What Geotab found
Geotab, a company that collects data from vehicle fleets, tracked 22,700 electric cars across 21 models to measure how fast their batteries wear out in real driving. It found the average battery loses 2.3% of its capacity every year, meaning it can hold that much less charge with each year that passes. Geotab defines a hot climate as a place where more than 35% of days go above 25 degrees Celsius, and a mild climate as fewer than 35% of such days. Cars in hot climates lose an extra 0.4% of capacity every year on top of the 2.3% average.
The extra loss is on top of the average, not instead of it. Geotab did not report a separate figure for mild climates alone, so the 2 bars are the average across the whole sample and the additional hot climate loss, not a mild climate bar and a hot climate bar side by side.
Show the numbers
| Average loss, all climates | 2.3 |
| Extra loss in hot climates | 0.4 |
Geotab says a driver can cut some of the heat exposure that drives the extra wear.
Consider operational adjustments during heat waves such as parking in the shade or indoors to reduce exposure.
Charlotte Argue, Senior Manager, Sustainable Mobility at Geotab. Source 1.
What slows it down
That hot climate penalty is not fixed. A peer reviewed study in the journal eTransportation modeled electric delivery trucks running real routes out of the Port of Savannah, Georgia, a hot and humid location, across 10 simulated years. Modeled with an active thermal management system, equipment that heats or cools the battery pack to keep it inside a safe range, the pack held between 15 and 30 degrees Celsius during the day. Under that control, ambient heat became a bounded, secondary contributor to aging rather than the dominant one. For the nickel manganese cobalt packs modeled, a battery chemistry named for the metals in it, colder seasons aged the battery slightly more than warmer ones, the opposite of what the Geotab number alone would suggest.
A different kind of heat loss
This effect is different from the 0.4% permanent loss above, and it does not last. Recurrent, a separate company with its own vehicle data, studied 29,716 electric cars and found they lose about 5% of driving range at 90 degrees Fahrenheit, 32 degrees Celsius, and about 17% to 18% of range above 100 degrees Fahrenheit, 37 degrees Celsius, mostly from the energy the air conditioning uses to cool the cabin and the battery. That range comes back the next cooler day, because the car is working harder to stay cool, not because the battery is wearing out faster.
How rare failure actually is
A small annual loss is easy to fear more than it deserves. The Environmental Protection Agency states that electric vehicle battery replacements due to failure alone have averaged 2.5% since the earliest models through 2023, falling below 0.5% for vehicles built from 2016 onward. It adds that 97.5% of electric vehicles on the road are still running their original battery, outside major recalls.
All 3 figures come from the Environmental Protection Agency and describe failures outside major recalls. The 2016 onward figure is stated as fewer than 0.5%, shown here as 0.5.
Show the numbers
| Replacements due to failure, earliest models through 2023 | 2.5 |
| Replacements due to failure, 2016 models onward | 0.5 |
| Still on the original battery today | 97.5 |