EV·Store assistant
Hello! Questions about battery health, price, or financing — ask me anything.
The percentage on every car page isn't a guess — here's what State of Health actually is and how we get the number.
State of Health (SOH) is a percentage that shows how much of a battery's original, factory-new capacity it can still hold. A battery at 100% SOH holds as much charge today as it did when new; a battery at 80% SOH can only hold about 80% of that original amount, even though it might charge and discharge normally otherwise. It's not the same thing as the charge level shown on a dashboard (that's how full the tank is right now) — SOH is about how big the tank itself has gotten to be.
Every SOH percentage on our site comes from an independent battery diagnostic tool, run on that specific car — not a number we assume from the car's age or mileage, and not a manufacturer average applied across every unit of the same model. Two examples of the same model with the same mileage can have meaningfully different SOH depending on how they were charged and driven by their previous owner, which is exactly why we test each car individually rather than publishing a single figure for a whole model.
Where we have a diagnostic report on file, ask to see the underlying test data when you come look at the car — you, or a mechanic you trust, can check it yourself instead of taking our word for the summary number.
We use the same rough bands across the site:
These bands are a starting guide, not a hard cutoff — the right number for you depends on how far you actually drive day to day.
We don't estimate SOH from a car's age or mileage when we don't have a real test, and we don't round a borderline number up to make a car look better. If a car hasn't been tested yet, its page says so plainly instead of guessing — the same information gap you'd see if you asked us in person.
On a petrol car, mileage and age tell you most of what you need to know about remaining life. On an EV, the battery is the single most expensive component to replace, and its condition doesn't track mileage in a simple straight line — which is why we treat SOH as the headline number for every used EV we sell, not a footnote.