also overtaxing a smaller adapter might shorten the lifespan of the adapter itself.