How 90% of EV models are tested for battery condition & state of health
By Niccolò Ferrari, Voltest. Last updated November 2, 2026.
An EV battery health check is a short diagnostic test that reads a used electric car's high-voltage battery and reports its state of health, cell balance and estimated range for that specific VIN. For a dealer, it answers the question nearly every EV buyer asks: how good is this battery?
The test only helps if it works on the car in front of you. Voltest's battery health check works on over 90% of EVs and plug-in hybrids (PHEVs) on the US market, including all major Tesla models[1]. This guide shows which models are covered, what our test data shows by model, which recalls to check, and how to run a test.
Key Takeaways
- Voltest tests over 90% of EVs and PHEVs on the US market, including the Tesla Model 3, Model Y, Model S and Model X.
- Most cars connect through a pocket-size Bluetooth OBD2 device. Teslas use the Voltest Professional Kit adapter.
- A test takes about 2 minutes. You don't need to drive the car or fully charge it.
- Each report is tied to the VIN and shows state of health, cell balance, estimated range and charging history.
- Battery risk in our test data varies by model, even within the same brand, so test every car instead of pricing from a model's reputation.
- A battery health check is not a recall check. Run the VIN at NHTSA.gov/recalls too.
What Does an EV Battery Health Check Measure?
A Voltest battery health check reads data directly from the car's battery management system through the OBD2 port. The report covers four things:
- State of health (SOH): how much usable capacity the battery has left compared with when it was new.
- Cell balance: how evenly charged the individual cells are. A wide voltage spread between cells is the clearest early warning sign of a failing pack.
- Estimated range: the real-world range the car can drive today, shown next to its original rated range.
- Charging history: the car's charge cycle history, including how often it was fast charged.
The report also records battery temperature at the time of the test. It's emailed as a PDF and saved in your Voltest dashboard. For a field-by-field walkthrough, see how to read a battery life report for EVs and plug-in hybrids.
Why not just read the dashboard? The range estimate on the dash changes with temperature, driving style and recent charging, so it isn't a measure of battery health. The car's own health reading can also differ from a validated test, as we explain in why OEM battery health differs from our SoH report.
Which EVs and PHEVs Can Get a Voltest Battery Health Check?
Coverage only matters for the cars you actually stock. The table below shows the supported models US dealers see most often[2].
| Brand | Fully electric models | Plug-in hybrid models |
|---|---|---|
| Tesla | Model 3, Model Y, Model S, Model X | Not applicable |
| Chevrolet, GMC, Cadillac | Bolt, Equinox EV, Blazer EV, Silverado EV, Hummer EV, Sierra EV, Lyriq, Optiq, Escalade IQ | Not applicable |
| Ford | Mustang Mach-E, F-150 Lightning, E-Transit | Not listed for US models yet |
| Hyundai, Genesis | Ioniq 5, Ioniq 6, Ioniq 9, Kona Electric, GV60, Electrified GV70, Electrified G80 | Santa Fe PHEV, Tucson Plug-in |
| Kia | EV6, EV9, Niro EV (listed as e-Niro) | Sorento Plug-in, Sportage Plug-in |
| Volkswagen, Audi, Porsche | ID.4, ID.Buzz, e-tron, Q4 e-tron, Q6 e-tron, Q8 e-tron, e-tron GT, Taycan | Audi Q5 Plug-in, Cayenne E-Hybrid, Panamera E-Hybrid |
| BMW, Mini | i4, i5, i7, iX, Mini Electric | 330e, 5 Series Plug-in, X5 Plug-in, XM, Countryman Plug-in |
| Mercedes-Benz | EQB, eSprinter | Not listed for US models yet |
| Toyota, Lexus | bZ4X, RZ 450e | RAV4 Plug-in, Prius Prime, NX 450h+ |
| Honda, Acura, Nissan | Prologue, ZDX, Leaf, Ariya | Not applicable |
| Jeep, Land Rover, Jaguar | I-Pace | Grand Cherokee 4xe, Range Rover Plug-in |
| Volvo, Polestar | XC40, C40, EX30, EX40, EC40, Polestar 2 | XC60, XC90, S60 and V60 Plug-in |
| Subaru, Mazda, Fiat | Solterra, MX-30, 500e | Not applicable |
This is a sample, not the full list. Check any make, model and year on our supported EVs and PHEVs page. About 40 more models are in development now.
Can You Test a Tesla Battery With an EV Battery Tester?
Yes. Voltest supports the Tesla Model 3, Model Y, Model S and Model X, including Standard Range, Long Range, Performance and Plaid versions. Teslas connect through the Voltest EV Battery Test Professional Kit, which includes the adapter these cars need, instead of the standard OBD2 device.
From there the test works the same way: about 2 minutes, no test drive, and a VIN-specific report. In our data, Tesla Model 3 and Model Y batteries showed failure signals at close to the average rate for all models, across 4,674 vehicles[3]. Teslas lead failure counts only because they make up such a large share of the cars we test.
Battery chemistry matters on Teslas too, since some Model 3s use LFP cells and others use NCA cells. Our LFP vs NCA Tesla battery comparison explains how to tell them apart.
Can You Check a Plug-in Hybrid Battery?
Yes. A PHEV battery health check works the same way as an EV check. PHEVs are easy to skip because they also have a gas engine, but the battery still sets the car's electric range, and buyers still ask about it.
Voltest supports plug-in hybrids including the Toyota RAV4 Plug-in and Prius Prime, Jeep Grand Cherokee 4xe, BMW X5 Plug-in, Volvo XC60 and XC90 Plug-in, Porsche Cayenne E-Hybrid and Lexus NX 450h+.
Because the gas engine takes over when the battery runs low, a weak PHEV pack is easy to miss on a short test drive. Focus on state of health and estimated electric range.
Why Does Test Coverage Matter for a Dealership?
Most used lots carry a mix of brands. In one week you might take in a Model 3, a Bolt, an Ioniq 5, a Mach-E and a Grand Cherokee 4xe. Coverage decides whether every one of them gets tested.
You don't choose what comes in. Trade-ins and auction buys are unpredictable, and a battery problem can hide in a car that looks safe. Our customer in Charlotte, NC tests every car on arrival. When it bought a 2020 Tesla Model Y Performance with 46,000 miles at auction, the test found a major cell imbalance before any reconditioning. The dealer was still inside the return window and got a full refund[4]. It estimated that handling the same problem later, even under warranty, would have cost $3,000 to $4,000 in floor plan, admin and lost turn time.
One process is easier to run than two. When every car gets the same test at intake, testing becomes a habit. When some cars can't be tested, staff start skipping the step on the ones that can.
Your listings stay consistent. Our customer in Bountiful, UT shows battery health right on its search results page, so shoppers see the score before they click. That only works if nearly every EV and PHEV on the lot has a report. Voltest's website widgets put the report on each listing.
What Does Voltest Test Data Show by Model?
We've run over 15,000 battery tests on used EVs[3]. The results below show how often we found a battery failure signal at the time of testing. A failure signal means the cells were badly out of balance or failed a cell-balance check.