Ever wondered how your Tesla's battery is really doing? Just like any rechargeable battery, your Tesla's high-voltage battery will experience some degradation over time. This is a natural process, but understanding its health can help you optimize charging habits and ensure your vehicle performs at its best for years to come. Fortunately, Tesla provides a built-in "Battery Health Test" that gives you an indication of your battery's capacity compared to when it was new. Let's dive into how you can run this test and what to expect!
Step 1: Engage with Your Tesla's Inner Geek
Ready to uncover the secrets of your Tesla's battery? The first step involves accessing a special mode in your car's infotainment system. Don't worry, it's not as complicated as it sounds, and you won't break anything!
Sub-heading: Accessing Service Mode (for some models)
For certain Tesla models (like older Model 3/Y), you might need to enter "Service Mode" to find the battery health test. Here's how:
On your Tesla's touchscreen display, tap the Car icon in the bottom left corner.
Navigate to Software.
Press and hold the Model 3 (or Model Y, Model S, Model X) icon at the top of the software page.
A prompt will appear, asking for an access code. Type in "service" and press Enter.
You'll see a warning message: "This mode should only be used by personnel for repair or a stationary vehicle." Click Enable to proceed. Your screen will get a red border, and some vehicle functions might temporarily turn off.
Note: Newer software versions on some models might have moved this test to a more accessible location, potentially under "Controls > Service > Battery Health" without needing to enter the full "Service Mode" beforehand. Always check your specific model's owner's manual for the most up-to-date instructions.
Step 2: Prepare for the Test – The Pre-Flight Checklist
Before you initiate the battery health test, there are crucial conditions your Tesla needs to meet. Failing to meet these requirements will prevent the test from starting.
Sub-heading: Essential Requirements for a Successful Test
Make sure your Tesla ticks all these boxes:
Battery Level is Low: The vehicle's battery level must be 20% or less. Some sources suggest below 50% is sufficient, but lower is generally better for an accurate test. If your battery is too high, the test won't start.
Connected to AC Charging: Your Tesla must be plugged into an AC charging station. This means a Level 2 charger (like your Wall Connector or a public Level 2 charger), providing at least 5 kW of power. Supercharging is NOT supported for this test.
Vehicle in Park: Ensure your Tesla is securely in Park (P).
Internet Connection: Your vehicle needs to be connected to Wi-Fi or a cellular network for the test to communicate and retrieve necessary data.
No Active Alerts: There should be no active alerts related to the battery or thermal system.
No Pending Software Updates: Make sure there are no scheduled or pending software updates for your vehicle.
Pro Tip: If your battery is above 20%, you'll need to drive it down or let it sit unplugged until it meets the requirement.
Step 3: Initiating the Battery Health Test
Once all the conditions are met, you're ready to start the test.
Sub-heading: Navigating to and Starting the Test
From the Service Mode menu (if applicable), or directly from Controls > Service, locate the Battery section.
Select High Voltage, and you should see an option for Battery Health or Battery Health Test.
Click on Health Test or Start Test.
A pop-up will appear with important information about the test. Read it carefully.
To authorize the test, you may need to hold up on the turn signal stalk and press the brake pedal at the same time. Follow the on-screen prompts.
A message will confirm that the test is now unlocking and will begin shortly.
Step 4: The Waiting Game – What Happens During the Test ️
The Tesla Battery Health Test is not a quick process. It can take up to 24 hours to complete.
Sub-heading: What to Expect During the Test
Discharge and Recharge Cycle: During the test, your Tesla will discharge its battery to below 10% (potentially even to 0%) and then fully recharge it to 100%. This deep cycle helps the Battery Management System (BMS) get a precise reading of the battery's current capacity.
Heat and Noise: You might notice your vehicle producing heat and loud noises, such as the fans running at high speed. This is completely normal as the car manages temperatures during the intense charge/discharge cycle.
Disabled Features: Certain vehicle features, like Sentry Mode and climate controls, will be temporarily disabled during portions of the test.
Touchscreen Off: The touchscreen might turn off for certain segments of the test.
Do Not Unplug: It is crucial not to unplug your Tesla while the test is running. If you need to stop it, cancel the test on the touchscreen first.
Avoid Interaction: Tesla recommends avoiding interaction with the vehicle or the Tesla mobile app during the test to ensure accurate results.
Step 5: Understanding Your Results and What Comes Next
Once the test is complete, your Tesla's touchscreen will display a percentage that indicates your battery's health.
Sub-heading: Interpreting Your Battery Health Percentage
The percentage displayed reflects the energy retention of your vehicle's battery compared to when it was new.
95% – 100% (Excellent): Your battery is in superb condition with minimal degradation. No action needed.
85% – 94% (Good): This indicates normal wear and tear. You can optimize your charging habits to slow down further degradation.
75% – 84% (Moderate): Your battery is showing some notable degradation. Consider reviewing your charging and driving habits to improve battery longevity.
Below 75% (Poor): This suggests significant battery degradation. If the energy retention is affecting your vehicle's usability, it's recommended to schedule a service appointment with Tesla.
Important Note: While this test is a good indicator, various factors can influence its readings, such as the battery temperature during the test and your charging history. Tesla's battery management system constantly monitors and recalibrates, but this test provides a snapshot.
Factors Affecting Tesla Battery Health
Battery degradation is a natural process, but several factors can accelerate or mitigate it.
Frequent Supercharging: While convenient, frequent fast charging generates more heat, which can accelerate battery wear. Prioritize Level 2 AC charging for daily use.
Extreme Temperatures: Both consistently high heat and extremely cold temperatures can negatively impact battery life. Park in shaded areas in hot climates and in a garage in cold ones. Preconditioning your battery in extreme weather can help.
Charging Habits:
Avoid regularly draining the battery below 20%.
Avoid routinely charging to 100% for daily use. For everyday driving, aim to keep your battery between 20% and 80-90%. Only charge to 100% when you need the full range for a long trip.
Leave your vehicle plugged in when not in use. This allows the car's thermal management system to maintain optimal battery temperatures.
Driving Habits: Aggressive acceleration and high-speed driving put more strain on the battery. Smoother driving habits and utilizing regenerative braking can help preserve battery health.
Mileage and Age: As expected, batteries degrade over time and with more miles driven due to increased charge cycles. Tesla batteries typically retain over 80% of their original capacity even after 10 years or well over 100,000 miles.
10 Related FAQ Questions
How to check Tesla battery health percentage without the official test?
While the official test is the most accurate, you can get a rough idea by observing your estimated range at 100% charge compared to its original factory range. Third-party apps can also provide more detailed insights by analyzing your driving and charging data.
How to improve Tesla battery health?
To improve battery health, avoid frequent Supercharging, keep your daily charge between 20% and 80-90%, avoid deep discharges, park in moderate temperatures, and utilize regenerative braking.
How to use third-party apps for Tesla battery health monitoring?
Apps like Tessie and TeslaBat connect to your Tesla's data and provide detailed analytics on battery degradation, charging history, and more. You'll typically grant them access via your Tesla account.
How to know if my Tesla battery needs replacement?
If your battery health test consistently shows below 75% and you experience a significant and noticeable drop in range or performance that impacts usability, it's a strong indicator that your battery might need professional inspection or replacement.
How to tell if Tesla battery degradation is normal?
A typical Tesla battery degrades around 1% per year for the first 7 years or so, with an average retention of around 93% after seven years. Degradation can vary based on usage, but significant drops outside these norms might warrant concern.
How to access Tesla's built-in Energy app?
The Energy app is accessible directly from your Tesla's touchscreen and provides real-time energy consumption data and estimated range based on your driving habits.
How to interpret different Tesla battery warranties?
Tesla's battery and drive unit limited warranty typically covers 8 years or a certain mileage (e.g., 100,000 to 150,000 miles depending on the model), with a minimum of 70% battery capacity retention over the warranty period. Check your specific vehicle's warranty details in the Tesla app or owner's manual.
How to optimize charging habits for Tesla battery longevity?
For daily driving, set your charge limit to 80-90%. Only charge to 100% for long trips. Avoid letting the battery consistently drop below 20%. Keep your Tesla plugged in whenever possible when not in use.
How to schedule a Tesla service appointment for battery concerns?
You can easily schedule a service appointment through the Tesla mobile app. If your battery health is significantly degraded and impacting usability, this is the recommended course of action.
How to deal with extreme temperatures for Tesla battery health?
In hot climates, park in shaded areas or use cabin overheat protection. In cold climates, preconditioning your battery before driving and keeping it plugged in can help maintain optimal operating temperatures and reduce range loss.
For a visual guide on running the battery health test, check out this video:
