Buying a used electric car: how to check battery health
Last updated: 19 June 2026
The battery is the most valuable part of a used EV. Learn how to assess its health, range and warranty before you buy.
Why the battery is everything
On an electric car, the battery represents a large share of the value and the cost of any future repair. A healthy battery makes a used EV a great buy; a degraded one can be a money pit.
1. Check the state of health (SoH)
Many EVs display a battery state of health or you can read it via the car's menus or a diagnostic app. Above ~90% is excellent; gradual decline is normal, but a sharp drop for the age and mileage is a concern.
2. Compare real range to the original
Fully charge the car (or check a recent full charge) and compare the indicated range to the model's original figure. A large gap suggests meaningful degradation.
3. Verify the battery warranty
Most makers warrant the battery for around 8 years or 160,000 km, often guaranteeing a minimum capacity. Confirm what remains and whether it transfers to you.
4. Ask about charging habits
Frequent rapid (DC) charging and routinely charging to 100% can accelerate wear. A car mostly home-charged to 80% is generally gentler on the battery.
5. Don't forget the rest of the car
EVs still have tyres, brakes, suspension, 12V battery and bodywork. Inspect them as you would any used car — and EVs can be heavy, so check tyre and brake wear carefully.
6. Get the numbers in writing
Ask for a battery health report or a diagnostic readout, and keep it with the sale. Document the car's condition with photos; a CarGuard AI inspection can screen the bodywork and overall condition before you commit.