EV Battery Warranty by Manufacturer: UK Comparison (2026)

The industry standard, and why it exists

The pattern most manufacturers follow is 8 years or 100,000 miles, whichever comes first, with a guarantee that the battery will still hold at least 70% of its original capacity at the end of that period. That 70% figure has become the industry benchmark, though it's worth understanding it's a floor rather than an expectation. Most batteries comfortably beat it.

Real-world data backs that up. A 2025 to 26 analysis of more than 22,700 vehicles found average degradation of around 2.3% per year, which projects to roughly 81.6% capacity remaining after eight years, comfortably above the warranty threshold. A separate UK study of over 8,000 cars and vans found older vehicles retained a median 85% of their capacity, with even very high-mileage examples rarely getting near their warranty trigger.

In other words: the warranty exists to catch the rare failure, not the normal outcome.

Two different warranties, often confused

This trips up a lot of buyers, so it's worth separating clearly:

The defect warranty covers manufacturing faults and workmanship, a cell failure, a duff module, a BMS fault. If the battery breaks, this is the cover that applies.

The capacity warranty covers excessive degradation. It only pays out if the pack drops below the stated threshold (usually 70%) within both the time and mileage limits. Crucially, this means a battery sitting at 75% when the trigger is 70% has no claim. It's degraded badly, but not badly enough. That gap is one of the most important things a used buyer can understand, and it's the reason knowing a car's actual State of Health matters more than knowing it's "still under warranty."

Comparison by brand

Figures are indicative for the UK market and vary by model year and variant. Always verify against the specific vehicle's warranty booklet or VIN.

What "8 years" actually means when you're buying used

The clock starts at first registration, not at your purchase. A 2019 EV bought in 2026 has around one year of battery warranty left, not eight. And because the limit is "whichever comes first," a high-mileage car can run out of cover long before the calendar does. An EV that's done 100,000 miles in four years has no battery warranty left at all.

This is why remaining warranty is one of the figures our check reports directly: it's a genuine, quantifiable part of what you're buying, and it should be reflected in the price you pay.

Which brands offer the strongest cover

On paper, Lexus offers the most generous terms in the UK, though the ten-year cover is conditional on keeping up annual health checks. Beyond that, the mainstream brands cluster tightly around 8 years and 100,000 miles, so the differences that actually matter tend to be in the details: transferability, the capacity threshold, and what's excluded, rather than the headline numbers.

MG is the notable outlier on the shorter side, and that's worth pricing in when comparing an MG4 against, say, an ID.3 of similar age.