Drivers typing 'how to check hybrid battery' into a search engine often see 100% on the dashboard and assume the pack is perfect. The seller usually breathes a sigh of relief too. The problem is that this nice percentage most often refers to the current charge level, not how much battery life is actually left.
If you see '100%' on the dashboard, it is most often SOC (State of Charge), not SOH (State of Health). It looks great in a listing photo, but has only a loose connection to the actual condition of the pack.
In practice, the risk of post-purchase costs is determined by: SOH, pack behaviour under load, voltage delta (Delta V), and temperature and its spread between modules.
Therefore, before buying, don't base your decision on a 'nice indicator' — base it on diagnostic data and a test. A battery doesn't become healthy just because the interface is optimistic.
Wskaźnik vs kondycja
Ładny procent na ekranie nie leczy baterii.
Drivers typing 'how to check hybrid battery' into a search engine often see 100% on the dashboard and assume the pack is perfect. The seller usually breathes a sigh of relief too.
SOC (State of Charge) shows how much energy is currently available. It is a momentary reading that changes with every kilometre and is very often mistaken for something much more important.
SOH (State of Health) describes the battery's degradation relative to factory condition. It is the parameter that really determines the range and value of the car — exactly the part of the story that a simplified screen usually isn't so keen to tell.
In many cars, the manufacturer does not show the driver detailed battery metrics. The user sees a simplified interface and an optimistic presentation of data, because nice percentages sell better than the truth about degradation.
Only a professional SOH battery test and analysis of voltage deltas allow you to understand whether the car is ageing evenly. Without this, you can buy a very nicely charged problem.
In practice, a similar 'masking' mechanism is also encountered in range assessment — if you want to break it down, see our guide: how to check real EV range.
SOC (State of Charge) to ile energii jest teraz w baterii. SOH (State of Health) to ile bateria jest w stanie zmagazynować w porównaniu do fabrycznej pojemności. Dashboard najczęściej pokazuje SOC, nie SOH.
Read more→Over the years 2024–2026, LFP (lithium iron phosphate) technology ceased to be the domain of only Chinese BYD or MG. These batteries have massively entered the base models of European giants (including Volvo, Renault, VW).
They have an extremely 'flat' discharge curve. This means that BMS algorithms handle estimating their degradation much worse than in older NMC cells. This requires using completely different diagnostic and calibration profiles during SOH tests.
Test pod obciążeniem
Pakiet może wyglądać zdrowo tylko do pierwszego większego testu.
Over the years 2024–2026, LFP (lithium iron phosphate) technology ceased to be the domain of only Chinese BYD or MG. These batteries have massively entered the base models of European giants (including Volvo, Renault, VW).
A thorough battery check in an electric car is the foundation of a successful purchase.
In practice, it's the difference between a controlled purchase and a lottery of costs after signing the contract.
Additionally, it's worth comparing SOH with other signals (Delta V, temperatures, charge cycles). This makes it easier to distinguish 'natural wear' from a battery that is starting to have modules diverge.
SOH, Delta V and data under load
It is this set of metrics that really determines the risk of post-purchase costs, not just a 100% reading on the indicator.
If SOH is lower than you expect but the pack behaves stably (small Delta V, even temperatures), you most often have room to negotiate the price.
If there are voltage divergences, charging instability or large temperature differences — the risk increases exponentially and it is often better to walk away from the purchase or require a full diagnostic before signing the contract.
If you want to base your decision on hard measurements, see: on-site pre-purchase audit of a hybrid or EV.
FAQ: SOH, SOC and real battery condition
No. SOC shows the current charge level, not the chemical degradation of the cells. The battery's condition is primarily determined by SOH and how the pack behaves under load.
You need to compare the claims with diagnostic data: SOH, voltage differences, module temperatures, and a charge test. Only this set shows whether the pack is ageing evenly.
Always with a used car, especially if the price is attractive or the service history is incomplete. A pre-purchase test reduces the risk of a costly mistake and gives you a strong negotiating point.
Precyzyjny odczyt SOH, test inwerterów i rozwiązywanie problemów z zasięgiem.
Test baterii, izolacji i lakieru. Nie kupuj hybrydy w ciemno.