Electric
Buying a used EV: how to check battery health (SoH)
Key takeaways
- SoH is the share of original battery capacity still usable; it says nothing about the technical condition of the pack.
- A SoH read from the car's own system is an estimate. An independent battery test typically costs around €100.
- On average a battery loses 2.3% of capacity per year; frequent fast charging above 100 kW speeds that up (Geotab).
- Battery warranty is often 8 years or 160,000 km with a floor of around 70% SoH; check each brand's conditions.
What is the SoH of an EV battery?
SoH (State of Health) is the percentage of the battery's original capacity that is still usable. A battery with a SoH of 90% stores 90% of the energy it could hold when new. Range drops roughly in proportion. See our glossary for more on SoH.
SoH only describes capacity, not the technical condition of the battery pack. A high SoH does not predict when a battery will fail, EV Update reported in October 2026, based on interviews with the battery testers Aviloo and EV Clinic. Problems with cells, cooling, insulation or electronics do not always show up in a single percentage. A good battery report therefore also looks at cell voltages, imbalance between cells and fault codes.
How do you get a reliable battery report?
There are roughly three routes: read the SoH from the car's battery management system (BMS), have an independent battery test done, or book a pre-purchase inspection that includes a battery test. An independent test typically costs around €100, according to viaBOVAG. Always ask how and when the SoH was measured.
| Method | How it works | Pro | Con |
|---|---|---|---|
| BMS readout | Dealer or garage reads the value from the car | Fast, often available at a dealer | An estimate, the margin can be large |
| Short test (flash test) | Measures cell voltages and compares cells | Fast, shows imbalance between cells | Can miss some defects |
| Extended driving test | Battery is discharged over much of its range while driving | Measures the real usable energy | Takes more time |
| Inspection with battery test | Inspector tests the battery as part of the check | Whole car checked in one go | Not every inspector tests batteries |
Aviloo puts the margin on Volkswagen's BMS value at 10 percentage points, according to EV Update. A SoH figure the seller reads out is a first indication, not proof. Choose a test with a certificate that states the method and the date. Our page on the aankoopkeuring (pre-purchase inspection) shows which inspectors offer a battery test, and the guide booking a pre-purchase inspection walks you through it.
What SoH is normal for an EV's age?
On average an EV battery loses 2.3% of its capacity per year, according to a Geotab analysis of more than 22,700 electric cars (April 2026). Cars that frequently fast-charge above 100 kW lose about 3.0% a year; cars that rarely fast-charge about 1.5%. So always judge SoH together with age, mileage and charging habits.
| Age | Average (2.3% a year) | Frequent fast charging (3.0%) | Little fast charging (1.5%) |
|---|---|---|---|
| 2 years | c. 95% | c. 94% | c. 97% |
| 4 years | c. 91% | c. 88% | c. 94% |
| 6 years | c. 86% | c. 82% | c. 91% |
| 8 years | c. 82% | c. 76% | c. 88% |
This is a worked example in which we extended the average annual loss in a straight line. It is not a standard: model, climate and use make a big difference, and Geotab found batteries in hot climates degrade slightly faster. viaBOVAG gives a practical example: a six-year-old car with 150,000 km and 86% SoH is fine, but a two-year-old, low-mileage car at 85% is a reason to ask questions.
What warranty covers the battery of a used EV?
Manufacturers often give 8 years or 160,000 km of battery warranty, with a floor of around 70% SoH, according to viaBOVAG. If capacity drops below that within the term, the manufacturer repairs or replaces the battery under its conditions. The term usually runs from first delivery or registration, not from when you buy the car.
Check each brand's conditions, because they differ. Ask whether the warranty transfers to a new owner and whether it comes with requirements, such as servicing on schedule. On an EV that is seven years old or close to 160,000 km, the battery warranty is often nearly over. A recent, good battery test then matters even more. If you are planning to take the car abroad later, also ask whether the warranty is valid outside the Netherlands.
What should you ask the seller of a used EV?
Ask for a recent battery report, charging habits, the remaining battery warranty and the service history. A seller who is open about the battery makes the purchase easier. If the seller refuses an independent test or inspection, the ANWB's advice is to keep looking.
- Is there a battery report, how recent is it and which method was used?
- How was the car usually charged: at home, at public chargers or mostly on fast chargers?
- When does the battery warranty end, and how many kilometres are left on it?
- Have all recalls and software updates been carried out?
- What is the winter range, and does the car have a heat pump?
- Are the charging cables and any adapters included?
Take the inspection checklist to the viewing so you don't miss anything.
What does SoH mean for the price?
A lower SoH means less range, which pushes the price down. A certified good SoH makes a used EV more attractive to buyers and can support its trade-in value, viaBOVAG writes. For sellers, a battery test before listing is therefore often worth it.
Selling an EV yourself? Put the SoH, the test date and the method in your ad, and show the certificate at the viewing. That removes a major doubt. Without a report, many buyers will simply offer less to be on the safe side.
More transparency is coming for new batteries. Under the EU Battery Regulation, EV batteries placed on the market from 18 February 2027 must have a digital battery passport that includes SoH information. For existing used cars, a separate test remains necessary. Planning to buy a used EV soon? Keep an eye on the used-EV subsidy: it has been announced, but is not open yet.
Frequently asked questions
What is a normal SoH after four years?
Around 91%, based on the average capacity loss of 2.3% a year that Geotab found in 2026. With a lot of fast charging it can be lower, with mostly home charging higher. Always judge SoH together with mileage and charging habits, and get an independent battery test if you are in doubt.
How long is the warranty on an EV battery?
Often 8 years or 160,000 km, with a floor of around 70% SoH, according to viaBOVAG. Exact conditions differ by brand. The term usually runs from first delivery or registration, not from your purchase. Also ask whether the warranty transfers to a new owner and whether any servicing conditions apply.
Is the SoH shown by the car itself reliable?
Not entirely. The value from the battery management system (BMS) is an estimate. Aviloo cites a margin of 10 percentage points for Volkswagen, EV Update reports. Use it as a first indication and, if in doubt, get an independent battery test with a certificate that states the method and date.
How much does a battery test cost?
Around €100 for an independent battery test, according to viaBOVAG. A full pre-purchase inspection costs more: the ANWB quotes €150 to €350 for a normal car. Not every inspector tests the battery, so ask before you book. For a seller, a recent test is often a worthwhile investment.
Does fast charging make a battery lose capacity faster?
Yes, on average. According to Geotab, cars that frequently fast-charge above 100 kW lose about 3.0% a year, against about 1.5% for cars that rarely fast-charge. A hot climate also speeds up degradation slightly. So ask the seller how the car was usually charged before you decide.
Can a seller refuse a battery test?
Yes, but treat it as a reason to keep looking. The ANWB advises moving on if a seller refuses an inspection. On an electric car the battery is the most expensive component, so buying without a reliable battery report means taking on a big risk.
Sources
Written by
Redactie Sell Your Car · Editorial team
Our editors write about buying, selling and the rules around used cars in the Netherlands. We check amounts and rules at the source: RDW, Belastingdienst, RVO, BOVAG and ANWB.
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