An electric car has fewer wear parts than a combustion car: no oil changes, no timing belt, no clutch, and regenerative braking spares the brakes. That makes one component all the more important when buying used: the battery. It determines range, charging behaviour and a large part of the residual value. The following checklist helps you assess a vehicle realistically.
Battery health: SoH and battery certificate
The state of health (SoH) indicates how much of the original capacity is still usable. A value of 90 per cent means that the battery has lost around a tenth of its capacity. The on-board computer alone is of little help: many vehicles do not display the SoH directly, and the remaining range shown depends heavily on driving style and temperature.
A battery certificate is more reliable. Testing organisations, workshops and specialist providers read data from the battery management system or take measurements during a test drive. Reputable dealers present a current certificate; when buying privately, it is worth agreeing on a test before signing the contract. For new traction batteries, the EU Battery Regulation will require a digital battery passport in future. For today’s used cars, the certificate remains the most important tool.
Check the battery warranty
Many manufacturers give a separate warranty on the traction battery, often for 8 years or 160,000 kilometres. It usually applies if capacity falls below a minimum threshold within this period, often around 70 per cent. The terms differ by manufacturer and model year. Things to clarify: how much warranty time remains, whether it transfers to the new owner, and whether service records or installed updates are a requirement.
Charging and equipment
- AC charging power: the on-board charger determines how quickly the car charges at a wallbox. Single-phase or two-phase chargers take much longer than three-phase ones with 11 kW.
- DC charging power: it is not just the peak value that counts, but the charging curve, in other words how long the car maintains high power.
- Connector: CCS is the standard in Europe. Some older models use other systems, for which there are fewer rapid chargers.
- Heat pump: it heats far more efficiently in winter than a pure resistance heater, preserving range. On many models it was only available at extra cost.
- Charging cables: check whether a Type 2 cable for public charging stations and, where applicable, a portable charger for the household socket are included.
Tyres and suspension also deserve attention: electric cars are usually heavier and have high torque, which can wear tyres faster. It is also worth checking the 12-volt battery. In an electric car, too, it powers the on-board electronics, and if it is weak it can prevent the vehicle from starting.
Software and accounts
The software version matters, as does whether all available updates have been installed. Updates can improve charging behaviour, efficiency and driver assistance systems. Just as important: the previous owner must remove the vehicle from their manufacturer account and app, otherwise they may remain connected to its location and remote functions. You should also clarify whether connected services transfer with the vehicle or have to be booked again.
Test drive with rapid charging
The most telling test is a longer drive with a stop at a rapid charger. Ideally, the battery will be warmed up and fairly empty, at around 20 per cent. That shows what power the car reaches and how long it maintains it. If it stays well below the manufacturer’s figures despite a warm battery, this may indicate throttling or a weakened battery. Consumption, climate control and trouble-free starting at the wallbox are also worth checking. The range simulator shows how much range is realistic under various conditions. Background on cell chemistry can be found in the article LFP or NMC.
Range simulatorHow speed, temperature and a heat pump change the range.Record the battery certificate, warranty terms and software version in the purchase contract. That creates clarity if defects in the battery appear later.
Frequently asked questions
At what SoH value should I be cautious?
There is no fixed limit. What matters is age, mileage and whether the remaining range suits your own needs. If the value is close to the manufacturer’s warranty threshold, take a close look at the warranty terms.
Does the battery warranty also apply to the second owner?
In many cases yes, because it is tied to the vehicle. The exact terms are set out in the manufacturer’s warranty documents and should be checked before buying.
Does a used electric car need a special inspection?
Maintenance is usually simpler than with a combustion car. Manufacturers nevertheless prescribe intervals, for example for brake fluid, air conditioning and the battery cooling circuit. A complete service history can be important for the warranty.