Your Model Y's Battery Is Probably Fine. Here's How to Know, and How to Make a Buyer Believe It.

Two 2022 Model Ys. Same colour, same kilometres, same suburb. One battery holds 97% of its original capacity. The other holds 89%.

Nothing on the outside tells you which is which. The dashboards look identical, the test drives feel identical, and both sellers will say the battery is fine.

If you're selling a Model Y, that gap is your problem, because the buyer prices in the worst case. If you're buying one, that gap is the entire question. The good news is that Model Y battery health is one of the most measurable, most documented numbers in the used car market. Here is what's normal at your mileage, every way to check it, and the difference between knowing your number and being able to prove it.

What's normal for a Model Y battery

Start with the number Tesla itself publishes. According to Tesla's Impact Report data, Model 3 and Model Y Long Range packs lose about 15% of capacity on average after 200,000 miles, which is around 320,000 km. That is a decade of typical driving with 85% of the battery still there.

The shape of the curve matters as much as the endpoint. Degradation is front loaded. The steepest drop happens early, with fleet analyses showing several percent lost in the first year or two as the pack settles and the battery management system calibrates, then the curve flattens to roughly 1 to 2% a year in normal use. So a three-year-old Model Y showing 92 to 95% is not a worry. It's the curve doing exactly what the data says it does.

One myth worth killing while we're here: Supercharging is not eating your battery. Recurrent's analysis of Tesla fleet data found the difference in degradation between owners who fast charge almost exclusively and those who rarely do is statistically insignificant. If a buyer tries to discount your car because "it's been Supercharged," the data is on your side.

The warranty floor underneath you

Every Model Y carries an 8-year high voltage battery warranty with a 70% capacity retention floor. The distance cap depends on the variant: 160,000 km for RWD versions and 192,000 km for Long Range and Performance, which is 100,000 and 120,000 miles in US terms.

That 70% floor is worth explaining to a nervous buyer. For a pack to fall out of warranty coverage on capacity, it would need to degrade at roughly double the fleet average rate. Most Model Ys will retire from the road long before their battery gets anywhere near it.

One Model Y is not like another: the chemistry detail

Here's a genuinely Model Y specific wrinkle most guides skip. RWD Model Ys built in Shanghai, which includes the Australian-delivered RWD, use LFP battery chemistry. Long Range and Performance variants use nickel-based cells.

Why you should care: LFP packs are happy being charged to 100% regularly, and Tesla's own manual recommends it, because the flat voltage curve of LFP means the battery management system needs full charges to stay calibrated. A Shanghai RWD that has spent months bouncing between 30 and 60% can show a state of health reading that has drifted well away from reality. Which leads directly to the next problem.

How to check your Model Y's battery health

You have three real options, and I'll give you the honest version of each.

Tesla's built-in Battery Health Test. Since early 2025, the car can test itself: Controls, then Service, then Battery Health Test. It's free and it's official, and Tesla's own documentation sets out the catch. The car must be plugged into an AC charger supplying at least 5 kW, the test discharges the pack below 10% and then charges it to 100%, it can take up to 24 hours, climate control and Sentry Mode are disabled while it runs, and Tesla recommends running it only if you have a concern about the battery. You also get one test every six months unless you go digging in Service Mode. It's a genuine diagnostic, built for troubleshooting rather than selling. Which shows in the final catch: the result is a number on your touchscreen. When you list the car, that number becomes a photo of your own screen, and a photo of a seller's screen is exactly the kind of evidence buyers have learned to discount.

Third-party tracking apps. Tessie and similar apps read Tesla's data and estimate battery health over time. Useful for owners, genuinely. But the readings can drift, especially on cars charged in narrow windows, and I've written up a real case where an app showed 89.9% and the calibrated number came in around 83%. More fundamentally, an app reading has the same problem as the touchscreen: it lives in your account, on your phone, and a buyer cannot verify any of it.

An independent audit. This is what I built EV TrustSeal to do. You connect your Tesla account, read-only, through Tesla's own login. Drive as normal until the battery is under 20%, press Start Audit, plug in to AC at home, and the audit measures how much energy your pack actually delivers as it charges to 80%, straight from Tesla's cloud, no dongle and no workshop. Your result arrives within hours as a VIN-locked certificate with a QR code, and the buyer scans it and sees the record on our servers, not a screenshot on yours. Connecting is free. You pay the $99 only when your result is ready. In our own audits during testing, a 2026 Model Y measured 99% and a harder-driven 2023 Model 3 came in at 85.4%, both graded, dated and verifiable, which is the entire point.

What your number means when you sell

On an EV TrustSeal certificate, 95% and above grades Excellent and 85 to 94% grades Strong. Most Model Ys under five years old will land in one of those two bands, and both are sale-ready numbers: Excellent removes buyer hesitation entirely, and Strong shows verified, normal wear, which moves the negotiation to the car instead of the battery.

The sellers who lose money on Model Ys are almost never the ones with bad batteries. They're the ones with good batteries and no proof, negotiating against a buyer's imagination. A Model Y with a verified 96% and a Model Y with an unproven "it's fine" are the same car with different sale prices.

FAQ

What is normal battery degradation for a Tesla Model Y? Tesla's fleet data shows about 15% average capacity loss at 200,000 miles for Long Range packs. Expect the fastest drop early, then roughly 1 to 2% a year. A 3-year-old Model Y in the low to mid 90s is normal.

How do I check my Model Y's battery health for free? Use Tesla's built-in test under Controls, Service, Battery Health Test. Budget up to 24 hours, an AC charger of at least 5 kW, and a full discharge-recharge cycle. The result appears on your touchscreen.

Is Tesla's Battery Health Test accurate? Yes, it's a genuine calibrated measurement from Tesla's own diagnostics. Its limits are practical rather than technical: it's slow, limited to twice a year, and the result isn't independently verifiable by a buyer.

What battery health should I look for when buying a used Model Y? Above 90% is comfortable for most cars under five years old. Below the mid 80s, ask about charging history and price accordingly. Whatever the number, insist it comes from something you can verify yourself, not the seller's screen.

Does Supercharging damage the Model Y battery? Fleet analysis by Recurrent found no statistically significant difference in degradation between frequent and rare Supercharger users. Charging habits matter less than the internet says.