A hard reboot.

Or a kick in the wot sits.
The gov never turns it off so all its little Rams get overloaded and the battery goes flat trying to sort them out according to the techie man from Apple.
Turning it off allows all the Rams to relax and everything is cool.
Never mind if that is techie b*ll*x, it worked and there was no charge.
Now need to get my MacBook looked at because it is embarrassingly slow..........