This question is def. not a duplicate of the ones linked. "Your Battery is Dead", I'm afraid, is not the solution.

Edit: The event did not happen with AC plugged in, it happened on battery. I then plugged in the AC in order to wake it. The battery is fine and does not need replacement.

So I woke my MBP from sleep, plugged in my iPhone and within a minute, computer put itself back to sleep. I plugged the AC in, woke it up and checked the logs. The offending message is the title of this Q.

My battery has gone through about 926 cycles, so not exactly dead. Couldn't for the life of me figure out what had happened, but I run Micro Snitch in the background, which happened to be telling me that a microphone had kept getting connected/disconnected.

Well, at that point, I quickly realized that the Apple Lightning to USB adapter I plugged in was faulty and constantly cycling on/off, thus throwing my machine into disarray, as Photos and iTunes are set to open automatically when my phone is attached.

I'm guessing that the algorithm used to determine "remaining charge" decided that if my laptop kept doing what it was doing, the battery would very quickly die, so it put itself to sleep.

Of course, I could be wrong.

My question is, does anyone know where I can look to verify this (or what) happened, exactly? 'Low Power Sleep' isn't exactly an error, so my guess is this would be logged as an ordinary event.

Here is current battery info:

  Charge Remaining (mAh):   4893
  Fully Charged:    No
  Charging: Yes
  Full Charge Capacity (mAh):   7426
  Cycle Count:  926
  Condition:    Normal
  Battery Installed:    Yes
  Amperage (mA):    3586
  Voltage (mV): 12436


  • @Allan I don’t think it’s a dupe. My battery is fine. I think it’s a result of my machine handling an iPhone being connected/disconnected every second. Possibly even more rapidly than say the iPhone “connected sound” can even indicate. For all I know, it could’ve been cycling 10+ times a second. – Dylan_Larkin Jan 29 '19 at 17:06
  • How did you determine that? – Allan Jan 29 '19 at 17:09
  • @Allan Micro Snitch was a tell. I then confirmed by looking at the battery icon on my iPhone to verify it was toggling between charging and not. – Dylan_Larkin Jan 29 '19 at 17:10
  • Not that it was cycling, but that this cycling somehow caused a feedback from the USB port back into the USB controller and ultimately into the power rail that's connected to the battery which, coincidentally is protected by diodes that limit current flow in only one direction? – Allan Jan 29 '19 at 17:12
  • The event in question happened almost instantaneously upon attaching my iPhone. Not saying there was a power surge of sorts, but that plugging my iPhone in results in a number of programs automatically opening and engaging in I/O ops. This repeated action is what I suspect caused the machine to calculate that it was low on power, thus going to sleep. I can’t confirm it, hence the question. I also suspect that I can reproduce it (not that I want to). – Dylan_Larkin Jan 29 '19 at 17:17

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