Note: costs mentioned below are given in US dollars as a general point of reference — actual prices vary by country, currency, and local market.
Battery health is measured as State of Health (SoH) — the percentage of original capacity remaining — not the daily charge level. Fleet data from sources like Recurrent and the US Department of Energy show most EV batteries retain roughly 85-92% of capacity after 8 years/100,000 miles, well within the federal minimum warranty of 8 years/100,000 miles (US) on the battery pack. Hybrid battery health is checked differently, via individual cell-voltage balance rather than a single SoH percentage.
At a glance: checking battery health
| Method | Cost | What it shows |
|---|---|---|
| OEM app (FordPass, myChevrolet, etc.) | Free | Estimated SoH % on supported models |
| Third-party app (Recurrent, Aviloo) | Free-$50 | SoH %, degradation trend, comparison to fleet average |
| OBD-II scan tool + hybrid software | $40-300 | Individual cell voltages (hybrids), pack diagnostics |
| DIY range test | Free (time only) | Rough real-world range vs EPA-rated range |
State of Health vs state of charge
State of Charge (SoC) is just how full the battery is right now — the number on your dash. State of Health (SoH) is what actually degrades over time: it's the battery's current maximum capacity compared to when it was new. A car showing 100% SoC with an SoH of 90% will simply go about 90% as far as it did when new.
Built-in tools by brand
- Many EVs surface an estimated SoH or "battery capacity" figure directly in the infotainment menu or companion app (Tesla app, FordPass, myChevrolet, MyHyundai, among others).
- Some brands don't expose SoH directly — in those cases a dealer service scan tool can pull it during a service visit.
Third-party apps and scan tools
Independent tools like Recurrent (which aggregates real-world fleet data) or Aviloo plug into the car's telematics or OBD port to estimate SoH and show how a specific car compares to the fleet average for its model and age — useful when buying a used EV whose SoH the seller can't produce.
A DIY range test, step by step
- Charge to 100% (or your normal daily limit, noting what it is).
- Reset the trip computer and note the estimated range shown at full charge.
- Drive normally until the battery is nearly empty, tracking actual miles driven.
- Compare miles driven against the original estimated range and against the EPA-rated range for your model.
- Repeat over a few charge cycles in similar weather for a reliable average — a single cold-weather test will understate range and isn't a fair degradation measure.
Hybrid batteries: a different check
Hybrid packs (not EV packs) are usually smaller and checked via individual cell-voltage balance rather than a single SoH percentage — a hybrid-capable scan tool reads each cell's voltage under load; a wide spread between cells is the earliest sign of a failing pack, often well before a warning light appears.
Frequent DC fast-charging, consistently charging to 100% and parking in extreme heat all accelerate degradation. Most manufacturers recommend a daily charge limit around 80-90% for longevity, saving 100% charges for trips.
Frequently asked questions
What's a normal SoH percentage for a used EV?
Does the EV battery warranty cover degradation, not just failure?
Can I check battery health before buying a used EV?
Do hybrid batteries need the same health check as EVs?
How much does battery degradation actually affect range?
Sources & further reading
- US Department of Energy — Alternative Fuels Data Center
- Recurrent — EV Battery Health Reports
- US EPA — Fuel Economy and EV Range Ratings
Figures, prices and policy details were current at the last-updated date above. Automotive pricing, incentives and regulations change frequently — verify time-sensitive details with the linked primary sources. Read our editorial policy and fact-checking standards.
