Battery health explained

Battery health is one of the most important metrics for any electric vehicle. Here is how to read yours.

Key metrics

Battery Level vs. Usable Battery

• Battery Level is what Tesla displays on the dashboard, the percentage shown on your screen
• Usable Battery is the actual amount available for driving, which is slightly lower due to buffer reserves. Tesla reserves a small portion of total capacity to protect the cells from deep discharge, extending overall battery life

State of Health (SoH)

SoH is the single most important number for assessing long-term battery condition. It shows what percentage of the battery's original capacity remains. For example, a 75 kWh battery pack with 95% SoH has roughly 71.25 kWh of usable capacity.

SoH is included in every report.

Battery Capacity (kWh)

The current energy capacity of your battery pack in kilowatt-hours. Compare this against the original factory capacity to understand how much energy your battery can still store.

Range estimates

Tesla provides three different range figures, each calculated differently:

• Rated Range - Based on Tesla's EPA or WLTP rating for your model at the current charge level. This is the "official" number.
• Ideal Range - Estimated range under ideal conditions: moderate speed, flat terrain, comfortable temperature, no heavy loads.
• Estimated Range - A more conservative figure based on your actual recent energy consumption. This is usually the most realistic for daily use.

The gap between rated range and estimated range often widens as the battery ages, since rated range is based on a new battery's performance.

Charge Limit

Your configured maximum charge percentage. Tesla recommends:

• Daily driving: 80-90% to minimize wear on the cells
• Long trips: 100% only when you need the full range
• Storage: 50-60% if the car will sit unused for an extended period

Fast Charger Information

Your report shows whether a DC fast charger is connected and details about it:

• Charger type - Supercharger, CCS, CHAdeMO
• Charger brand - Tesla, Ionity, etc.
• Charging power - Current power delivery in kW
• Voltage and current - Electrical details of the charging session

What affects battery health?

• Age - All lithium-ion batteries degrade over time, even without use, due to chemical aging
• Mileage and charge cycles - Each full charge-discharge cycle causes incremental capacity loss
• Charging habits - Frequent DC fast charging (Supercharging) and regularly charging to 100% accelerate degradation by stressing the cells at high voltage
• Temperature - Extreme heat accelerates chemical degradation; extreme cold temporarily reduces available capacity. Tesla's thermal management system mitigates this but cannot eliminate it entirely
• Usage patterns - Aggressive acceleration and sustained high-speed driving increase thermal stress on the pack

Is my battery healthy?

A small amount of degradation is completely normal and expected.

General guidelines:

• Above 95% SoH - Excellent condition
• 90-95% SoH - Normal for a vehicle with moderate mileage
• 85-90% SoH - Typical for high-mileage or older vehicles
• Below 85% SoH - Worth investigating. Consult a Tesla service center if the degradation seems excessive for your vehicle's age and mileage

Tesla's battery warranty covers significant capacity loss (typically below 70% within the warranty period).

Why do range estimates differ from real-world range?

Several factors cause the displayed range to differ from actual driving range:

• Speed - Highway driving at 120 km/h uses significantly more energy than city driving at 50 km/h
• Weather - Cold weather can reduce range by 20-40% due to battery heating and cabin heating
• Elevation - Climbing hills uses more energy (though descending recovers some via regenerative braking)
• Payload - Extra passengers and cargo increase energy consumption
• HVAC - Air conditioning and heating draw from the battery
• Tire pressure - Under-inflated tires increase rolling resistance and reduce range