iPhone cuts out constantly when charging on a Mac

bp1000

macrumors 65816
Original poster
Jul 7, 2011
1,334
47
I charge my iPhone on my computer via USB, on both my iMac and MacBook Pro.

Problem is, it won't stay charging. It will just stop charging and then immediately start again, sometimes in quick succession, like 5-10 times one after the other, or once every 20-30 seconds like it's doing now as I write this post.

When it stops and starts, it vibrates, lights up the screen with the battery icon and switches off.

Drives me mad. It started with my iPhone 7+. Thought it was that, but it still does it on both machines with my iPhone 11.

Tried different USB ports and cables and with the latest OSX update, I decided to format and re-install the OS.

Any idea why this happens? my machines are 2013 to 2016. Maybe the USB power is too low?

P.s. annoyingly it asks me to trust this computer every time too.