Battery degradation

The gradual loss of battery capacity, and therefore range, as an EV ages and accumulates charge cycles. Sources describe the loss as slow.

Last reviewed

Every lithium-ion battery loses some capacity as it ages and cycles, and in a car that shows up as slowly shrinking range. The Australian Government says all batteries degrade slowly and describes new EV batteries as expected to last 13 years or more. The US Department of Energy adds that studies have shown an EV battery could still have at least 70% of its initial capacity at the end of its life, if it has not failed or been damaged.

State of health is the usual measure: the Australian Government defines it as the battery's condition and performance compared with when it was new, generally as a percentage, with 100% being the original state. Many EVs show it through onboard diagnostics or apps.

Habits may matter. The Australian Government says frequent use of fast or ultrafast chargers (50 kW or above) may cause marginally faster degradation than lower-powered chargers such as home units, and that regularly charging to 100% may be detrimental depending on the battery type, so it points owners to their manufacturer's advice.

Manufacturers back their batteries with separate warranties; see battery warranty for what to check.

  1. Australian Government, Preparing to buy an electric vehicle
    Australian Government Accessed
  2. Australian Government, Electric vehicle facts
    Australian Government Accessed
  3. Australian Government, Electric vehicle maintenance and servicing
    Australian Government Accessed
  4. US DOE Alternative Fuels Data Center, Batteries for Electric Vehicles
    US Department of Energy Accessed

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