EV Battery Health and Warranties: What to Expect in the UK

How EV batteries actually degrade, what UK manufacturer warranties cover in 2026, what State of Health really means, and the daily habits that genuinely extend battery life.

Key takeaways

• Most modern EV packs retain 85 to 90 percent capacity at 10 years with normal use
• UK manufacturer warranties typically cover 8 years or 100,000 miles to 66 to 75 percent retention
• Daily 80 percent charging (or 100 percent on LFP) is the single biggest lever for longevity
• Independent State of Health checks (Aviloo, AA, RAC, dealer tools) are essential before buying used

EV Battery Health & Warranty UK 2026 | What to Expect | TrustWatt on TrustWatt