Used plug-in hybrid: what is the battery worth?
A plug-in hybrid carries a battery several times smaller than an electric car’s, and charges it far more often. It ages differently, its warranty is often shorter, and almost no advert says what state it is in.
The essentials
- The more it has driven on electricity, the more the battery has aged. It is the opposite of what you would expect: a plug-in hybrid charged every day has worked its small battery much harder than one that was not.
- The battery warranty is not an electric car’s. It runs from 6 to 8 years depending on the make, and several manufacturers guarantee no minimum capacity.
- Benchmarks exist. At 100,000 km (about 62,000 miles), ADAC’s experts expect at least 88% of the original capacity.
- The figure is measured, not guessed. Have it established before you buy: out of warranty, a battery costs several thousand euros.
1. A small battery that works hard
A plug-in hybrid’s battery holds around ten kilowatt-hours: 9.8 kWh on a Renault Captur E-Tech plug-in hybrid, according to Renault. An electric car’s commonly holds five times as much. To cover the same distance on electricity, the small one is therefore drained and recharged far more often.
That is what the study published by the German motoring club ADAC on 5 November 2025 measures, on 28,500 plug-in hybrids tested with Aviloo: their batteries are “comparatively small and charged correspondingly more often”, and cars driven largely on electricity have, on average, a noticeably lower state of health than those driven little on electricity.
The study is not alarmist for all that. For most of the cars analysed, it concludes that the battery should last an average vehicle lifetime. But at equal mileage, the spread from one car to the next is wide: usage decides, not the odometer.
2. Ask how it was used
Two plug-in hybrids of the same age and mileage can have two very different batteries. The first, charged every evening, ran mostly on electricity: its engine has little wear, its battery more. The second was almost never plugged in: its battery has done little work, but its petrol engine did everything, hauling the weight of the battery along.
The second profile is common. According to the on-board readings analysed by the European Commission in 2024, plug-in hybrids registered in 2021 emit on the road 3.5 times the CO2 of their official test, because they are “charged and driven in electric mode much less” than assumed. Company cars, numerous on the used market, are the first concerned: in 2022 the ICCT put their electric driving share at 11 to 15%, against 45 to 49% for private cars.
So ask the seller: where was the car charged, and how often? A home charger, charging bills or a history in the manufacturer’s app are worth more than an answer from memory. Neither story rules a car out; they simply are not negotiated the same way.
3. What state of health to expect
State of health (SoH) is the capacity the battery has left, as a percentage of its original capacity. On the basis of their measurements, ADAC’s experts consider that a plug-in hybrid should show at least:
| Mileage | Expected state of health |
|---|---|
| 50,000 km (about 31,000 miles) | at least 92% |
| 100,000 km (about 62,000 miles) | at least 88% |
| 150,000 km (about 93,000 miles) | at least 84% |
| 200,000 km (about 124,000 miles) | at least 80% |
These are recommended thresholds, not measured averages: ADAC publishes its averages only as charts. A car below them has not failed, but its battery has aged faster than can be expected, and that belongs in the price.
On a battery this size, every point counts: at 80% state of health, an electric range of 30 miles when new falls to around 24 miles, before the cold has its say.
4. A shorter warranty, often with no guaranteed capacity
On an electric car, the rule is almost everywhere 8 years or 100,000 miles, with a guaranteed minimum capacity of around 70%. On a plug-in hybrid, nothing of the kind can be assumed. ADAC records warranties of 6 to 8 years and 100,000 to 160,000 km, and notes that a minimum capacity is often absent, or set very low.
Terms vary from one country and one make to the next: ask the manufacturer, with the vehicle identification number, how long the battery warranty runs and what minimum capacity it guarantees, if any.
5. What a battery costs out of warranty
A small battery does not mean a small bill. ADAC puts an out-of-warranty repair between several thousand euros and more than ten thousand, depending on the model.
The only manufacturer price list we found is DS’s in France, reported by Automobile Propre in November 2022: €8,700 for the 12.4 kWh battery of the DS 4, €9,950 for the 14.2 kWh one of the DS 7, €10,950 for the 15.6 kWh one of the DS 9. Per kilowatt-hour, that is about twice the price of an electric car’s battery.
A seven- or eight-year-old plug-in hybrid can therefore near the end of its warranty with a battery whose replacement would be worth a good share of the car’s price. That is the reason to have it measured before buying, not after.
6. Have the battery measured before you buy
Independent measurement exists for plug-in hybrids: Aviloo, whose tests fed ADAC’s study, says it covers more than 96% of electric and plug-in hybrid cars. The result is a state-of-health percentage, to set against the benchmarks above.
No manufacturer-issued state-of-health certificate for a plug-in hybrid could be confirmed at the source.
7. What does not apply to a plug-in hybrid
- The 2027 battery passport. It will cover hybrid batteries, but only those placed on the market from 18 February 2027: a used car bought today will not have one.
- Our checker. It is calibrated on electric cars, whose batteries age differently. We do not apply it to plug-in hybrids: a wrong estimate would be worse than none.
Frequently asked questions
How long does a plug-in hybrid’s battery last?
According to ADAC’s study published in November 2025 on 28,500 plug-in hybrids, the battery of most of them should last an average vehicle lifetime. The spread is wide at equal mileage, however: a car driven largely on electricity has been through far more charging cycles, and its battery has aged more.
What state of health for a plug-in hybrid at 100,000 km?
ADAC’s experts recommend at least 88% of the original capacity at 100,000 km (about 62,000 miles), 92% at 50,000 km, 84% at 150,000 km and 80% at 200,000 km. These are thresholds advised when buying, not measured averages.
How much does it cost to replace a plug-in hybrid’s battery?
According to ADAC, from several thousand euros to more than ten thousand depending on the model. In 2022, DS published prices in France of €8,700 to €10,950 for batteries of 12.4 to 15.6 kWh, about twice as much per kilowatt-hour as an electric car’s battery.
Sources: ADAC, “Plug-in-Hybrid: Akku-Alterung”, 5 November 2025; European Commission, report COM(2024) 122 of 18 March 2024; ICCT, “Real-world usage of plug-in hybrid vehicles in Europe”, June 2022; Renault Group for the Captur’s capacity; Automobile Propre, 11 November 2022, for the DS prices; Aviloo. Checked on 2 October 2026.
Torn between this and an electric car?
For anyone who drives mostly on electricity, ADAC asks the question: would an electric car not make more sense? Its battery is under warranty for longer, and its state of health can be estimated from age and mileage.
Compare electric car batteries