Charging problem on Pre facelift MG5

[mattlfr]

I have owned my 22 MG5 EV for about 18 months. I have a Zappi 2 and Octopus Intelligent Go, and charge overnight on a smart schedule. Up until a few weeks ago, everything worked fine, then I started finding the car had only partially charged overnight.

On checking the Zappi, I realised that it had never updated the firmware, and was running the 2022 version, so I updated this and it seemed fine for the first day. Then the problems came back again.

Octopus app:
Smart charging turned on
Zappi is paired ok

Zappi app:
Set on Eco+

It nearly always starts to charge ok, and then by the following morning I find one of these:

Zappi reads ‘Charge complete’ although the car is nowhere near full. This is the commonest one.

Zappi reads ‘EV disconnected’ although car is plugged in.

Zappi reads ‘RCD check’ with a blue light and gets stuck like this, needing a reset at the power switch.

Zappi reads ‘RCD tripped’ with a red light, needing a reset at the power switch.

I have only had the RCD errors once.

I even tried doing away with the smart charging and just setting a schedule to charge during the off peak period, but I still got the ‘Charge complete’ error after an hour.

I can see no damage to the cable, and have always treated it with care. The Zappi is only 18 months old.

I have tried disconnecting the 12v battery to reset the car.

I am waiting to hear back from Myenergi as they initially said the first two errors were coming from the car and that this is a common problem with MG5s but the RCD errors suggest a problem with the Zappi. MG have said they would need to have the car in to make any assessment but can’t see it for at least 2 weeks.

I have searched and seen a few similar issues on here, but have not found a solution specifically with the pre facelift MG5. I am fed up with getting up in the middle of the night to mess about with it and having to bump charge at the higher price during the day! Anyone got anything ideas?

Thanks, Matt

 

[Everest]

Do you have a granny charger to test it from?
Does it work at an AC slow charger at a supermarket?

Doing those tests should help pinpoint whether the issue is with the car vs. your Zappi (or OE).

 

[mattlfr]

The granny charger works OK. Not tried another AC slow charger so will give that a go.

The problem is that these faults are all intermittent, so I guess they might appear on another charger if I did it for long enough.

 

[Everest]

The granny charger works OK. Not tried another AC slow charger so will give that a go.

Sounds like a good plan. Hopefully the car is OK if it works with the granny, unless the fault is specific to charging at a greater rate than the granny can provide.

Has anything else changed, especially with regard to your power supply, that coincided with the failures? e.g. have you had any electrical work done, e.g. new circuits etc., or has the DNO changed a local low-voltage transformer, replaced overhead wires etc.?

 

[rpannell]

Do you have anything else turning on during the nighttime which, when combined with the 7KW charger, is dropping the voltage below that acceptable for the zappi - eg washing machine, home battery, hot water heater etc?

 

[mattlfr]

I've had no electrical work or any changes recently but I do run a dishwasher overnight. With the rest of the house shut down, I'd be surprised if that was causing a significant drop in power, but I could stop that for a week and see how that goes.

 

[Everest]

With the rest of the house shut down, I'd be surprised if that was causing a significant drop in power, but I could stop that for a week and see how that goes.

@rpannell was referring to voltage, rather than power. It can be an issue for some users (e.g. @Montego as detailed in the thread below). It could be that other households on the same phase as you have recently added EVSE and pulled your local voltage down.

As well as testing without dishwasher on, I'd suggest you could also:-
a) try using the Zappi during the day, esp. after lunch on a weekend, when traditionally network voltages are highest and
b) try running the Zappi at a lower charge current, e.g. 3 to 4kW, if it has that capability.

All of these will help narrow down the source of the problem.

Thread 'Lowest Declared Voltage Tolerance and Charging'

Dec 12, 2025

I recently learned that electricity network operators are legally required to maintain the voltage within a specific range. This range is defined as +10% and -6% of the 230V nominal voltage which results in an allowed voltage range of 216.2V to 253.0V.

To take advantage of the E.ON Next Drive tariff I charge my MG4 between the hours of midnight and 07:00 hours. I usually charge the car battery to 80% to maintain battery health. I program the session using the Pod-Point app, not the car. On three occasions my Pod-Point failed to achieve the programmed charge level during the charging...

• Montego
• distribution network operator eon next drive tariff ev charging low voltage mg mg4 pod-point voltage tolerance
• Replies: 13
• Forum: EV + Charger + Solar + Battery + Tariff Advice

• 

 

[mattlfr]

Thanks all, I will give these a go and see if I get anywhere.