Inspecting a used electric car: the complete checklist

Some things you can check yourself at the viewing. Others need diagnostic equipment and can only be done in a workshop. Here are both, in the order worth doing them.

At the viewing, on your own

1. Start the car from cold if you can. Look for warning lights: “check hybrid system”, a yellow triangle, the battery or charging symbol.
2. Charge from a socket or wallbox, not only at a fast charger. If the car only charges on DC, the on-board charger may have a problem.
3. Check the charging port: burnt or blackened pins, the flap and the latch that locks the cable.
4. Listen to the fans and pumps after a drive. A very loud fan on a hybrid can mean the battery is running hot.
5. Look under the car, especially at the battery casing. Dents, deformation or rust on the casing call for a serious check.
6. Try the brakes and listen to the wheels. On EVs, the rear discs often rust because they are used so little.
7. Ask for the paperwork: service history, invoices for battery work and, on some Renaults, proof that the battery belongs to the car.

In the workshop, with equipment

• Battery state of health (SoH) read from the control unit, plus the voltage of each cell group and the differences between them.
• Load test: how the voltages behave under acceleration and regenerative braking.
• Fault history from every module, including recently cleared faults.
• Insulation resistance of the high-voltage system.
• Cooling circuits for the battery and inverter: level, pumps, fans.
• AC and DC charging, and the DC-DC converter that keeps the 12 V battery charged.

Warning signs

• The seller refuses a workshop inspection.
• Large differences between cells or modules, even if the displayed percentage looks fine.
• Range well below what it should be for the car’s age and mileage.
• Signs of water or repairs around the battery.

If you are wondering what matters before you even get to a viewing, read buying a used electric car.