According to its website, Carla was one of the first used-car marketplaces to test and evaluate battery health before putting cars up for sale, giving it a remarkably diverse data set on degradation. Using that information, Carla looked at the batteries of 9,954 EVs during a four-year period using the global-standard AVILOO diagnostics system, and the online auto retailer discovered that after 10,000 Swedish miles (equivalent to 100,000 kilometers or 62,137 miles), many of the [most popular makes and models](https://carbuzz.com/cars/electric-cars/) had lost between five and eight percent of their original capacity.

The study also discovered that, on average, CATL [LFP batteries](https://carbuzz.com/news/tesla-has-found-a-way-to-use-lfp-batteries-and-qualify-for-full-ev-tax-credit/) retained more than 93 percent health, eclipsing LG Energy Solutions' lithium-ion pouch cells (91.5 percent) and Panasonic batteries (between 88.2 and 89.8 percent). The data set only included vehicles with a sufficient number of tests to reduce any outliers, although Carla didn't specify what that number was.

Amazingly, two of the cheapest, least sophisticated EVs on the market took home top honors in Carla's test. Coming in first was the battery-powered Niro, with 97.25 percent of its stated capacity remaining on the AVILOO test. The mechanically identical [Hyundai Kona Electric](https://carbuzz.com/cars/hyundai/kona-electric/2025/) followed close behind at 97.18 percent battery health. 

Both Korean EVs use a liquid-cooled 64-kilowatt-hour battery (although newer model years also offered a 48.6-kWh standard-range variant), giving them roughly 260 miles of range in EPA testing. If Carla's numbers are accurate, Niro and Kona owners can still expect more than 250 miles on a full battery after 62,000 miles.

What is surprising is that no Tesla models broke into the top five in Carla's testing, odd considering the brand has been working on battery technology for literally decades and currently builds the [best-selling EV in the world](https://carbuzz.com/tesla-model-y-cheaper-june/). The only one to crack into the top 10 in Carla's testing was the eighth-place [Model 3](https://carbuzz.com/cars/tesla/model-3/2026/) with the base 60.5-kilowatt-hour CATL battery found in most of the entry-level models sold in Europe. That variant retained 93.34 percent of its capacity, compared to 92.83 percent for the 78.8-kWh LG Chem battery found in the 12th-ranked Model 3 Long Range.

Hyundai, Kia, And Even Volvo Just Beat Tesla At The Game It Created