EV Battery Health & Warranties

How EV batteries age, what's actually covered under warranty, and what to watch for over time.

Quick Answer

Federal rules require EV battery packs to be warranted for at least 8 years or 100,000 miles, and several states extend that further. Coverage typically applies if capacity falls below a stated threshold, commonly around 70%. Most packs lose a few percent of capacity early, then degrade slowly.

Part of the AutoNetwork Electric Vehicle Guide.

• EV cost of ownership
• EV charging at home and in public
• How to buy an electric vehicle

Frequently Asked Questions

How long is an EV battery warranty?

The federal minimum is 8 years or 100,000 miles, whichever comes first. Some manufacturers and some states require longer coverage, and terms usually specify a minimum remaining capacity percentage.

What causes EV battery degradation?

Heat, frequent DC fast charging, sitting at very high or very low states of charge, and total energy cycled through the pack. Moderate charging habits and shaded or garaged parking help slow it.

How do I check the health of a used EV battery?

Ask for a manufacturer or third-party state-of-health report, compare the indicated full-charge range against the original EPA rating, and confirm how much of the original battery warranty transfers to you.