When an EV battery dispute ends up in front of the Financial Ombudsman Service, the outcome doesn't hinge on who argues better. It hinges on one question: can anyone prove what state the battery was in on the day the car was sold?
In 2026, MotorCheck — Aviloo's UK distributor — published research analysing every decision the Financial Ombudsman Service has ever made public: 375,328 of them. Within that, they identified 271 verified EV battery complaints, and 49 cases where the Ombudsman explicitly weighed battery evidence in their reasoning. The results were not close.
In all 29 cases where the seller could produce independent, documented evidence of battery condition at the point of sale, the complaint was dismissed — over £580,000 in claims defended. In all 20 cases without that evidence, the consumer won — over £460,000 paid out. The average upheld case was around £29,000.
Why the Split Is So Binary
Under the Consumer Rights Act 2015, if a fault appears within six months of sale, the law presumes it was present at the point of sale — unless the seller can show otherwise. For most components that's a manageable burden. For an EV traction battery, it's brutal: degradation is invisible, the dashboard reading is an estimate produced by the car itself, and by the time a dispute is heard, months have passed and the battery's condition has changed.
These complaints reach the Financial Ombudsman rather than a courtroom because most used EVs are bought on finance — PCP or hire purchase — which makes the finance company jointly responsible for the vehicle's condition. When a battery complaint lands, the finance company turns to the dealer and asks one thing: what evidence do you have from the day of sale?
The Ombudsman's published reasoning in lost cases follows the same pattern, repeatedly citing that "no evidence has been provided" of the battery's condition when the car changed hands. No documentation means no defence.
This Is the Front of the Wave, Not the Peak
EV complaints to the Financial Ombudsman have grown from a single case in 2013 to 96 in 2025, with the last two years up 71% and 93% respectively — and roughly 80% of EV complaints are being upheld in the consumer's favour. Today's disputes come from cars sold three or four years ago, when the UK's EV fleet was a fraction of its current size.
- Around 80,000 EVs have exited manufacturer warranty so far — and they generated today's complaint volume
- Over half a million EVs exit manufacturer warranty between 2026 and 2030
- MotorCheck projects industry-wide complaint exposure could exceed £10 million annually by 2029
Every one of those post-warranty cars will eventually be sold used. Each sale without documented battery condition is an open-ended liability for whoever sold it.
What This Means If You Sell EVs
For a dealer, the maths barely needs explaining. An independent battery certificate at the point of sale — retained against the deal file — is the difference between the 29 dealers who defended £580,000 and the 20 who paid £460,000. One prevented complaint pays for years of testing.
PAD provides Aviloo certified battery tests to dealers across South Wales as a mobile service: we come to your forecourt, the test takes minutes per car, and the certificate is VIN-tied, timestamped, and issued on site. It's the same TÜV-certified standard used by BCA and the major auction groups. See our dealer service page or WhatsApp Alex directly to set up a trade arrangement.
What This Means If You're Buying or Selling Privately
The same logic protects private sellers and buyers. If you're selling an EV, a certificate dated at the point of sale is your proof that the battery was healthy when the car left your hands — the exact evidence the Ombudsman looks for, and the strongest answer to a buyer who comes back months later. If you're buying, insisting on an independent test before you hand over money means you're not relying on a dashboard estimate, and you have a documented baseline if anything goes wrong.
The Evidence Gap figures come from MotorCheck's own research on publicly available Financial Ombudsman decisions — MotorCheck distributes Aviloo in the UK, so read the full paper and judge it on the underlying data, which anyone can verify against the FOS decisions database. And nothing here is legal advice: if you're in an active dispute, speak to a solicitor or Citizens Advice.
The Bottom Line
Across every published Ombudsman decision where EV battery evidence was weighed, documented sellers went 29 for 29 and undocumented sellers went 0 for 20. The certificate that decides those cases costs £95 and takes minutes to issue. Whichever side of a used EV sale you're on, the maths points the same way.