What is battery state of health?

State of health compares what the battery holds today with what it held when new. At 94%, a 70 kWh battery holds about 66 kWh.

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eMobility and EV basics · Stop 08How does a battery age?State of health, calendar and cycle ageing, the effect of fast charging and heat, and the minimum durability that EU law sets for new cars.

State of health compares what the battery holds today with what it held when new. At 94%, the 70 kWh battery holds about 66 kWh. The range falls in proportion; the car drives as before.

From “State of health”, stop 08

Terms

  1. State of healthHow much energy the battery can hold today compared with when it was new, in percent.
  1. How fast do electric car batteries degrade?About 2.3% a year on average in telematics data from over 22,700 vehicles. Frequent fast charging above 100 kW went with up to 3.0%, mostly AC charging with about 1.5%.
  2. What is the difference between a hybrid and a plug-in hybrid?A hybrid takes all its energy from fuel; its small battery is filled by the engine and by braking. A plug-in hybrid also charges from the grid, so everyday distances can run on electricity.
  3. What is the difference between LFP and NMC batteries?NMC stores more energy per kilogram. LFP contains no cobalt and costs less: in 2025, LFP packs were on average more than 40% cheaper per kWh.
  4. What is the difference between kW and kWh?kWh is an amount of energy, for example what the battery holds. kW is a rate, how fast energy flows; time equals energy divided by power.