Battery capacity decreases with usage. The Battery Health feature helps you visualize and track it.
How does it work?
The Battery Management System (BMS) in your Tesla is continuously estimating how much energy is in the battery. Tessie collects capacity and range BMS estimates every time you charge 5 kWh or more so you can track the state of your battery.
Capacity is the "energy added" value displayed in your vehicle if you were to charge it from 0% to 100%. Likewise, max range is the value displayed in your vehicle if it was charged to 100%.
Since these measurements fluctuate, it's important to focus on the average and not a single data point.
If degradation or capacity looks unusually high or low
It's possible that the BMS calibration has drifted and its calculations are inaccurate. You can help it learn how much energy is in the battery by calibrating it.
Setting the original capacity
Tessie calculates the original battery capacity using data from other Tesla owners with your vehicle configuration. However, this calculation may be incorrect if Tesla has replaced your battery or changed manufacturing processes in the middle of a model year.
You can change the original capacity by pressing the number on the battery health gauge. Battery health will automatically recalculate.
If you have a new vehicle and your battery capacity is reading well above or below the fleet, it's indicative that Tesla has changed the manufacturing process for your configuration. You can find the correct value by changing the capacity until your measurements line up with the fleet average.
How can I minimize degradation?
Check out Minimizing Battery Degradation.
What amount of degradation is normal?
Capacity starts to decrease immediately, and tends to stabilize around a 10% loss. Some batteries degrade slowly and level off around 100,000 mi or 150,000 km, but others may degrade and level off much more quickly.
Why was there a sudden change in capacity or range?
This can happen if a vehicle has a configuration change that affects range, like changing wheel sizes, or when Tesla updates range via over-the-air updates.
When this happens, it's a good idea to calibrate the Battery Management System to help it relearn how much energy is in the battery.
How are charge cycles measured?
Charge cycles represent the number of times the battery has charged the equivalent of 0% to 100%. For example, charging from 80% to 90% ten times is one charge cycle.
For the time prior to Tessie tracking your charging data, Tessie estimates charge cycles using the vehicle's real-world energy usage patterns.
What happens if my battery gets replaced?
Tessie automatically learns your new battery. The health percentage, capacity and max range calculations will automatically begin adapting to the new battery. After 30 charges of 5 kWh or more, the calculations will be fully calibrated to the new battery.