2025 Battery Performance Index

We’ve published the first edition of our Generational 2025 Battery Performance Index. 

This is the UK’s largest analysis of EV battery condition conducted to date, based on 8,000+ battery health assessments conducted in 2025 across BEVs and PHEVs, passenger cars and LCVs, spanning 0–12 years and 0–160,000+ miles. 

Example findings from the 2025 data:

• Average battery health: 95.15% across all vehicles tested. 
• Even 8–9-year-old vehicles show ~85% median capacity, comfortably above common OEM warranty thresholds (typically 70% SoH). 
• Mileage alone isn’t a reliable predictor: vehicles with 100,000+ miles often return 88–95% battery health.
  
  

The report explains why battery condition transparency is becoming essential infrastructure, and aims to support decision making across the industry, across policy-making, valuation, underwriting, warranty design, fleet management, and remarketing. 

Download the full white paper here.