MajorCommonElectrical

MG ZS: Gen 1 Battery Pack Capacity Degradation

Gen 1 Battery Pack Capacity Degradation is a common electrical fault on the MG ZS on the 2019–2022 cars, and we rate it major. Putting it right costs $4,000 to $12,000 at New Zealand independent workshop rates. Below is what goes wrong, the symptoms to notice on a test drive, where to look, and what to ask the seller before you hand over any money. It is one of 14 documented faults on the MG ZS.

Vehicle: MG ZS
Years: 2019–2022
Fuel: ev
Gearbox: auto
System: Electrical

This page covers the MG ZS as a model. Some faults only affect particular engines or build years — enter a plate below to narrow the list to one car.

All MG ZS faults14 documented faults on this model

What you are looking at

No photograph available

We do not hold a verified photograph for this fault yet. We would rather show none than show a picture of something else.

What goes wrong

The first-generation MG ZS EV (44.5 kWh CATL battery pack, 2019–2022) has documented accelerated capacity degradation in NZ and AU climates. Owners report 15–20% capacity loss by year 4–5 of ownership at 35,000–60,000 km. The BMS calibration in early units did not manage cell balancing adequately, compounding normal chemistry degradation. Replacement packs are expensive and availability through NZ and AU supply chains is limited.

What you would notice

Range displayed at 100% charge significantly below original 263 km WLTP
State-of-charge drops faster than expected in first and last 20% of charge
BMS cell imbalance warnings on instrument cluster
Reduced regenerative braking effectiveness

How to check it

Where to look. Under-floor high-voltage battery pack, full vehicle floor span

Request a battery health report from an EV diagnostics tool or MG dealer OBD scan.
Note the displayed range at 100% charge versus the 263 km WLTP original figure.
Check for any battery warnings in the service history.

What it costs to put right

$4,000 to $12,000 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

Ask the seller

“What range does the vehicle show at 100% charge today?”
“Has a formal battery health check been performed — what percentage was the result?”
“Any BMS or battery warning lights in the vehicle's history?”

Now check the MG ZS you are actually looking at

Everything above is true of the model, and it is free. What it does not tell you is whether THIS car has been looked after: its odometer history and whether the reading has ever gone backwards, whether there is still money owing on it, whether it has been reported stolen, how many owners it has had and what it is really worth today. That comes from the official records for that plate. Enter the plate for the free details, or get the full history and a market valuation from $13.49.

Not sure what you would be paying for? See what a full KickTyres check includes.

Where this comes from

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.

MG ZS buyer questions

Is gen 1 battery pack capacity degradation serious on a MG ZS?

We rate it major and common on the MG ZS. The first-generation MG ZS EV (44.5 kWh CATL battery pack, 2019–2022) has documented accelerated capacity degradation in NZ and AU climates. Owners report 15–20% capacity loss by year 4–5 of ownership at 35,000–60,000 km. The BMS calibration in early units did not manage cell balancing adequately, compounding normal chemistry degradation. Replacement packs are expensive and availability through NZ and AU supply chains is limited.

How much does it cost to fix on a MG ZS?

$4,000 to $12,000 at New Zealand independent workshop rates. That figure is for this job on its own. A car showing the symptoms on this page is usually worth either walking away from or negotiating down by at least the repair figure.

Which MG ZS years are affected?

Our research records this fault on the 2019–2022 MG ZS. Build dates move around, especially on imported cars, so treat the range as the years to look hardest at rather than a guarantee either way. The official records tell you the exact build and first registration date for the car in front of you.

How do I check for it before I buy?

Request a battery health report from an EV diagnostics tool or MG dealer OBD scan. Note the displayed range at 100% charge versus the 263 km WLTP original figure. Check for any battery warnings in the service history. Look here: Under-floor high-voltage battery pack, full vehicle floor span