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Checking a used electric car's battery health

RegVerdict guide·7 min read·Reviewed 17 June 2026

What battery state of health means, what counts as healthy, and how to check it on a used electric car.

When you buy a used electric car, the battery is the single most important thing to get right. It is the most expensive component to replace, it sets the usable range, and it is the one part an MOT does not check. The good news is that battery health can be measured, so you do not have to guess.

What battery state of health means

State of health, often shown as SoH, is the battery's current usable capacity as a percentage of its capacity when new. A battery at 92 percent holds about 92 percent of its original energy, and so delivers about 92 percent of the original range. Batteries lose a little capacity over time and use, which is normal and gradual.

What counts as healthy

  • Expect gradual decline. Degradation is often around one to two percent of capacity a year, though it varies by model and use.
  • Compare like with like. A figure that is much lower than other cars of the same model, age and mileage is the thing to question, not a single number in isolation.
  • Think in range, not just percent. What matters is whether the remaining real-world range fits your journeys with margin to spare.

What affects how fast a battery ages

  • Heat, from hot climates or frequent fast charging, is the main accelerator of ageing.
  • Rapid charging, if it is the car's main diet rather than slower home charging, can add wear over time.
  • Sitting at very high or very low charge for long periods is harder on the battery than staying in the middle.
  • Mileage and age both play a part, but a high-mileage car that was charged gently can be healthier than a low-mileage one that was not.

How to check the battery before you buy

  1. Ask for a state of health figure and, ideally, a recent battery health certificate from a dealer or independent specialist.
  2. Charge the car, or ask the seller to, and compare the indicated full-charge range against the model's original figure.
  3. Check the battery warranty: the start date, the mileage limit, the capacity level it guarantees, and that it transfers to you.
  4. Look at the charging history and habits if known, and whether the car has its original charging cables.
  5. Run a normal history and MOT check on the rest of the car, because brakes, tyres and bodywork still matter.
The battery is separate from the rest of the checkA clean MOT and history tell you the car is roadworthy and that the mileage and ownership look right. On an EV you still need the battery state of health on top, because the MOT does not measure it.

Run a RegVerdict check on the registration for the MOT history, mileage record and a clear verdict on the car itself, then add a battery state of health figure or certificate before you commit. Our used car buying checklist covers the rest of the viewing.

Common questions
How do I check an electric car's battery health?
Ask the seller for a battery state of health figure, shown as a percentage of the original capacity. Some cars display it in a service menu, and independent specialists and many franchised dealers can run a state of health test that produces a certificate. Compare the real-world range the car shows when fully charged against its original figure, and check whether the battery is still inside its warranty.
What is a good battery health for a used EV?
There is no single pass mark, but as a rough guide many electric cars are still in the high 80s to mid 90s percent of original capacity after several years and normal mileage. A figure noticeably lower than other examples of the same age and mileage is worth investigating. What matters most is that the remaining range still suits your needs.
How long do EV batteries last?
Most modern electric car batteries are expected to outlast the rest of the car, degrading gradually rather than failing suddenly. Typical degradation is often in the region of one to two percent of capacity a year, though it varies with heat, mileage, how often the car is rapid-charged and how it is stored. Outright battery failure on a mainstream EV is uncommon.
Does a used EV battery come with a warranty?
Usually. Many manufacturers warrant the traction battery for around eight years or roughly 100,000 miles, often against capacity dropping below a stated level such as 70 percent. These warranties commonly transfer to later owners, so check the start date, the mileage limit and the exact terms for the specific car.
Does the MOT check an EV battery?
No. The MOT checks roadworthiness, lighting, brakes, tyres and similar items. It does not measure the health of the traction battery, which is the most valuable component in an electric car. That is why a separate battery check matters when buying used.

Check before you commit

Enter a registration for an instant, evidenced verdict on mileage, MOT history and known faults.

Keep reading
Write-off categoriesWhat Cat A, B, S and N actually mean, whether the car is safe to buy, and how hard to negotiate.Car clockingHow odometer fraud works, the tell-tale signs, and how to check a mileage history for rollbacks.Outstanding financeWhy money still owed on a car can become your problem, and how to protect yourself before you pay.

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