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How to check a used MG4 battery: size, warranty, recalls and health (UK)

Published 2026-11-08 · Last updated 2026-11-08 · based on 29 sourced MG4 data points and 35 sources

The MG4 is MG's electric hatchback, sold in the UK from late 2022 with either an LFP or an NMC battery depending on version and model year. On the 16 UK dealer AVILOO certificates that print an independent SoH, results ranged from 94.1%–99.4%. The bigger questions on a used MG4 are which pack it has (a 64 kWh Long Range changed from NMC to LFP in MY26), how MG's 7-year vehicle cover differs from the 8-year / 70% high-voltage battery terms, and how an independent test compares with other MG4s. This guide covers each check.

All figures with method and date: used MG4 battery data. Comparing the two chemistries in more detail: MG4 LFP vs NMC. Going to a viewing? Make a printable list of questions for the seller. Sister MG guides: MG5 EV battery check · MG ZS EV battery check. China-built context: Chinese EVs battery guide.

1. Identify the battery

EV Database listings, checked 2026-11-08 (MY22-25) and 2026-11-08 (MY26). MY22-25 cars are listed as no longer for sale new.

• The 64 kWh Long Range changed chemistry in MY26. The 2022–2025 Long Range uses NMC cells; the Premium Long Range sold from February 2026 is listed with the same 64.0 / 61.7 kWh size but LFP cells (EV Database). The MY26 XPOWER stays NMC at that size (EV Database). Check the first-registration date and ask an MG dealer to confirm the battery from the VIN – the badge alone is not enough.
• Go by the battery size on the V5C, the advert or a test certificate, then confirm the model year. Trim names (SE, Trophy, Exclusive) don't tell you the chemistry.
• Don't confuse this car with the MG4 Urban: ADAC describes it as a separate car on a different platform with a 53.8 kWh LFP battery (ADAC).
• LFP and NMC packs age differently, so compare a test result only with cars that have the same battery. We unpack the (still thin) MG4 comparison on MG4 LFP vs NMC, and list other models on which used EVs have an LFP battery.
• AVILOO lists FLASH-test support for the MG4 51, 64 and 77 kWh packs (AVILOO GmbH).

2. Check the recalls

When we checked DVSA's recall file (DVSA; MG4 rows re-checked 2026-11-08 against the 4 November 2026 download), it listed no high-voltage battery recall for the MG4. The only MG4 row in the file is:

On an early 2022 car, ask whether that software update was done. The file can lag behind new campaigns, so this isn't proof that a car is clear. At a viewing, still run the free GOV.UK recall check on the registration (GOV.UK) and ask an MG retailer to check the VIN.

3. Check the battery warranty

MG UK (warranty statement for cars registered on/after 1 Sep 2019, online version dated 1 Jan 2025): vehicle 7 years / 80,000 miles; the lithium-ion high-voltage battery is listed at 96 months / 100,000 miles, and a capacity drop below 70% of the original value is treated as excessive loss (repaired, or the battery replaced with a new or remanufactured one). Private-hire/taxi EVs have a shorter vehicle warranty, but the statement says the HV battery "in all cases" has 8 years / 100,000 miles from 1 Jan 2025. Confirm the cover for the specific car (VIN, registration date) with MG. (MG Motor UK, checked 2026-10-30)

• Don't confuse the vehicle warranty (7 years / 80,000 miles) with the high-voltage battery cover (8 years / 100,000 miles, below 70%). The battery terms are the ones that matter for SoH.
• The capacity check is done by an authorised MG repairer. If capacity is below 70%, MG treats it as excessive loss and repairs or replaces the battery with a new or remanufactured one (MG Motor UK).
• MG says the warranty transfers to each new owner while it lasts, and that a claim can be rejected if the high-voltage battery has been opened by anyone other than an MG authorised New Energy repairer, or if service intervals weren't followed. Ask for the service history.
• Private-hire and taxi-registered EVs have a shorter vehicle warranty, but from 1 January 2025 MG says the HV battery is covered for 8 years or 100,000 miles in all cases. Ask how the car was registered.
• The first UK MG4s were listed from October 2022, so private cars stay inside the 8-year limit until at least October 2030 unless they pass 100,000 miles. Our battery warranty checker works out the time and mileage left (UK terms (statement dated 1 Jan 2025): 8 years / 100,000 miles, below 70%). How MG compares with other brands: used EV battery warranty in the UK.

4. Get a battery reading you can trust

• Do a full slow (AC) charge before any reading: MG says a full slow charge is the only way for the battery to reach its balanced "equalisation" state, and the car shows "Please Slow-charge the Vehicle" if one has not been done for a while. (MG Motor Europe)
• MG service inspection reports can include an SoH figure, and OBD apps can read the car's own value – but owners report these car-reported figures can move by several points between services (e.g. 99% → 100% → 95% on one car), so treat them as a guide. (MGEVs.com owner forum)
• Ask for an independent battery test. AVILOO lists FLASH-test support for the MG4 51, 64 and 77 kWh packs shown above, so a dealer certificate or a mobile tester can give an SoH figure you can compare with the results on this page. (AVILOO GmbH)
• On the 16 UK AVILOO certificates that also print the car's own BMS figure, the two differed by up to about 3.6 points. The car's own figure was higher on 10, lower on 6 and the same on 0.
• One UK report for a 51 kWh LFP car printed only the car's own figure (92.5%) and an AVILOO score of 94/100, not a separate AVILOO SoH (Car360). If you're paying for a test, check that the report gives an SoH percentage.
• An independent test (AVILOO GmbH) gives a figure you can compare with the table below. UK options and prices: UK battery test comparison. To read the result: certificate guide.

5. Compare the result with other MG4s

• No AVILOO median is published for the MG4 itself. Every figure below is a single car (n=1).
• The 16 UK dealer AVILOO certificates that print an independent SoH (9,233–67,475 km, ≈5,737–41,927 miles) read 94.1%–99.4%. Of those, 13 were 64 kWh NMC cars (94.2%–99.4%) and 3 were 51 kWh LFP cars (94.1%–95.0%). The lowest independent UK result, 94.1%, was at 26,361 miles; the highest-mileage UK car (41,927 miles) had 96.0%.
• 3 other independent AVILOO certificates (Slovakia, France and one Australian LFP car, which is a hot climate and not UK conditions) read 94.1%–95.5%.
• 9 owner-reported readings (MG service reports and OBD or app figures from German and UK owner forums) ranged 91.0%–99.0%. These are not independent tests – treat them as examples only. Owners note that MG's own figure can move between services (MGEVs.com owner forum).
• A UK independent result clearly below about 94.1% at similar mileage is worth questioning. Get the car tested again or ask an MG New Energy repairer to check it.
• As a rule of thumb for all EVs, ADAC expects at least 92% at 50,000 km, 88% at 100,000 km, 84% at 150,000 km, 80% at 200,000 km (ADAC).
• We do not have enough like-for-like MG4 data to say which chemistry ages better. That comparison, and what larger Tesla and laboratory studies show, is on MG4 LFP vs NMC.
• Compare the MG4 with other MG models on the battery degradation chart, or get a quick estimate with the battery health estimator.

Every MG4 single-car result we have (n=1 each)

16 UK dealer AVILOO certificates with an independent SoH, 3 other independent AVILOO certificates, 1 UK certificate that printed only the car's own figure, and 9 owner-reported readings. Single cars show the spread, not an average. Owner-app and service-report rows are not independent tests. Every row is also on the MG4 data page.

6. Battery replacement cost (UK)

We have not found a verifiable, dated UK price for a new MG4 battery, from MG or an independent specialist, so we don't quote one. Inside 8 years and 100,000 miles a battery that falls below 70% is covered under MG UK's high-voltage terms (MG Motor UK). For an out-of-warranty car, get a written quote from an authorised MG New Energy repairer before you buy. General UK figures are in our EV battery replacement cost guide.

Also see: MG4 LFP vs NMC · which used EVs have an LFP battery · MG5 EV battery check · MG ZS EV battery check · used EV battery warranty (UK comparison) · Chinese EVs battery guide · general used-EV battery checklist · battery problem after buying: your rights (UK) · all models compared.

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