Battery Health Metrics for Electric Fleets
Learn how monitoring battery metrics can enhance the lifespan and efficiency of electric fleets, reducing costs and improving performance.
Electric fleet operators can extend battery life, cut costs, and improve efficiency by monitoring key metrics like State of Charge (SOC), State of Health (SOH), and charging cycles. Here's what you need to know:
- Battery degradation has slowed, with rates dropping from 2.3% annually in 2019 to 1.8% in 2024. Most EV batteries now last 15–20 years under moderate use.
- SOC and SOH are critical metrics. Keep SOC between 20–80% to reduce wear, and track SOH to plan maintenance or replacements.
- Charging habits matter. Avoid frequent DC fast charging; use Level 2 charging overnight to prolong battery life.
- Telematics systems enable real-time monitoring of battery health, temperature, voltage, and current, helping prevent costly breakdowns.
- Regulations like Euro 7 now require EV batteries to meet capacity retention standards (e.g., 80% capacity after 5 years or 100,000 km for cars).
What is a Battery Management System BMS? EV Range Prediction, Charging, Safety
Key Battery Health Metrics to Track
Keeping an eye on the right battery metrics is essential for ensuring your electric fleet runs smoothly. These indicators give you the insights needed to make smart decisions about charging, maintenance, and how to deploy your vehicles. They’re the foundation for using telematics to create effective maintenance and operational plans.
State of Charge (SOC) and State of Health (SOH)
State of Charge (SOC) measures how much usable energy is left in a battery, acting like a fuel gauge for EVs. Extreme SOC levels - either too high or too low - can lead to faster battery wear and reduce its usable capacity. Ideally, you should aim to keep the SOC between 20% and 80%. Staying within this range helps minimise wear and can significantly extend the battery’s lifespan.
State of Health (SOH), on the other hand, tells you about the overall condition of a battery and how much of its original capacity remains. Expressed as a percentage, a brand-new battery starts at 100% SOH. As SOH drops, so does the battery’s performance. For example, a battery at 80% SOH will only deliver 80% of the range it could when new. Tracking SOH allows you to anticipate potential failures, schedule timely maintenance, and adjust operations to make the most of the remaining battery life. With EV batteries degrading at an average rate of 1.8% per year, keeping an eye on SOH also helps you plan replacements and budget for them effectively.
Next, let’s look at how charging cycles affect battery health.
Charge/Discharge Cycles and Depletion Rates
Each full charge and discharge cycle contributes to the natural wear of a battery. By tracking how often these cycles occur and the conditions under which they happen, you can spot vehicles that might be undergoing faster-than-usual battery wear. Depletion rates can vary due to factors like driving habits, vehicle load, and environmental conditions. Monitoring these rates across your fleet helps identify vehicles experiencing higher battery strain, allowing you to adjust maintenance schedules and optimise vehicle usage.
Temperature, Voltage, and Current Monitoring
Temperature plays a huge role in battery health. High temperatures can shorten battery life, while low temperatures can reduce the battery’s usable capacity and energy output. The type of cooling system also matters: liquid cooling systems are generally better at preserving battery life compared to passive air cooling systems. For instance, the 2015 Tesla Model S, which uses liquid cooling, has a degradation rate of 2.3%, whereas the 2015 Nissan Leaf, with air cooling, degrades at 4.2%.
Monitoring voltage and current is equally important. Overcharging or excessive discharge can damage battery cells, so keeping these parameters in check helps protect the battery. This kind of monitoring not only extends battery life but also aligns with environmental priorities that are particularly important for fleet managers in the UK.
Telematics systems make it easier to track and analyse data on battery performance, condition, and usage in real time. By identifying anomalies early and implementing predictive maintenance, you can prevent costly breakdowns and extend the operational life of your fleet. These tools also help you stay ahead of potential issues, ensuring your EVs remain safe and efficient on the road.
What Causes Battery Degradation
Understanding what leads to battery wear and tear is essential for making smart decisions about fleet deployment and upkeep. These factors can be grouped into two main categories: environmental conditions and how the vehicles are used. Let’s break it down.
Weather and Climate Effects
The UK's famously unpredictable weather poses a challenge for EV batteries, which perform best in temperatures between 15°C and 45°C. When the mercury rises above 30°C, degradation speeds up. For example, at 35°C with the air conditioning running, an EV's range can drop by as much as 17%. On top of that, the UK's high humidity levels - thanks to its maritime climate - can lead to corrosion, further shortening battery life.
Usage Patterns and Maintenance
How an EV is driven and maintained also plays a huge role in battery health. Fleet vehicles, which often face more demanding conditions than privately-owned cars, tend to experience faster battery degradation. Aggressive driving habits, like sudden acceleration and hard braking, not only reduce range but also wear down the battery more quickly. Studies show that under heavy use, EV batteries can lose between 3% and 13% of their capacity over three years.
The good news? Adjusting driving habits can make a difference, with smarter driving potentially boosting range by about 15%. However, neglecting maintenance can speed up the degradation process. Without regular health checks and proper thermal management, small issues can quickly snowball. James Fisher, CEO of Gecko Risk, highlights the importance of collaboration in tackling these challenges:
"Responding to battery longevity requires enhanced data understanding and collaboration across the mobility sector – between insurers, fleets, repairers, and OEMs. This action is crucial for meeting Government mandates."
Finally, high-mileage operations, such as those in delivery and logistics, naturally age batteries faster due to the increased number of charge–discharge cycles. Keeping these factors in mind is key to maximising battery life and efficiency.
How to Monitor and Extend Battery Life
Once you've identified key battery metrics, the next step is implementing strategies to prolong battery life. Keeping a close eye on battery performance and practising smart upkeep can make all the difference when it comes to extending fleet battery life.
Using Telematics for Battery Health Monitoring
Telematics systems offer real-time insights into battery health, charging habits, and overall performance. This data allows fleet managers to detect potential problems early, avoiding costly repairs or replacements.
Charlotte Argue, Senior Manager of Sustainable Mobility at Geotab, underscores the role of telematics in fleet management:
"Telematics data is crucial for understanding the health of your fleet's EV batteries. With EV fleet management solutions, you can monitor real-time battery capacity, track degradation rates and make data-driven decisions to extend vehicle life."
GRS Fleet Telematics is one such platform that integrates directly with electric vehicle systems. It tracks crucial metrics like state of charge, temperature variations, and charging patterns. This information equips managers with actionable insights to optimise battery performance across the fleet.
The real strength of telematics lies in its ability to predict maintenance needs. By identifying subtle changes that hint at possible issues, it allows for proactive maintenance instead of waiting for problems to arise.
Some of the latest telematics platforms even include AI-powered analytics, which turn complex battery data into easy-to-understand visualisations and forecasts. While monitoring is vital, adopting better charging habits can further enhance battery life.
Better Charging Practices
Data-driven insights can help refine charging habits, which are critical for maintaining battery health. For instance, following the 20–80% rule - keeping the battery's state of charge within this range - reduces stress on the electrodes and extends the battery's lifespan.
For everyday use, Level 2 charging is recommended because it’s gentler on batteries compared to DC fast charging. Research by Kia found that using standard charging for eight years can result in 10% more battery life than relying solely on fast charging.
Matthew Lum, an Automotive Engineer at AAA, highlights the factors that can degrade battery health:
"Factors that can negatively impact battery health include charging behaviour, charging current, temperature, time, and number of charge and discharge cycles."
Automotive journalist Jess Shanahan adds:
"Typically, the quicker the charge, the more stress on the battery. If a car was to be charged on a regular basis with only high-speed chargers, it might lose more battery capacity than one that was only ever charged slowly at home."
To protect battery health, consider automating charge limits to enforce the 20–80% rule, reserving full charges for longer trips. Additionally, smart charging management can help reduce costs. By scheduling charges during off-peak electricity rates, fleets can cut charging expenses by as much as 62%.
Climate Protection and Maintenance Strategies
Charging habits aren’t the only factor affecting battery life - temperature control plays a big role too. Batteries degrade faster in extreme temperatures, so managing environmental conditions is essential.
Whenever possible, park vehicles in areas with moderate temperatures. This simple step can significantly slow down battery wear compared to leaving vehicles exposed to extreme heat or cold. For fleets operating in harsher climates, vehicles equipped with advanced thermal management systems are worth considering.
On top of automated telematics monitoring, regular physical inspections are crucial. These checks can uncover issues like cooling system failures or charging port damage before they start impacting battery performance.
Geotab’s analysis shows how battery durability has improved over time, with average degradation rates dropping from 2.3% per year in 2019 to 1.8% per year in 2024. For fleets that cover high mileage, it’s best to avoid frequent DC fast charging. Instead, rely on overnight Level 2 charging to meet daily needs. This approach is particularly effective for delivery and logistics fleets that return to the depot each evening.
UK Regulations and Battery Health Standards
The rules surrounding EV battery health are shifting, aiming to bring more clarity, safeguard consumers, and boost trust in the market. These changes are particularly relevant for fleet operators, who must now keep a closer eye on battery performance data and report it accurately. A major step in this direction is the introduction of the EU's Euro 7 standards.
The EU's Euro 7 standards, effective from 1st July 2025, set clear benchmarks for battery electric vehicles (BEVs) and plug-in hybrid electric vehicles (PHEVs). These standards require car batteries to retain at least 80% of their energy storage capacity after 5 years or 100,000 km and 72% after 8 years or 160,000 km. For light commercial vehicles, the thresholds are slightly lower at 75% and 67%, respectively, over the same periods.
"Europe has implemented that with the Euro 7 proposals. The UK Government is still considering UK implementation and options and what it might mean for us."
Another key development is the United Nations Global Technical Regulation No. 22, which sets worldwide benchmarks for EV battery performance and monitoring. This regulation mandates that EVs include systems to track the state of certified energy (SOCE) and state of certified range (SOCR), with limits on how much energy capacity can fade over time. These measures align with the need for consistent and thorough battery health analysis, including metrics like state of charge (SOC), state of health (SOH), and temperature monitoring.
From February 2027, the European Commission will require all EV batteries sold to come with a digital battery passport. This passport will provide detailed information about the battery's specifications and lifespan, accessible through a QR code.
Manufacturer Warranties and Coverage
Most vehicle manufacturers offer battery warranties covering up to eight years or 160,000 km (around 100,000 miles), whichever comes first. These warranties are a financial safety net for fleet operators, especially since replacing a battery can cost up to 30% of a vehicle's total price.
Battery warranties play a critical role in addressing consumer concerns about durability. Research shows that 47% of drivers worry about battery lifespan, and 56% overestimate the severity of range loss - believing it’s three times worse than it actually is. This disconnect between perception and reality can affect residual values and leasing rates, making strong warranty coverage essential for fleet planning.
"For both sets of buyers, what a state of health check (SoH) provides is a high level of reassurance that the battery in the used car they are considering is in good condition, has been well looked after, and is not about to fail."
The UK is also exploring a standardised battery health certification for used EVs, similar to Norway’s model. This certification would independently verify battery condition, and buyers have shown a willingness to pay between €550 and €1,100 more for used EVs with such a health check certificate.
Meeting Compliance Requirements
Beyond warranty terms, regulatory compliance now demands stricter battery performance tracking. Fleet operators are under growing pressure to meet these requirements, including those outlined in the ZEV Mandate, which integrates minimum performance standards for EV batteries into UK law. The UK is also closely watching EU proposals for mandatory battery state-of-health monitors in new EVs.
"GTR 22 provides the requirement for a battery state of health monitor which is in an easily accessible manner, such as through the vehicle's dashboard."
Additionally, fleet operators must maintain detailed lifecycle records for EV batteries. From February 2025, EV batteries sold in the EU will need a carbon footprint tied to their manufacturing site and batch. By 2031, batteries must include minimum recycled material percentages - 16% cobalt, 85% lead, 6% lithium, and 6% nickel from recycled sources. Operators will also need to conduct supply chain assessments to address social and environmental risks. Furthermore, battery owners must be provided with health data to evaluate options for reuse, repurposing, or recycling.
"Consumer confidence in the second-hand market is currently being undermined by uncertainty and concerns about EV battery health."
To meet these demands, fleet operators must adopt advanced telematics systems for battery monitoring and prepare for the rollout of battery passports. These measures not only ensure compliance but also support the broader shift towards electric mobility.
Connecting Battery Health Data with Fleet Telematics
Once the key battery metrics are identified, linking this data with telematics can streamline fleet operations significantly. Modern telematics platforms now provide detailed, real-time insights into battery performance, charging habits, and overall efficiency. With batteries accounting for 30–50% of an electric vehicle's cost, monitoring them effectively becomes crucial. This integration not only safeguards a fleet's most expensive component but also enables smarter, more cost-effective maintenance strategies.
Benefits of Battery Data Integration
Proactive battery monitoring, when combined with telematics, takes fleet management to the next level. By integrating battery data, fleet managers gain access to predictive maintenance capabilities, helping to minimise breakdowns and reduce costs. Real-time insights into metrics like charge levels, range, and overall battery condition empower managers to act quickly. As Team ChargePoint notes:
"By implementing predictive maintenance practices and analysing battery performance trends, early warning signs of potential failures can be identified and addressed promptly."
Continuous monitoring of factors like temperature, charging habits, and driver behaviour allows managers to spot patterns that may lead to faster battery wear. This enables them to take corrective actions early, avoiding larger issues down the line. Additionally, tailored charging schedules can be created to suit each fleet's unique needs, helping to sidestep peak electricity rates while preserving battery health. Real-time data also supports better route planning and targeted driver training, which collectively extend battery lifespan and boost operational efficiency.
GRS Fleet Telematics for Battery Monitoring
GRS Fleet Telematics offers a specialised solution for UK businesses, providing comprehensive battery monitoring and fleet management for just £7.99 per month.
The platform enables real-time tracking of key battery health metrics, giving fleet managers the ability to oversee charge levels, temperature variations, and performance indicators across their entire electric fleet. This continuous oversight helps identify potential problems before they disrupt operations, encouraging a proactive maintenance approach.
In addition to battery monitoring, the system includes driver safety tools such as speed tracking, geofencing, and eco-driving analytics. These features allow managers to implement driver training programmes that encourage efficient driving habits, ultimately extending battery life. With 24/7 recovery support, dedicated account management, scalable solutions for fleets of all sizes, and white-label branding options, GRS Fleet Telematics provides a robust solution for UK businesses transitioning to electric fleets while ensuring operational efficiency and protecting their substantial investment in batteries.
Conclusion
Keeping an eye on battery health metrics is a game-changer for electric fleet operations. Effective monitoring can cut fuel costs by up to 45% and ensure fleet uptime stays as high as 99%. It also extends the life of batteries, with some lasting over 20 years when properly maintained.
Telematics solutions play a big role in shifting battery management from merely reacting to problems to preventing them in the first place. As Ekoenergetyka highlights:
"By offering a comprehensive view into the health and usage of EV batteries, this technology makes fleet operations smarter, more efficient, and cost-effective".
This proactive approach helps identify potential issues early, avoiding expensive breakdowns and aligning with the broader benefits of telematics in fleet management.
GRS Fleet Telematics offers a cost-effective option for UK businesses at just £7.99 per month. It combines detailed battery monitoring with driver safety tools and 24/7 recovery support. With features like tracking charge levels, monitoring temperature fluctuations, and analysing performance data across fleets, it supports the predictive maintenance strategies modern electric fleet operators need.
To get the most out of EV batteries, fleet operators should focus on best practices like charging within the 20–80% range, implementing thermal protection, encouraging efficient driving habits, keeping software updated, maintaining chargers regularly, and planning routes strategically.
FAQs
How do telematics systems support monitoring and maintaining the battery health of an electric fleet?
Telematics systems play a crucial role in keeping the batteries of electric fleets in good shape. By gathering real-time data on battery performance, these systems let fleet managers track important metrics like temperature, charge cycles, and degradation rates. With this information, potential problems can be spotted early, allowing for timely maintenance and lowering the chances of unexpected breakdowns.
They also offer valuable insights into charging behaviours and external factors that might affect battery life. By fine-tuning charging schedules and keeping an eye on environmental conditions, fleet managers can help batteries last longer, enhance vehicle performance, and cut down on operating expenses. This keeps the fleet dependable and economical in the long run.
What are the best charging practices to maximise the lifespan of electric vehicle batteries in a fleet?
To get the most out of your fleet's EV batteries, adopting thoughtful charging habits is key. One important tip is to limit the use of fast charging. While it’s convenient, frequent fast charging can speed up battery wear and tear. Instead, try to keep the battery charge level between 20% and 80%, as this range helps reduce strain on the battery.
Temperature control is another essential factor. Extreme heat or cold can take a toll on battery performance and lifespan, so try to park vehicles in environments with moderate temperatures whenever possible. These simple steps can go a long way in keeping your fleet's batteries running efficiently and reliably for a longer time.
How do environmental conditions and driving behaviours affect the lifespan of EV batteries?
How Environmental Factors and Driving Habits Affect EV Battery Life
The environment, especially temperature, has a big impact on how long EV batteries last. High temperatures can speed up battery wear, while cold weather might cause a temporary dip in performance but usually doesn’t cause lasting damage. To keep your battery in good shape, it’s important to maintain a steady, moderate temperature.
Your driving habits matter too. Things like frequent rapid charging, hard acceleration, and driving at high speeds can put extra strain on the battery over time. On the other hand, smoother driving, limiting rapid charging, and keeping the battery at an optimal temperature can go a long way in preserving its lifespan.