Don't buy a used EV without reading its battery.
State of Health (SOH) tells you how much of the original battery capacity is left — and therefore what the used EV is actually worth. Dealers won't teach you this. We will, in plain English, with real numbers.
On a used EV, you're mostly buying a battery with a car wrapped around it. A degraded battery silently erases thousands in value.
A used EV can look perfect and drive fine around town while holding 15% less charge than new. Only the SOH number reveals it.
Out-of-warranty battery replacement runs roughly $5,000–$9,000 (Leaf) to $12,000–$20,000 (Tesla Model 3/Y). Know before you pay.
Everything a used-EV buyer needs to read, verify, and price a battery — built for action, not theory.
Enter the asking price and the battery's State of Health. Get an instant read: healthy deal, negotiate, or walk away — with the dollar math shown.
Open the Free Deal CheckerFree, in-depth guides on used-EV battery health. The Toolkit goes further — but this gets you moving.
State of Health explained in plain English — the one number that prices a used EV.
Real degradation curves — Model 3, Bolt, Leaf, ID.4, Mach-E — and why the Leaf ages faster.
Leaf $5–9k to Tesla $12–20k — what a new battery really costs, and when it makes sense.
How to read one line by line — what good and bad actually look like.
When a degraded battery is a bargain — and when it's a $15,000 trap.
The complete guide: SOH, 5 pre-purchase checks, and pricing the car off the battery.
The 20-minute inspection routine: dashboard, reports, test drive, OBD2.
Short answers. The guides above go deep.
SOH — State of Health — is the battery's remaining capacity as a percentage of its original capacity. A 90% SOH battery holds 90% of the range it had when new. It's the single most important number on a used EV.
Typically 1–2% of capacity per year under normal use. Older Nissan Leafs degrade faster because they lack active liquid cooling; Teslas and Chevy Bolts, with thermal management, hold up better.
Not by itself. Dashboard range is an estimate influenced by recent driving and temperature. Always cross-check with a battery report (Recurrent), an OBD2 reading, or a full-charge capacity test.
Yes. The US federal mandate requires automakers to warranty EV batteries for at least 8 years or 100,000 miles, and that coverage transfers to subsequent owners — including used buyers. Check the in-service date: the clock starts at first sale, not when you buy it used.
Sometimes — if the SOH is strong and the price reflects the remaining battery life. Our rule: price the battery first, then decide. A cheap out-of-warranty EV with 85%+ SOH can be a genuine bargain; one at 72% SOH is a future $10k+ bill.
Both have a place. An OBD2 dongle with an app like LeafSpy reads the battery management system directly — the most honest data, but model-dependent. Recurrent reports are easier and standardized across listings, but only as good as their data feed. Use OBD2 when you can physically access the car; Recurrent when shopping online.
Usually good — a documented replacement resets the battery's age clock. Verify the paperwork: who replaced it, with what (new vs. refurbished pack), and whether the replacement carries its own warranty.