Providing battery state of health (SOH) certificates drastically increases buyer engagement, online views and bidding activity for used electric vehicles at auction, according to a six-month trial by automotive data firm Volteras.

The study, which specifically analysed Tesla Model 3 remarketing data, demonstrated that transparency around battery health is the key to building buyer trust and accelerating transaction times in the secondary EV market.

By selecting similar Tesla Model 3 vehicles of comparable age, mileage and CAP ID, Volteras compared the auction performance of cars equipped with an SOH certificate against those without one.

The certified EVs saw significant performance spikes. Teslas with a Volteras certificate received 20% more advert views prior to the online auction. They also gained 34% more unique advert views, 10% more bids and 4% more unique bidders.

Prices remained identical with or without a certificate, but the trial proved that Volteras helped gain increased trust with buyers leading to a faster used EV sale.

Barney Hewlett, Volteras head of product design, said the trial has been highly valuable in identifying how state of health certificates can build trust with buyers and vendors when selling vehicles at auction.

“This makes a big contribution towards helping used EVs gain credibility as they become an integral part of the used car ecosystem,” he added.

By using OEM vehicle data accessed through Volteras connected vehicle APIs, battery SOH can be calculated without requiring hardware installation or physical vehicle connection.

This approach provides continuity with data being collected over time through a connected vehicle relationship with battery health monitored continuously rather than measured once. That connected period may span weeks, months or even years to create a different method to understanding battery performance.

This ‘longitudinal view’ enables more informed decision-making with trends identified earlier, and anomalies becoming visible, while vehicle performance can be benchmarked across comparable populations.

Volteras stressed that the result is not simply a battery health score, it is an evolving picture of battery condition and performance over time, enabling better operational decisions, stronger asset management and more proactive battery lifecycle management.