New Swedish data busts EV battery degradation myths

A large-scale Swedish study of 1,300 EVs reveals that most retain over 90% battery capacity, challenging degradation myths and boosting used EV confidence.

A large-scale study from Swedish marketplace Kvdbil has dealt a serious blow to one of the biggest myths surrounding electric vehicles — rapid battery degradation. Researchers examined the battery health of more than 1,300 used EVs and plug-in hybrids, including 723 fully electric models. The results were strikingly positive: eight out of ten cars retained more than 90% of their original capacity.

Martin Reinholdsson, Kvdbil’s test manager, explained that such endurance is the result of advanced cooling systems and well-engineered battery designs. He noted that while all batteries naturally degrade over time, the pace is far slower than critics have long claimed.

The top performers in the study were the Kia EV6, Kia e-Niro, and Tesla Model Y, followed by the Opel Mokka-e, Mazda MX-30, Audi Q4 e-tron, Fiat 500e, Volvo XC40 Recharge, Citroën e-C4, and Volkswagen ID.4. When ranked by brand, Tesla placed fourth overall, just behind Kia, Audi, and Opel.

These findings align closely with broader research. Data from Geotab and U.S. analytics firm Recurrent show that most EV batteries lose only about 1.8–2% of capacity per year. German institute Fraunhofer has similarly reported that modern lithium-ion batteries can retain over 80% of their energy after ten years of use.

Charging habits also play a crucial role in preserving battery health. Experts recommend limiting daily charging to around 80% and avoiding frequent DC fast-charging — practices that telematics data consistently support.

Modern liquid-cooled lithium-ion packs have proven remarkably durable. Increasingly, evidence suggests that EV batteries may outlast the vehicles themselves, giving the used electric car market a much-needed boost of confidence.