It's not a Zappi issue. Zappi diverts excess solar to the car by telling the car via the pilot signal how much energy can be taken. The minimum level is 1.4kW which is set by the EVSE standards. If your excess energy drops below 1.4kW because of cloud obstructing the sun, additional house loads etc, Zappi correctly tells the car not to take any power. When spare energy becomes available again, the pilot signal is changed again and the EV informed it can start to take power again. It seems that MG in their wisdom after a certain number of charge / dont charge cycles stop the charge completely and wont resume when power is available. Many people say it doesnt happen to theirs but maybe they havent been charging at a time where the spare energy is hovering around the 1.4kW mark. It does help to reduce the likelyhood of the problem if you adjust the charge delay on the Zappi so that the threshold has to be exceeded or dropped below for 'x' seconds before Zappi will instruct the car to stop / start the charge, the downside is a little bit of grid import / export will take place for those 'x' seconds.