EV Performance

Battery State of Health is a measure of how much the EV battery has degraded since it was new, calculated from crowd-sourced baseline data.

Battery State of Health = (usable battery capacity) / (original usable battery capacity).

Usable battery capacity is calculated for each specific vehicle. It is Geotab's estimate of how much energy the battery can store, based on recent driving and charging events. One month of regular driving and charging is typically enough to generate a usable battery capacity estimate.

Original usable battery capacity is crowd-sourced from all vehicles with the same make, model, year, and trim. The calculation of original capacity requires low odometer data from many different vehicles. Crowd-sourcing original capacity information allows Geotab to calculate the State of Health of a vehicle, even if that vehicle was not connected when it was new.

When the State of Health is blank, it is likely because original capacity data is missing. The most common reasons for missing original capacity are:

• There is not enough crowd-sourced low odometer data for vehicles of the same make, model, year, and trim.
• The VIN number for this vehicle cannot be decoded. VIN is used to determine make, model, year, and trim.

Short-term fluctuations in reported battery capacity are normal and caused by temperature and software factors, separate from long-term degradation.

Temperature matters: Similar to how a phone battery drains faster in the cold, EV batteries are also affected by temperature. In colder weather, the chemical reactions inside the battery slow down, meaning it naturally has less usable energy, so the system reports a lower capacity. When it gets warmer, the battery performs better, and the reported capacity goes back up. Seasonal variation is normal and does not mean that the battery is getting better or worse in the long run.

Software buffers: Vehicle manufacturers use software buffers to protect the battery and extend its life. The vehicle's computer does not allow drivers to charge the battery to its full, physical capacity; the vehicle computer protects the battery by restricting the amount of energy drivers can store and use. Since usable battery capacity measures energy available to the driver, the vehicle's battery management software can influence the measurement. It is possible that usable battery capacity could change after a vehicle software update.

Short-term ups and downs (caused by temperature fluctuations or vehicle software updates) are different from the gradual, long-term degradation that naturally occurs in all batteries over time. Tracking battery health over several years is recommended to understand its true aging.

Range Capability is the distance a vehicle can drive on a single full charge, expressed as a range estimate that accounts for uncertainty in real-world driving conditions.

Range Capability is the distance a vehicle can drive on a single full charge.

EV range can be impacted by a number of factors, including weather, speed, altitude change, payload, and driving style. Because these factors are constantly changing, it is difficult to characterize EV range with a single value.

EV Performance displays range estimates in the form XX +/- YY, where:

• XX is the most likely range capability of this vehicle, based on recent trips.
• There is a 90% probability that the true range capability lies between XX-YY and XX+YY.

Use the groups filter in EV Performance to compare battery capacity and range capability across different vehicle makes and models.

Use groups to assess the performance of different types of EVs. For instance, if one group contains Model A and another contains Model B, use the groups filter to explore the performance of each group. The summary charts at the top of the EV Performance page display the average battery capacity and range for the selected group.