Every Model Y owner eventually asks the same question: "How much has my battery degraded?" In its 2025.8.3 software update released in March 2025, Tesla introduced a new feature that can test your car's battery health. Here is a comprehensive guide to using this feature.
1. What the Heck Is the Battery Health Test?
“a percentage that reflects the energy retention of your vehicle's Battery compared to when it was new.”
Your battery will naturally lose some capacity over time (totally normal). How fast it happens depends on:
- Age of the battery
- How you drive (flooring it every stoplight = faster degradation)
- Charging habits (daily 100 % charges, lots of Supercharging, etc.)
- Temperature extremes and how you store the car
Not every Model Y has this feature yet – if you don’t see it under Controls > Service, your car isn’t equipped.
2. When Should You Actually Run It?
Tesla’s exact words: Only run it if you’re genuinely worried about range loss.
This test is a pain (up to 24 hours, drains the battery to ~0 %, kills climate control). Don’t do it “just to check.”
3. Prerequisites – All of These Must Be True
You can’t start the test unless:
- You’re plugged into an AC charger delivering at least 5 kW (your 240 V home charger is fine; Superchargers do NOT work)
- Car is in Park
- No software updates pending (install them first)
- Battery is under 20 % (ideally drive it down to ~10 % before starting)
- Zero active battery or thermal warnings (anything that starts with BMS_ or VCFRONT_ = no-go)
If any of these conditions are not met, your car will give you an alert screen like below:
4. How to Run the Test (Step-by-Step)
- Plug in at home or a Level 2 charger
- Touch Controls > Service > Battery Health Test
- Read the warning pop-up and hit Start Test
That’s it. Now walk away.
5. What Happens During the Test?
The test takes up to 24 hours to run. While the test is running, the touchscreen displays a progress bar and the estimated time remaining. The touchscreen will be off for certain portions of the test, the Battery will be discharged below 10% (and may be discharged as low as 0%), and vehicle features (such as Sentry Mode and climate controls) are disabled.
⚠️ Serious warnings
- Do NOT leave people or pets in the car (no A/C or heat)
- Don’t keep opening the Tesla app or poking the car
- If you have to unplug for any reason, **cancel the test first** in the app or on screen
When it finishes, the car automatically starts charging back to your normal limit.
6. Reading the Results
As soon as it’s done you’ll see something like:
Battery Health: 93 % (compared to when the car was new)
Your displayed range may also jump up or down a bit because Tesla recalibrates the guess-o-meter to match the real capacity.
If the result is way outside what Tesla expects for your car’s age and mileage, it’ll gently suggest making a service appointment.
7. When Can You Run It Again?
After you finish one test, the button goes gray for months. It only becomes available again when the battery management system detects a meaningful change in capacity (usually 6–12 months later).
Bottom Line for North America Owners
- 99 % of the time you do **not** need to run this test.
- If your 2022–2023 Model Y with 40–60 k miles is still showing 260–280 miles at 100 %, you’re totally fine.
- Only run it if you legitimately feel like you’ve lost a huge chunk of range compared to last year.
