State of Health, or SoH, shows how much of its original capacity the battery of an electric car or plug-in hybrid still has. An SoH of 90% means the battery can still store 90% of what it could when new. Every battery loses capacity through use and age; how fast depends on things like charging habits, mileage and climate.
Why it matters when buying or selling
- Range: a lower SoH means less range than the car's WLTP figure from when it was new.
- Value: the battery is one of the most expensive parts of an EV. A good SoH supports your asking price; a low SoH is a reason to negotiate.
- Measuring: have the SoH tested, for example at a dealer or during a pre-purchase inspection that includes a battery test. Ask for a recent battery report.
- Warranty: many manufacturers give a separate battery warranty with a minimum SoH. Check the term and the percentage in the warranty conditions.
- Seller: add a recent battery report to your listing and state the SoH. Use the listing score to see how complete your ad is.