Battery degradation is the single biggest reason Czech, Slovak and Polish buyers still hesitate over a used electric car. A new analysis from the Czech Transport Research Centre (Centrum dopravního výzkumu, CDV) and the used-car group AURES Holdings put a number on it, and the number is not the one the fear implies.
The team analysed independent diagnostics on 3,171 plug-in vehicles sold across the Czech, Slovak and Polish markets — 2,742 battery-electric cars and 429 plug-in hybrids — tested between July 2024 and March 2026. Every pack was measured with the Aviloo Flash Test rather than read off the car's own display, which matters: a manufacturer's state-of-health readout is not an independent measurement.
What the packs actually had left
State of health is the share of a pack's original usable capacity still available. Medians, by distance driven:
| Mileage | Battery-electric | Plug-in hybrid |
|---|---|---|
| Up to 40,000 km | 96.0% | 97.0% |
| 40,000–100,000 km | 93.0% | — |
| Over 100,000 km | 90.3% | 88.0% |
A typical battery-electric car past 100,000 km had lost under a tenth of its capacity. On a car with 500 km of range when new, that is roughly 50 km gone.
Age did more damage than distance
The finding CDV leads with is the comparison between the two tables it built. Sorted by age instead of mileage:
| Vehicle age | Battery-electric | Plug-in hybrid |
|---|---|---|
| Up to 3 years | 96.1% | 95.0% |
| Over 6 years | 90.0% | 83.2% |
"Age plays a more significant role than pure kilometre count in assessing battery condition," said Robert Závala, the CDV researcher who led the work.
The electric cars make that case weakly — 90.0% by age against 90.3% by mileage is barely a gap. The plug-in hybrids make it strongly: 83.2% for the over-sixes against 88.0% for the high-mileage cars. That fits how the two are driven. A plug-in hybrid accumulates calendar years while its small pack does relatively little work, so what wears it is time rather than cycles.
For a used-car buyer the practical reading is that the odometer is the wrong thing to fixate on. A six-year-old car with 40,000 km is not obviously the safer buy.
How this sits against the wider data
Two months ago Aviloo published its first Battery Report, drawing on more than half a million tests, and put the Tesla Model Y at a median 90.3% at 150,000 km. The identical figure is a coincidence worth naming rather than a confirmation: Aviloo's is one model at 150,000 km, CDV's is a whole regional fleet past 100,000 km.
Both point the same way, and both carry the same caveat. Aviloo's report found the spread between individual cars of one model widens with mileage, and a separate strand of its data shows one used EV in 85 hides a cell imbalance that a state-of-health number will not reveal. A median describes the market. It does not describe the car in front of you.
What it means for European owners
Czechia registered 11,665 electric cars in the first eight months of this year, and its used market is where most of those cars will end up. Regulation is moving the same way: France now shows battery health on used EV listings, and from 29 November the EU's Environmental Vehicle Passport puts state of health in the car itself.
Detailed results appear in Silniční obzor 7–8/2026, pages 34–39, by Závala, Bucsuházy, Kadula and Dedek. CDV presents them on 1 October at the Czech Ministry of Transport's "Clean Transport: From Plans to Action" conference.