Tesla battery health: what degradation is and how to read range loss honestly

What battery degradation is

A lithium-ion battery slowly loses the amount of energy it can store. The share it still has, compared with when it was new, is called state of health (SoH). A car with 90% SoH holds roughly 90% of its original energy, so a full charge takes it roughly 10% less far.

Two things wear a battery. Calendar ageing happens with time, even when the car is parked, and is faster when the battery is warm and full. Cycle ageing comes from charging and driving. Most packs lose more in the first years and then level off.

How much Teslas actually lose

The largest independent dataset is Aviloo's September 2026 report, built on more than 500,000 battery tests of used EVs. The median Model Y was at 94.5% SoH at 50,000 km and 90.3% at 150,000 km, according to ecomento's write-up. Electrek reports the Model 3 at 93.8% and 88.9% at the same distances, and notes that both Teslas sat in the lower third of the 20 models. Individual cars of the same model differed by up to 11 points.

Geotab's fleet data (more than 22,700 EVs, updated April 2026) shows an average loss of 2.3% per year across brands. Tesla's own 2022 Impact Report said Model S and Model X lose about 12% after 200,000 miles (about 320,000 km). Recurrent, which follows around 15,000 cars, found that only 1.5% had had their battery replaced.

• Model Y median: 94.5% at 50,000 km, 90.3% at 150,000 km (Aviloo via ecomento)
• Model 3 median: 93.8% at 50,000 km, 88.9% at 150,000 km (Aviloo via Electrek)
• Average across brands: 2.3% per year (Geotab)

What speeds wear up

Geotab's data points to three habits. Cars in hot climates lose about 0.4 percentage points more per year. Cars that spend a lot of time at a very high or very low charge level age faster than cars kept in the middle. And cars that do more than 40% of their charging at 100 kW or more lose about 3.0% per year instead of 2.3%.

Not every study agrees on fast charging. Recurrent compared about 13,000 Teslas and found no statistically significant difference in range loss between cars that fast-charge most of the time and cars that rarely do. The honest reading: occasional fast charging is fine; a pack that lives on high-power chargers in a hot place is the case to watch.

• Leave the car plugged in and use the daily charge limit Tesla recommends for your pack
• Charge to 100% before a long trip, not as a habit (LFP packs are the exception: Tesla advises charging them to 100%)
• Avoid parking for days at a very high or very low charge in the heat

Why the range on the screen is not a battery test

The range figure is the battery management system's estimate of stored energy multiplied by a rated consumption. The estimate drifts. Recurrent explains that if you always charge between about 20% and 80%, the system has fewer reference points and the displayed range can fall, then recover after a full charge. A single low reading on a cold morning says little.

Tesla used to offer a Battery Health test in the car's service menu. Not a Tesla App reported in August 2025 that update 2025.26 removed it on many cars, without an explanation in the release notes. For a reliable number, use an independent test such as Aviloo (offered in Germany through ADAC), or compare the range at 100% over several months rather than one day.

What the warranty covers

Tesla's battery warranty runs for 8 years with a mileage limit that depends on the model and version, and it promises at least 70% retention within that period. In Turkey, press reports give 160,000 km for the rear-wheel-drive Model Y and 192,000 km for Long Range and Performance versions. Check the warranty booklet for your exact car: the limits changed between model years.

Because typical loss sits far above the 70% line, the warranty mainly protects against a defective pack, not normal ageing.

Frequently asked questions

How much battery capacity does a Tesla lose per year?

Across brands, Geotab measured 2.3% per year on average. Loss is usually faster in the first years and slower after. Aviloo's 2026 data puts the median Model Y at about 94.5% after 50,000 km and 90.3% after 150,000 km.

Does Supercharging damage the battery?

Occasional fast charging is not a problem. Geotab found faster wear when more than 40% of charging happens at 100 kW or more, while Recurrent found no significant difference among Teslas. Heat plus frequent high-power charging is the combination to limit.

Can I still run the battery health test in my Tesla?

On many cars, no. Update 2025.26 removed the Battery Health test from the service menu for a large share of vehicles, according to Not a Tesla App. An independent test, such as Aviloo's, is the alternative.

At what point does the warranty replace the battery?

Tesla's battery warranty covers capacity falling below 70% within 8 years and the model's km limit. Normal ageing rarely gets close to that line.