Ask Different is a question and answer site for power users of Apple hardware and software. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I leave my iPhone charger plugged in all day. Does it draw current when I'm not charging my phone?

share|improve this question
up vote 0 down vote accepted

If the USB cord is not plugged into anything on the other end it should not be drawing any power that would be worth speaking of.

However if you are talking about the USB charger box that converts a normal power outlet to USB power to charge your iPhone then yes, those do draw power as long as they are plugged in. You can tell as they get very warm even when not charging.

It is recommended to unplug any electronics when they are not in use to save power, however I do not do this unless I am not using it for a few days.

share|improve this answer
"Very warm" when not charging? I know they draw a little power, but I've never witnessed the little white box getting warm when there's not actually a load attached to it. I'd expect a charger that gets warm with no load has a problem of some kind. When there's a load is another matter, of course. – zigg Aug 2 '13 at 14:24

Yes it does, it has a transformer in it where the current passes true at all time as long it is plugged in to a socket.

Since it is in idle mode it might draw some micro amps.

To put it in prospective 1 Amp = 1000 mA

and 1 Milli Amp = 1000 uA (micro amps)

So it is drawing 10-6 Amps :) (one millionths of a Amp)

So from consumption it is to small to even consider.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.