For the first few weeks the 10 Amp AC charger supplied with the car did display 100% at the end of charging.
Later on I did get an error message “waiting for car signal”. When I open the car door charging/balancing resume till the charger display 100%.
I took the car back for service on four occasions. I was given some other chargers and loaned some other cars, all with the same problems. MG denies this is a problem.
I have filed a complaint with fair trading but the person handling this had no knowledge or understanding of the battery management system of an electrical vehicle.
The solution offered was a new charger. It did not display the state of charge at the end of charging (100%) but two green lights. Upon opening the car door charging did resume.
I requested the return of the original charger but was offered a new MG branded charger with no SOC (state of charge display) but no specs were available. I got my old charger back and I am convinced that the MG ZS EV has a glitch with their BMS. The new charger instructions state that the charger must be disconnected from the power supply before the car is opened. That insures that charging cannot resume.
A new upgraded model of the MG ZS EV is available at the end of the year but they have no intention of fixing the problem with the older model and are offloading it on the Australian market
The car interrupts charging during the equalization. It does not communicate to the charger the final state of charge of the battery.
Balancing resumes when the car is woken up.
Battery balancing improves the available capacity of a battery pack with multiple cells and increases each cell’s longevity. The fact that there is a glitch in this system may affect the range of the car and the longevity of the battery. The battery performance is only as good as the worst cell in the pack.
I had the same problem with two other display cars of the same model. The “proposed fix” from MG is to change the charger when the manufacturer of the charger deny that there is anything wrong with the charger.
If it occurs regularly, it might be worth testing with another charger to see if this fixes the problem. Ask MG if they have one you can test with. This then allows you to work out if it is the charger, if the car fully charges without any issue.
If the problem persists, it could be an inherent fault with all chargers of that make and model or a problem with the car battery system.
Maybe then try a different make and model charger as there could be an incapability issue with the car… which isn’t necessarily the car or charger issue. As MG supplied the charger with the car, MG needs to then resolve.
It seems like an issue that the BMS is not outside the ‘sleep’ timer for the Vehicle system. So when the rest of the vehicle goes to sleep to save energy the BMS is also not functioning. A line of code or two somewhere that needs tweaking to allow the BMS to function at all times it appears, that is a manufacturing issue and obviously the firmware needs updating to correct the issue.
