Electric vehicle owners have long worried that frequent use of DC fast chargers could degrade their car’s battery more quickly, with this also affecting the reputation of used electric cars. But a new study by Recurrent Auto suggests there’s nothing to fear when it comes to fast charging impacts on battery health.
The study compared Tesla vehicles that were fast charged over 90% of the time to those fast charged less than 10% of the time. It found virtually no difference in battery degradation rates between the two groups. This suggests fast charging in and of itself does not accelerate battery degradation in a significant way.
While fast charging seems to be safe for batteries, Recurrent still recommends best practices for maximising battery life:
- Precondition the battery in extreme heat or cold. This allows the battery to accept a faster charge rate without overheating. Teslas in particular will precondition the battery automatically when navigating to a Supercharger location.
- Avoid charging at the extreme low or high ends of the state of charge. Resistance is higher at very low and very high charge levels, putting more strain on the battery. Most EVs reduce fast charging speeds above 80% state of charge for this reason.
- Switch to slower Level 2 charging for the last 20% of charging. This is often just as fast as fast charging above 80%, and cheaper too.
The impacts of other factors like battery chemistry, temperature fluctuations, and age are still being researched. But Recurrent’s findings should reassure EV drivers that normal DC fast charging won’t prematurely degrade their batteries.
When and how to charge remains confusing for some new EV owners. The capability for fast charging is not the same as the need for it. An EV can be plugged in any time it’s parked, taking advantage of cheap overnight charging at home. Public fast charging, while convenient for travel, costs up to twice as much per kWh.
The speed of a fast charging station refers to its maximum output, not what any given vehicle can accept. For example, a 50kW Chevrolet Bolt cannot meaningfully charge faster on a 250kW charger. Knowing your vehicle’s maximum charge rate can prevent frustrations.
But even charge time is a moot point for most daily local driving, with home charging overnight. The concept of wait times to “refuel” an EV just doesn’t apply for most trips the way it does for gas cars.
For road trips, planning charging stops ahead of time ensures a smooth journey. Apps and in-car navigation make this easy, identifying chargers along your route and preconditioning the battery. While charging times are improving, travelers should still budget extra time to account for charging stops.
The charging infrastructure for EVs improves every year, making range anxiety a thing of the past. But careful charging habits maximise efficiency and battery longevity. Avoiding extremes of temperature and state of charge, mixing in slower Level 2 charging, and taking advantage of home charging (check out our EV charger reviews) will keep your EV battery happy for the long haul.
Source: Recurrent Auto.