V90 T8 charging question

[JonboyP]

Greetings.

I'm using a granny cable (genuine Volvo branded item) and a wifi socket on a timer to charge overnight on a cheap electricity rate.

I'm seeing more and more charge failures.

With the electric power off I am plugging the plug into the car and locking it with the remote and after a few seconds there is a mechanical sound which I presume is some sort of locking pin because I then can't pull the plug away from the car (it's supposed to do that, I know). I then switch the electric on and then I'm getting a red light instead of green.

So I unlock the car, remove and reinsert the plug into the car, hearing the mechanical sound and after a few tries I get a green light instead of red, and the car charges as it should.

Any pointers gratefully received.