As cars age, their performance tends to gradually deteriorate. In the case of electric cars, that could include battery degradation, where the effective electrical storage capacity is reduced due to wear and tear on the cells. Battery degradation was a pretty significant problem in early EVs, with some cars like the first-generation Nissan Leaf often losing a third or more of their range after only five or 10 years.
Keen to put such fears to rest, Tesla has released its own data on the matter, finding that in 200,000 miles, a Model S sedan will have lost only about 12 percent of its range, translating to about 220 miles on the decade-old P85 trim level. But despite that impressive result for a well-aged battery, Tesla doesn’t actually take the cake. According to Swedish EV and plug-in hybrid marketplace Carla, the electric car with the most durable battery is also one of the cheapest: the Kia Niro EV.
Establishing The Ground Rules
BYD 1,500-kilowatt Flash Charge stationBYD Fans
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 had lost between five and eight percent of their original capacity.
The study also discovered that, on average, CATL LFP batteries 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.
Cheap And Cheerful Wins The Race
2026 Kia Niro EVKia
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 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.
Hyundai
Another Kia product, the admirable EV6, came in third with 95.95 percent, followed by the hometown-boy Volvo XC40 Recharge at 94.7 percent. Rounding out the top five is another Swede, the Polestar 2, which had a tested battery health of 94.35 percent when equipped with the CATL battery found in 2023–2025 models. The XC40 and Polestar nearly tying shouldn’t be a surprise considering they’re platform-mates equipped with the same energy storage unit and electric motors.
Overhead view of a 2017 Tesla Model 3Tesla
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. The only one to crack into the top 10 in Carla’s testing was the eighth-place Model 3 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.
Extrapolated to real-world numbers, the base Model 3 should still offer 253 miles per charge after 62,000 miles, while the Long Range model sees 332 miles between charging stops.
Sweden-Tested, Perhaps Not World-Approved
2024 Volvo XC40 Recharge Gray Front Angled View DrivingVolvo
While the numbers are promising – every top-20 ranked EV in Carla’s evaluation had at least 91 percent of its battery capacity left – they may not quite tell the whole story. A relatively small sample size may have skewed the outcome somewhat, considering it included fewer than 10,000 EVs compared to the literal millions sold in the US each year. Drawing large-scale conclusions from the test is probably more difficult than the results would suggest.
Another point to consider is the unique market in which those EVs are used. Since the test took place in Sweden, it is reasonable to assume that the cars endured colder weather than they might on average – the country’s average high temperature in the summer ranges between a brisk 65 degrees and a breezy 73 degrees Fahrenheit. Since cold weather is less damaging to battery cell health than hot weather, one could expect more degradation in more temperate or warmer regions of the world. We’d very much like to see a similar dataset from Los Angeles to compare how each battery would fare there.
Scandinavia and Europe in general are also more accommodating of EVs than the US, owing to the region’s more centralized population density. As a result, it’s easier to find regular EV charging on city streets and in shopping centers, whereas American consumers must either install home chargers or use the DC fast chargers that are more common in public. And since DC fast charging is worse on batteries than AC “trickle” charging, we suspect American EVs might score worse in a similar test.
How To Avoid Battery Degradation
2026 Dodge Charger DaytonaDodge
If you own an electric vehicle (or are considering buying one), there are some tips you can use to ensure your big automotive investment pays off. Heat is the most serious driver of battery degradation, although most modern EVs have liquid-cooled cells that can cope with high ambient temperatures, leading to less range deterioration. Ensuring your battery’s coolant is at the proper level and in good condition can help keep it healthy.
The less obvious (and more ironic) source of heat is a charger. Plugging in raises battery temperatures, getting much hotter during DC fast charging than during 120- or 240-volt AC charging. Avoiding a high-power charger can improve battery longevity, but if that is not possible, remember that heat stress compounds with higher charging rates. So while it may be tempting to plug into that 400-kilowatt Ionna station, choosing a slower 50- or 100-kilowatt speed is better for the battery if you have the time. Of course, the healthiest solution is to charge using AC power at home, but that’s not always possible for all EV owners.
Tesla Model 3 Charging at Ionna Charging StationIonna
It is also best to charge, irrespective of method, to only about 80 percent of the battery’s total capacity. The closer your car’s battery state-of-charge (SoC) gets to 100, the more internal voltage (and therefore heat) it generates. The same is true for discharging, with more cell wear happening as the SoC goes below 10 percent. That’s why most auto manufacturers quote a 10-to-80-percent charge time in their literature, as that seems to be a battery’s happy place for longevity and range.
Finally, if your EV is parked for long periods of time, it might be a good idea to connect it to an intelligent power unit (such as a vehicle-to-home inverter) to gradually discharge and recharge the battery. If that’s not possible, it’s better to park an EV with less than 40 percent SoC than one with 80 or 90 percent.
If you take those precautions as often as possible with your EV, you will be much more likely to enjoy the mild level of degradation reported by our Swedish friends at Carla – whether you drive a Tesla or not.
Base Trim Engine
EV
Base Trim Transmission
Automatic
Base Trim Drivetrain
Front-Wheel Drive
Base Trim Horsepower
201.1 HP @6000 RPM
Base Trim Torque
187.8 lb.-ft.
Base Trim Fuel Economy Equivalent (city/highway/combined)
126/101/113 mpge
Base Trim Battery Type
Lithium ion (Li-ion)
Source: Carla
