EV batteries lose capacity gradually, not suddenly. Most warranties are written around that: Tesla’s Model 3 warranty, for example, is 8 years with a 70% minimum capacity, and 100,000 or 120,000 miles depending on variant (verify on tesla.com).
What to do
- Check your age and miles against the warranty with the EV calculator.
- Ask the maker or an independent specialist for a battery health report.
- Get a quote for module repair before accepting a full pack price; see Tesla battery replacement cost.
Never open or work on a high-voltage pack yourself.
What degradation really is
Every lithium-ion battery loses some capacity over time and use. In an EV that shows up as slightly less range than when new, not a sudden failure. The amount depends on how the battery is used and stored, on temperature, on how often it is fast charged and charged to full, and on the battery’s chemistry and cooling. Most owners notice little change for years.
What warranties measure
EV battery warranties normally state years, miles and a minimum capacity. Tesla’s Model 3 terms, as reported by a third party, are 8 years, 100,000 or 120,000 miles depending on variant, and 70% minimum capacity: verify on tesla.com. The capacity clause matters, because it can cover a battery that has degraded beyond the limit even if the car still drives. Use the EV calculator to compare your age and mileage with a warranty.
How to check your battery’s health
- Many cars show a battery health or capacity reading in the service menu or app.
- Dealers and independent EV specialists can run a diagnostic and give a report.
- Track your real-world range under similar conditions over time, remembering that cold weather and speed affect range too.
- Be cautious about third-party apps that estimate health from limited data.
Habits that help
- Avoid leaving the battery at a very high or very low charge for long periods when you can.
- Use fast charging when you need it, but do not rely on it all the time if you do not need to.
- Park in shade or a garage in hot weather.
- Keep the car’s software up to date, since manufacturers adjust battery management through updates.
If the battery really is failing
Get a diagnostic report that identifies the cause. Ask whether a module repair is possible, and compare a new pack, a remanufactured pack and a refurbished pack. Tesla battery replacement cost shows how big the price gap can be. Never open or work on a high-voltage pack yourself.
And the 12V battery
A weak 12V battery can cause strange warnings and a car that will not wake. Rule it out first: the 12V battery in hybrids and EVs.