How to read a battery health report like our technicians do

On a used gas car, you'd want the service records. On a used EV, one document outranks everything else: the battery health report. It tells you how much of the original pack is still there — and it's the difference between buying with confidence and buying on hope.

Every car on our floor comes with one. Here's how to read it, whether you're shopping with us or anywhere else.

State of health, in one number

State of health (SoH) is the pack's current usable capacity as a percentage of what it shipped with. A car showing 94% SoH that started life with 300 miles of range is, for practical purposes, a 282-mile car today.

The number comes from the battery management system — the computer that lives with the pack and logs every charge — cross-checked against an actual charging session. We never quote a health figure from a dashboard guess.

What normal looks like

Packs lose a few percent in their first year or two, then settle into a long, slow taper of roughly one percent a year. A five-year-old EV in the low 90s is aging exactly on schedule. Mileage matters less than people assume — climate history and fast-charging habits leave a bigger fingerprint.

Red flags are different: capacity well below the curve for the car's age, cell groups drifting out of balance, or charging behavior that stutters. Those are the cars that fail our inspection and quietly go back to auction.

Using the report as a buyer

Ask for the SoH figure, ask how it was measured, and ask whether the pack is still inside its federal warranty — packs are covered a minimum of 8 years or 100,000 miles, and the clock starts at the original sale, not yours.

If a seller can't produce a health report, that's not automatically a bad car. But it is an unpriced risk — and the price should say so.