Three UK electric-vehicle organisations have asked the government to make battery health certificates compulsory on every used EV sold by a dealer — a single, standardised document stating what capacity the pack has left. Electrifying, New AutoMotive and BatteryIQ want it treated the way an MOT is treated: not a marketing extra, but a condition of sale.
The argument is that the used market has grown past the point where "trust the seller" is good enough. There are now more than two million EVs on UK roads, and used EV sales passed 110,000 in a single quarter. The second-hand buyer is no longer an enthusiast who understands degradation curves.
What the surveys actually say
The numbers behind the campaign describe hesitancy rather than hostility.
| Finding | Figure | Source |
|---|---|---|
| Would not buy a used EV without a battery health certificate | 57% | Startline Motor Finance |
| Worry about potential battery failure | 77% | Startline Motor Finance |
| Say an independently verified certificate would raise their confidence | 38% | AA and Electrifying, 13,000 drivers |
The gap between those figures is the interesting part. Far more people are worried about battery failure than say a certificate would fix it — which suggests the certificate is a floor, not a cure, and that the industry still has an explaining problem underneath the paperwork problem.
The data does not support the fear
What makes this a confidence gap rather than a quality gap is that used EV batteries are, on the evidence, holding up well. The Generational Battery Performance Index puts average retained battery health across used EVs at around 95%. Buyers are pricing in a risk that the fleet data does not show.
That mismatch is exactly what a standardised certificate is meant to close. A seller with a healthy pack currently has no cheap, credible way to prove it, so every car gets discounted as though it might be the bad one. Several sellers have moved without waiting for legislation: Polestar, Motorpoint, BCA, Cambria and Arnold Clark already offer battery health checks.
Why a Tesla owner should care
Used Model 3s and Model Ys are among the highest-volume used EVs in the UK, so a rule of this kind would apply to a great many Teslas and would reshape how they are priced. Tesla is unusually well placed for it — the pack reports its own state of health, and Tesla's chemistry and thermal management have a long real-world record — so a mandatory certificate would tend to reward cars that hold capacity rather than punish them.
There is also a legal argument running in parallel on the continent. A German court in Celle recently held that normal battery capacity loss is not a defect, which settles what a buyer can demand after the sale. A health certificate settles the other half: what a buyer knows before it.
What happens next
Nothing automatic. This is a call on government, not a regulation, and no departmental response has been reported. The likely path is the one the campaign is already walking — voluntary adoption by the larger dealer groups building enough of a norm that mandating it becomes an administrative step rather than a fight.
For anyone selling a used Tesla in the UK in the meantime, the practical read is straightforward: a documented state-of-health figure is becoming a thing buyers expect, and it is easier to have one than to argue about not having one.