EV TELEMATICS: 7 KEY PERFORMANCE INDICATORS TO TRACK

Global electric vehicle (EV) adoption rate continues to grow, with China and Europe leading the move towards fleet electrification. In fact, according to ACEA, in May 2026, 20% of all newly registered vehicles in Europe were battery-powered and 40% were hybrid vehicles, indicating a gradual shift away from fully fuel-powered cars. This automotive transition indicates that fleet management practices need to adapt as well by focusing on EV fleets. As modern vehicles make the work of telematics solution providers easier by collecting a wide range of performance indicators useful in daily fleet operations, the question is what parameters matter and how to access this valuable vehicle data?

EV BATTERY MONITORING: WHAT FLEET MANAGERS SHOULD TRACK

For the owners of fuel-powered cars, regular maintenance and refuelling are among the main expenses. With fuel prices rising in 2026, monitoring fuel consumption has become a key focus of many telematics solutions implemented for the fleets of this type. Meanwhile, for EV owners, the ultimate concern is the risk of battery degradation and its costly replacement.

Depending on the vehicle model and the country, a new battery can cost between USD 7,000 and 15,000. Thus, an unexpected battery issue can turn into a substantial cost for businesses operating EV fleets. That’s why telematics solutions for electric vehicles should centre on batteries, their performance during rides, and charging process.

The key indicators for EV fleet managers to monitor are:

• State of health (SOH)

• State of charge (SOC)

• Temperature

• Charging speed

• Charging time and location

• Driver performance

State of health (SOH) is a natural starting point. It shows the difference between the battery’s original and current capacity. For example, if SOH is equal to 100%, the battery can be charged to its full capacity as designed by the manufacturer. Meanwhile, if SOH is 70%, it means that the battery has lost 30% of its original capacity, even when fully charged. It affects vehicle range and indicates the level of battery degradation.

However, SOH will not tell you what causes the degradation process. Fleet managers need more context to identify negative patterns and prevent further degradation. Monitoring state of charge (SOC) dynamics helps both minimise vehicle downtime during each trip and extend battery life. It is recommended to avoid regular full charges and discharges, with the optimal charging level being between 20% and 80%.

Next, battery performance is affected by temperature as extreme cold or heat can accelerate battery degradation and reduce vehicle range. Overheating is especially dangerous, with rare cases potentially leading to hazardous thermal events and putting the vehicle, the driver, and others nearby at risk. The optimal temperature range for EV performance is between 10°C and 30°C.

In addition to temperature, battery's charging speed is another important parameter to monitor. Depending on the region you operate, slow chargers still represent from 60% to 80% of the publicly available charging infrastructure. For many fleet owners, charging an EV may require several hours, with the exact time depending on the vehicle model and the temperature during charging.

As it is not very time-efficient, direct current (DC) fast chargers started gaining popularity in Europe, USA, and China, allowing to charge a car fully in around 20 minutes. Despite the convenience, the frequent use of DC chargers negatively impacts the battery and accelerates its degradation. While operating an EV fleet, it is worth monitoring vehicle charging speed and plan slow charging sessions whenever possible.

Charging time and location are also important to consider as they can affect costs. DC fast charging is typically the most expensive option, but there’s more to bear in mind. An increasing number of European countries introduce dynamic electricity pricing, meaning that charging during peak hours can cost up to 30% more than at night.

Finally, driver performance is just as important for electric vehicles as it is for fuel-powered cars. Harsh breaking and acceleration, regular speeding, and idling create unnecessary pressure on a vehicle and wear out its battery. Creating driver scores, identifying inefficient driving behaviour, and addressing it with individual drivers can help extend vehicle lifespan.

HOW TO MONITOR EV CHARGING WITH OBD DEVICES

Modern vehicles can easily be called computers on wheels. In fact, a single car can have 70 to 100 microcontrollers that manage internal systems such as the engine, breaks, airbags, and many others. Tapping into the CAN bus network, which transmits data between these microcontrollers, gives fleet managers a more complete picture of vehicle performance. The easiest way to access this data is by using an OBD device connected to the vehicle’s diagnostics port. It does not require professional installation and does not compromise vehicle warranty.

Teltonika’s OBD DATA category devices are tailored for monitoring light electric vehicles. Supporting more than 170 EV models allows reading all the key battery performance parameters listed above. Also, our trackers feature eco driving scenario to evaluate driver performance by detecting such events as cornering, harsh braking, and acceleration. What is more, with the latest firmware update, you can focus on the charging process when the vehicle battery is especially vulnerable. How does it work?

Teltonika’s devices can be configured to collect different sets of parameters depending on whether the vehicle is charging or not. Once charging starts, data collection changes to provide additional battery performance parameters. Besides state of health, state of charge, and real-time location, our trackers read the following data:

• Overall temperature and temperature range per each cell. Electric battery is composed of separate cells that are connected in series. Over time, differences in voltage and state of charge can develop between these cells. As a result, they might start charging with different speed and some might overheat while others stay within the acceptable range. That’s why looking into the individual cell temperature is as important as measuring average battery temperature.

  
  

• Battery voltage and current. The spikes of these parameters can be the markers of battery malfunction and alert about the risks of thermal events, which are especially dangerous when the vehicle is charging. Detecting overvoltage helps fleet operators plan vehicle maintenance in advance and reduce the risk of costly battery replacement.

  
  

• Maximum and current measured battery energy. It allows calculating how much energy the vehicle needs before it is fully charged. With this data, fleet owners can estimate how long an EV will take to charge and, accordingly, schedule charging sessions efficiently to reduce downtime and optimise fleet utilisation.

  
  

• Slow and fast charge counts. These parameters help track how often fast charging is used to make sure the battery is not subject to excessive stress.

This approach to EV monitoring allows fleet operators to focus specifically on the charging process, helping reduce the risk of unexpected battery issues and vehicle downtime. The availability of this functionality may vary depending on the vehicle model. Learn more about EV charging monitoring, including configuration and limitations, in our Wiki documentation.

Interested in further exploring EV management? Read our use case Advanced EV battery monitoring with OBD data reading devices.