An EV battery health report is the written result of a diagnostic test run by a dealer or the car’s manufacturer. It states the battery’s measured state of health — how much usable capacity the pack holds compared with when it was new — and flags faults in individual cells or modules. It is the most formal way to check battery degradation: the dashboard figure is the car’s own estimate; a health report is a measured result you can keep.
Key Takeaways
- A battery health report is a dealer diagnostic document: measured state of health, capacity, cell flags and fault codes.
- Ask for the test by name, and ask the fee first — prices vary by maker and region.
- Get one before buying a used EV and before the battery warranty ends.
- A report is a snapshot, not a forecast; the trend across dated reports is what matters.
What the Report Typically Includes
The layout differs by brand, but most reports cover the same ground:
| Item on the report | What it tells you |
|---|---|
| State of health (SoH) | Capacity as a percentage of the original usable capacity — the headline degradation figure |
| Estimated usable capacity | The energy the pack can hold now, usually in kWh, set against its original rating |
| Cell or module flags | Whether any cell group sits far from the rest, which points to a fault rather than even wear |
| Stored fault codes | Battery or charging faults the management system has logged, even ones that never lit a warning |
| Charge history counters | On some models, totals such as DC fast-charging sessions, which help explain the wear pattern |
If a line is missing, ask about it — contents vary by maker and test equipment, and a report that shows only one percentage tells you less than one that shows the detail behind it.
How to Get a Report
- Book the test by name. Ask the dealer or authorised service centre for a battery health test with a printed or digital report — a routine service does not always include one.
- Ask the fee first. Costs vary by maker and region, so get the figure before you book, not at the desk afterwards.
- Use it before you buy. When buying used, ask the seller for a recent report, or pay for a test before you commit. It is the strongest of the methods in our guide to how to check EV battery health.
- Time one before the warranty ends. A dated report made while the battery warranty still runs documents any excessive loss while cover may still apply. Our article on whether an EV battery can be replaced or repaired runs through the options if a fault is found.
Keep every report. One result is a snapshot; a file of dated results is a history — the clearest evidence you can hand a buyer, dealer or warranty desk later.
What a Report Cannot Tell You
A report measures the past, not the future. It shows the loss the pack has today, and it cannot turn that into a date when the battery will reach any given level. Readings can also shift slightly with temperature and method, so compare like with like before concluding anything changed. FuelEconomy.gov cites DOE estimates of 12 to 15 years of battery life in moderate climates and 8 to 12 in severe ones — see our explainer on whether EV batteries degrade over time. One healthy report plus slow change over years is the normal pattern.
Between Reports: Track the Trend at Home
You do not need test equipment for the rough trend. A charger that displays the energy it delivers, such as the EVDANCE EV-ACS4005T 40A NACS portable charger (9.6 kW, adjustable at 16/24/32/40 A), lets you note the kWh added between the same two charge levels every few months. A wall unit such as the EVDANCE EV-ACT5006T 48A Level 2 wall charger makes that routine automatic. If your notes and the car’s estimate start drifting sharply apart, that is the moment to book the formal test.
Frequently Asked Questions
How is a health report different from the state of health shown in my car?
Some cars display a state-of-health figure, but the car calculates it from its own data. A report comes from a dealer diagnostic test, adds cell-level and fault detail the dashboard never shows, and gives you a document to keep.
Should I get a battery health report before buying a used EV?
Yes, if you can. It is the strongest single check on the most expensive part of the car. Pair it with questions about charging history, and be wary of a seller who will not allow a test.
How often should I have a health report done?
No fixed interval exists. Sensible moments are before buying a used car, before the battery warranty expires, or when full-charge range drops and stays down in mild weather.
Related Reading
- How to Check EV Battery Health
- Does an EV Battery Degrade Over Time?
- Can an EV Battery Be Replaced or Repaired?
- Does Level 2 Charging Shorten Battery Life?
