Battery Health, Not Bumper Shine: How to Vet a Used EV Before You Sign

Used electric cars have moved from novelty to normal. In 2026 there are genuine bargains on forecourts, and there are also cars that look lovely and hide a tired battery. The difference is not always obvious from the driver's seat. At Hyde Motors we are not here to hype EVs or bury them. We are here to help you ask the questions that separate a sensible used purchase from an expensive experiment.

Why battery health matters more than mileage

On a petrol car, mileage tells you a lot. On an EV, it tells you less than you think. A high-mileage car that was charged gently and kept within a sensible window can be healthier than a low-mileage car that was rapid-charged constantly and left at 100% for weeks. The number that matters is state of health, usually shortened to SoH. It is a percentage of the battery's original usable capacity. A car at 92% SoH is not the same proposition as one at 82%, even if the odometer says otherwise. Battery warranties often run for eight years or 100,000 miles to around 70% capacity, but the useful life and the warranty life are not the same thing. If the car is seven years old, the warranty clock is nearly run out.

Question one: can I see a recent state-of-health report?

A seller saying the battery is fine is not evidence. Ask for a recent diagnostic report from a main dealer or a recognised battery health specialist. Look for the SoH figure, cell balance, fault codes and any history of battery-related repairs. Some cars can show a manufacturer app report; others need a proper diagnostic session. If the seller cannot provide anything, that is not automatically a walk-away, but it should change your offer. A cheap EV with no battery evidence is a gamble. A slightly dearer one with a clean report is a bargain.

Question two: does the battery warranty transfer to me?

Most manufacturer battery warranties transfer to the next owner, but not all do, and the conditions matter. Ask for the warranty document, the in-service date and the mileage cap. Check whether the car needs annual health checks to keep the warranty valid. If it has missed a service or a recall, the warranty may be compromised. Get the answer in writing. This is not a rude question; it is the same as asking for a cambelt invoice on a petrol car.

Question three: what range should I actually expect in a cold snap?

The official range figure is a laboratory number. In a British winter, with the heater on, lights on and motorway speeds, expect noticeably less. A drop of 20% to 30% is common on many cars, and more in severe cold. A heat pump can help, but it is not magic. Ask the seller to start the car from cold and take it on a test route that includes a fast road. Check the predicted range, the consumption figure and how quickly it falls. Do not rely on the guess-o-meter alone. Use it as one clue among several.

Question four: how has it been charged?

Charging habits are harder to prove than mileage, but they are worth asking about. A car that lived on a home charger and was rarely run below 10% is generally a safer bet than one that was rapid-charged every day and left at 100%. That said, modern battery management systems are clever, and a high rapid-charge count is not an automatic red flag. Look at the overall SoH report, the age of the car and the cooling system. If the seller is vague, ask for the report. Evidence beats a story.

Question five: can I charge at home?

This is the practical question that decides whether an EV works for you. Do you have off-street parking? Can you get a dedicated 7kW home charger fitted? What would it cost, and does your consumer unit have space? A standard three-pin granny cable is better than nothing, but it is slow and best treated as a backup. Check the charging cable that comes with the car, the condition of the charging port and whether the car supports the charging speeds you need. If you rely on public charging, look at the chargers near home and work before you buy. A cheap EV that is awkward to charge is not cheap in hassle.

Question six: what else is different from a petrol car?

EVs are heavy, so tyres wear faster and can be pricey. Regenerative braking means the friction brakes get less use, which can lead to corroded discs if the car has been sitting. Check the brakes properly on the test drive. Ask about software updates, recalls and whether the car has the latest charging software. Check the service history, the MOT history and the tyres. Vehicle excise duty now applies to EVs, so check the rate rather than assuming it is zero. Insurance can also be higher than expected, so get a quote before you commit.

A short, dealer-friendly checklist

Ask these before you sign:

• Can I see a recent SoH report with cell balance and fault codes?
• Does the battery warranty transfer, and what is the expiry date and mileage cap?
• Has the car missed any recalls or battery health checks?
• What range does it show from cold on a mixed test route?
• How was it charged, and can you show any evidence?
• Does it come with both charging cables, and do they work?
• What is the tyre tread and brake condition?
• What is the VED rate and insurance group?

The Hyde view

A used EV can be a brilliant buy. Quiet, cheap to run and surprisingly relaxing once you understand the charging routine. But the battery is the car. If the seller cannot evidence its health, you are buying a mystery with a nice interior. Ask the questions, get the report, test it cold and budget for the first year. That is not anti-EV. It is just straight advice.