Buy the individual car, not the battery myth

The most expensive component in a used electric car is also the one buyers cannot judge by looking under the bonnet. That makes caution sensible, but it does not mean older EV batteries are generally failing. DEKRA reported in December 2024 that the great majority of more than 25,000 batteries assessed with its independent State of Health procedure remained in good condition, including at higher mileages.

That is useful measured evidence across a large test population, not a guarantee for the car in front of you. DEKRA also highlights high-mileage electric taxi examples retaining roughly 95% to 97% State of Health. Those fleet cases are encouraging, but their maintenance, climate and operating patterns make them case studies rather than a forecast for every privately owned EV.

A 2025 Which? survey, published in April 2026, adds a different kind of evidence. Among 4,444 owners who had bought their EV new, the self-reported average remaining range was 94% for cars first registered in 2018–19. That is a large owner survey, not an instrumented capacity test: it supports the broad durability picture while still leaving room for individual outliers and imperfect memories.

The right response is therefore neither blind confidence nor automatic rejection. Price and select the exact vehicle using an independent battery result, its remaining warranty, service and accident history, and a test drive that includes both AC and rapid charging when practical.

Understand what a State of Health number means

State of Health, usually shown as SoH, estimates how much battery capability remains relative to a defined new-battery reference. The difficulty is that test providers and manufacturers can calculate it differently. A diagnostic read-out may use the battery-management system's estimate, while a longer test may measure energy delivered across a wide charge window. Ask which method was used, the test date, the vehicle software version and whether the result refers to usable energy capacity.

Do not convert a 90% SoH result directly into 90% of the brochure's WLTP range. Real range also depends on speed, temperature, wind, tyres, wheels, heating and the model's original efficiency. The useful comparison is with an independent real-world test of the same battery and wheel specification, adjusted for the tested car's measured health.

A seller-provided dashboard screenshot is weak evidence because the displayed range is influenced by recent driving and climate settings. A manufacturer diagnostic report is better, and an independent certificate is stronger when the test method and tolerances are stated. If a dealer will not allow a battery check on a high-value used EV, treat that refusal as information about the transaction rather than proof that the battery is defective.

  • Match the VIN, odometer reading and test date to the car being sold.
  • Ask whether the figure is a quick diagnostic estimate or a measured discharge test.
  • Compare the result with age and mileage; investigate an outlier instead of relying on one universal pass mark.
  • Keep the certificate with the purchase documents for warranty and future resale discussions.

Read the battery warranty before discussing price

Many European-market EVs were sold with an eight-year battery warranty and a capacity threshold, often around 70%, but the distance limit, transfer rules, exclusions and remedy vary. Some warranties cover a manufacturing failure without promising a particular capacity. Others require the battery to fall below a stated threshold before repair is considered. Obtain the terms for the exact model year and country of first registration, then confirm that the warranty follows the vehicle into Portugal or another destination market.

Check the first-registration date, remaining kilometres and whether scheduled inspections or software campaigns were completed. Ask the manufacturer or authorised repairer to confirm outstanding recalls against the VIN. A warranty claim may lead to repair of a module or restoration to the warranted threshold, not necessarily a brand-new complete pack.

Owner anecdotes are useful for discovering questions: repeated reports of slow charging, coolant faults or unavailable replacement parts justify closer inspection. They do not establish the failure rate of a model because forums rarely show the total number of cars without problems. Use anecdotes to build the checklist; use records, diagnostics and a professional inspection to decide whether to buy.

Test the charging system, not only the range

A healthy battery does not make a complete healthy EV. Confirm that the car charges from a normal AC point at its advertised rate and that the inlet locks and releases correctly. If regular European motorway travel matters, arrange a DC session with the battery warm enough to accept rapid charging. One peak-power number is not a full charging-curve test, but repeated interruptions, warnings or severely restricted power deserve diagnosis.

Check that the portable cable, Type 2 cable and any model-specific adapters promised in the advert are physically present. Inspect the charge-port pins and covers, verify both keys and app transfer, and test preconditioning, navigation and remote climate functions. Older connected services may require a new subscription, a modem upgrade or may no longer support every feature.

Then inspect the ordinary car. EV weight and immediate torque can expose worn tyres, damaged wheels, alignment problems and suspension noise. Look underneath for impact damage to battery shields and lifting points, check corrosion and accident repairs, and test the 12-volt system. An independent used-car inspection remains valuable even when the high-voltage report is excellent.

  • Start the test drive at a recorded charge percentage and note distance, consumption, weather and the ending percentage.
  • Use every charging port and cable supplied with the car.
  • Check tyre brand, size, tread depth and even wear; replacements can materially change the first-year cost.
  • Get an insurance quote and confirm local repair support before paying a deposit.

What Europe's battery passport will—and will not—solve

From 18 February 2027, the EU battery passport becomes mandatory for newly placed-on-the-market EV batteries covered by the Batteries Regulation. The European Commission says the QR-linked record can include identification, performance, durability, repair, reuse and recycling information. Updated Commission guidance published on 21 August 2026 maps 71 possible data points and explains which are mandatory, optional or conditional for each battery category.

This should improve traceability over time, but it will not instantly give every older used EV a comparable lifetime health record. Implementation details and access rights still matter, and a passport is not a substitute for inspecting the rest of the vehicle. Buyers in 2026 should continue to request a current independent battery result and the original warranty documents rather than waiting for future regulation to remove all uncertainty.

The practical conclusion is reassuring but disciplined: measured European evidence suggests widespread rapid degradation is not the normal outcome, while individual variation remains important enough to test. A used EV is ready to buy when its battery evidence, real-world range, charging behaviour, warranty and purchase price all agree—not when one optimistic dashboard number does all the selling.