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keeper

macrumors 6502a
Original poster
Apr 23, 2008
528
307
Hi All

Do MagSafe adapters power off when not required to charge the battery or do they use 85w all the time?

UK power costs have shot up, so i now only use mine when required to reduce cost.

Cheers Phil
 
I believe as long as the charger is plugged into the wall it will be drawing electricity whether the device is plugged in or turned on. I'm not too sure if the whole 85W is being pulled but it is generally advised that to reduce power consumption when you are not using electronics, unplug their plugs from the wall.
 
I believe as long as the charger is plugged into the wall it will be drawing electricity whether the device is plugged in or turned on. I'm not too sure if the whole 85W is being pulled but it is generally advised that to reduce power consumption when you are not using electronics, unplug their plugs from the wall.

You are correct. It wont be drawing 85W, but it will be drawing minimal current, know as "Parasitic draw". Its nothing to worry about with something as small as an 85W power source.:cool:
 
85W refers to its rated power output under maximum load. Except under extreme circumstances (max CPU utilization, all fans running, optical drive spinning at max speed), you won't see the adapter drawing all 85W.

This is same in principle to the 1,000W supply in the Mac Pro. Imagine the power bill if that guy was continuously drawing 1kW....
 
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