It's pretty simple:

  1. If I turn off the phone's screen and then connect the wall charger, the power supply draws ~6W from the wall, and this doesn't change if I keep waiting.

  2. If I connect the wall charger and then turn off the phone's screen, the power supply draws ~10W, and I hear a very slightly audible high-pitched noise from the power supply the moment I turn off the screen.
    If I turn on the screen again, it goes back down to ~6W, but once it turns off it goes up again.

I have two questions:

  1. What is causing this?

  2. If it is intentional and not a bug, then what is the rationale for the cause? Is this well-known?

The ROM is CM11S 05Q.

(Yes, the charger & cable are the OEM's, and yes, I've actually measured the current.)

  • Yes 10 W is normal. In case 2, does the power supply in watts not reduce after turning the screen off . Please wait and observe.
    – beeshyams
    Commented May 16, 2016 at 8:59
  • @beeshyams: Well it's charged now, so it'll be a while before I can retry -- but I'm pretty sure when I charged it I didn't see it reduce until sometime after 90% (where I presume it had switched charging modes).
    – user541686
    Commented May 16, 2016 at 9:03
  • @beeshyams: I just tried it for 20 mins (~40% to ~70%); nothing went down on either end. The OPO Charging app reported 1800 mA average while the screen was off, and around 900 mA while it was on.
    – user541686
    Commented May 17, 2016 at 4:23
  • My bad. Interpreted it as screen being on in one case. As of now can't figure this. Will post if I can think through this
    – beeshyams
    Commented May 17, 2016 at 11:05
  • Can't think of any reason for this . Shot in the dark - try changing the power supply source. That noise makes it suspect but I can't see how that should affect on/ off power variation
    – beeshyams
    Commented May 17, 2016 at 12:18


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