About Battery Health
Tessie’s Battery Health features help you track your vehicle's battery performance over time.
How to view battery health
Visit Battery Health or tap Battery and the heart icon in the app.
How health tracking works
Your vehicle’s Battery Management System (BMS) estimates battery range and capacity.
Tessie records these fluctuating measurements after each charge of more than 5 kWh.
How range health is measured
Health = Current capacity ÷ Original capacity
Example: 300 mi now ÷ 400 mi when new = 75% health (25% degradation)
Tessie bases health on actual battery capacity, not the vehicle's displayed range, which can change with software updates, tires, and settings.
How range health compares to Tesla's battery health test
Tessie compares your current range to the original range when new. The Tesla battery health test does the same, but may further lower the result based on battery age.
How charge cycles are measured
1 cycle = one full charge from 0–100%
Example: charging 80–90% ten times = one cycle
Tessie estimates past cycles from your vehicle’s real-world energy usage and becomes more accurate as more data is collected.
How the original capacity is determined
Tessie uses the average new capacity for vehicles like yours, then updates it as more data becomes available from other users.
You can also set the original capacity yourself by selecting the number on the health gauge. Battery health will recalculate automatically.
What degradation is normal?
Batteries start losing capacity right away and often stabilize around a 10% loss. The rate depends on the specific battery type in your vehicle.
How can I minimize degradation?
See Minimizing Battery Degradation for tips.
Why did I see a sudden change?
This can happen after a configuration change (like wheel size) or a Tesla firmware update. When this happens, it’s a good idea to recalibrate the BMS.
If the battery is replaced
Use the Set Battery Date button and enter the installation date of the new battery. Tessie will recalculate health using data from the replacement.
If calculations look unusually high or low
The BMS may need calibration. Recalibrating can improve accuracy.