Testing battery health is essential to ensuring EVs are safe, reliable and maintain high levels of performance over time. The top three reasons to test the health of an EV battery can be grouped as follows:

1. Performance Optimization and Longevity: Assessing remaining capacity helps optimize the vehicle's performance and adapt driving or charging habits to extend the battery’s lifespan. Regular testing allows for better energy management and prevents premature degradation.
2. Safety and Reliability: Testing ensures the battery is operating safely, identifying potential risks like overheating before they become serious. Predicting when a battery might need replacement ensures reliability and avoids unexpected breakdowns.
3. Financial and Resale Value Considerations: Understanding the battery’s condition helps in planning for future expenses, such as replacement costs. A healthy battery report can enhance the vehicle's resale value, and regular testing ensures it remains within warranty coverage if applicable.

EV batteries can fail or degrade for several reasons, primarily due to the nature of lithium-ion technology and the demanding conditions under which these batteries operate. Here are some common causes of EV battery failure:

1. Degradation from Charge/Discharge Cycles: Every time an EV battery is charged and discharged, it undergoes wear and tear. Over many cycles, this can lead to the degradation of the battery’s internal components, reducing its capacity and efficiency. Frequent deep discharges and full charges can accelerate this process.
2. Thermal Stress: High temperatures can cause significant stress on EV batteries. If a battery is consistently exposed to high heat, either from the environment or from intensive use (like fast charging), it can lead to faster degradation. Thermal management systems in EVs help regulate temperature, but extreme conditions can still be harmful.
3. Electrolyte Degradation: The electrolyte in a lithium-ion battery facilitates the flow of ions between the anode and cathode. Over time, the electrolyte can break down, which impedes this ion flow, leading to reduced battery performance and eventual failure.
4. Dendrite Formation: During charging, small, needle-like structures called dendrites can form on the anode. These dendrites can grow large enough to pierce the separator between the anode and cathode, causing internal short circuits, which can lead to battery failure or, in extreme cases, fires.
5. Manufacturing Defects: Defects introduced during the manufacturing process, such as impurities in the materials or errors in the assembly, can lead to early failure of the battery. Even a small defect can result in uneven aging or unexpected malfunctions.
6. Overcharging or Overdischarging: Overcharging (charging beyond the battery’s designed capacity) or overdischarging (draining the battery completely) can cause permanent damage. Modern EVs have built-in systems to prevent these scenarios, but if these systems fail or are bypassed, it can lead to battery failure.
7. Physical Damage: External impacts, such as collisions or exposure to water, can physically damage the battery cells or the protective casing. This damage can compromise the battery’s integrity, leading to leaks, short circuits, or complete failure.
8. Calendar Ageing: Even if an EV battery is not used frequently, it will still degrade over time. This "calendar ageing" occurs as chemical reactions within the battery continue slowly, even when the battery is not in use.
9. Cell Imbalance: An EV battery pack consists of many individual cells. If these cells become imbalanced (where some cells degrade faster than others), the overall performance of the battery pack can suffer. Battery management systems are designed to keep cells balanced, but imbalances can still occur, leading to reduced capacity and efficiency.

Understanding these causes can help EV owners take steps to extend their battery's lifespan, such as avoiding extreme temperatures, not frequently fast charging, and not fully charging or discharging the battery.

Battery State of Health (SoH) is a metric that indicates the overall condition and performance of a battery compared to when it was new. It is expressed as a percentage, with 100% representing the battery's original, fully-functional state. As a battery ages and undergoes charge and discharge cycles, its capacity and performance naturally decline, leading to a lower SoH.

Key factors affecting SoH include:

1. Capacity Loss: Over time, the battery loses its ability to hold the same amount of charge it could when new. For example, a battery with an 80% SoH can only store 80% of the energy it could when it was first manufactured.
2. Internal Resistance: As the battery ages, its internal resistance increases, which can lead to reduced efficiency and higher heat generation during charging and discharging.
3. Cycle Count: The number of charge and discharge cycles a battery has undergone is a major factor in determining its SoH. Each cycle causes wear and tear, gradually degrading the battery's components.
4. Environmental Factors: High temperatures, frequent fast charging, and deep discharges can accelerate the aging process, reducing the SoH more quickly.

Monitoring the SoH is important because it helps users understand how much life is left in their battery and when it might be time to replace or take measures to extend its life. For electric vehicles (EVs), a lower SoH can mean reduced driving range and efficiency, making it an essential aspect of vehicle maintenance and performance management.

Yes. Much like the battery in your smartphone loses capacity over time, so too, your EV battery will lose capacity and range. Even if you did not use the battery, a process called calendar ageing will reduce battery capacity through slow chemical reactions within the battery.

But we should point out that most EV batteries are in still in cars. These batteries are designed and tested to very stringent specifications so that they last the life of the vehicle. So while we may read about EV batteries failing, the vast majority are doing just fine and there's no data today to suggest that EV batteries have a higher failure rate than other powertrain parts like engines or transmissions.

Use this text to answer questions in as much detail as possible for your customers.

No, our HealthCheck is a quick in-vehicle test. It takes about 3 minutest to collect the data and for our advanced algorithms to crunch the numbers and give you a battery health score. Don't let the speed fool you; it is a very comprehensive test that has been independently assessed and validated by CARA - Car Remarketing Association Europe.

New models are launched all the time, so we're continually updating our HealthCheck to include these EVs. Luckily, you won't need to check the battery condition of a brand new EV, so odds are we have a test ready and available well before you need it. Visit our book a test page to look up your vehicle.