03 Apr 2024Automotive / E-Mobility / Safety on the road
Used Electric Cars – What about Battery Health?
Are used electric cars really a risk for users? More disclosure on drive battery condition helps to eliminate doubts.
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EV Battery Testing: Building Trust in Electric Mobility
Electric vehicles are reshaping the automotive market, but a fundamental challenge has emerged: in the growing used EV market, the battery is the single largest cost factor, yet its actual condition remains invisible to buyers and dealers alike. This uncertainty drives residual values down and keeps demand subdued. The State of Health (SoH)
– a battery's remaining capacity relative to its original state – is not just a technical figure. It is the central question every used EV transaction depends on. When buyers can trust the answer, markets function. When they cannot, hesitation wins.
Independent, manufacturer-neutral SoH assessments are increasingly becoming the mechanism that turns uncertainty into informed decisions – for buyers, dealers, fleet operators, and insurers alike.
The focus of vehicle inspection is shifting. As emissions checks become less relevant, the real challenge lies in ensuring the safety of high-voltage systems, powerful batteries, and increasingly automated driving functions. Future mobility will depend not only on technological innovation but also on trusted and independent validation throughout the entire vehicle lifecycle.
Stan Zurkiewicz, CEO DEKRA
To secure this trust in the new technology over the long term, reliable, manufacturer-independent testing procedures are essential. Only when fleet operators, dealers, and end customers can rely on the actual condition of the battery will electromobility gain long-term acceptance and reach its full potential.
Importance of Reliable Battery Testing: Empowering the Transition to Sustainable Transportation
Innovations require safety to scale successfully in the market. As a global partner in the transition to electromobility, DEKRA guides manufacturers, fleet managers, and end consumers through the complexity of this transformation. Independent validations and certifications are key to ensuring the safety, performance, and longevity of EVs throughout their entire life cycle. As acceptance of electromobility grows, trusted battery diagnostics and transparent State of Health assessments will become increasingly important to support values, secondary markets, and long-term consumer/customer confidence. Through objective testing standards and our decades of expertise in vehicle inspections, we create the necessary credibility. In this way, we enable progress that is not only technologically groundbreaking but also safe and responsible.
Read More About E-Mobility
Our Battery Services: From Sustainability to State of Health Validation
Today, the requirements for battery systems are as diverse as their applications. Instead of isolated individual services, DEKRA offers a holistic portfolio that covers the entire life cycle and all regulatory aspects. To provide the necessary safety and compliance, we bundle our expertise into four core areas:
- Sustainable Batteries: Solutions for a sustainable circular economy – from eco-design and life-cycle assessment to recycling.
- Batteries in EVs: Focus on safe operation, including precise State of Health (SoH) evaluations, high-voltage safety, and well-founded condition reports for used vehicles.
- Battery Compliance & Training Services: Strategic guidance through complex regulations (such as the EU Battery Regulation) as well as specialised training for the safe handling of high-voltage technologies.
- Testing & Certification of Batteries: Comprehensive laboratory testing and certifications to ensure that batteries meet the highest international safety and performance standards.
The Technological Backbone of Battery Testing
Our world-leading testing facilities, including the specialised Battery Test Center at the Lausitzring (Brandenburg, Germany) and our Automotive Test Center of Excellence in Michigan (USA), were commissioned in 2025 and serve as the technological backbone for these comprehensive validations worldwide.
As the adoption of electric vehicles increases, the used EV market is growing rapidly. However, uncertainty regarding battery condition remains one of the biggest barriers for buyers and sellers. Independent third-party State of Health (SoH) assessments help create transparency regarding remaining battery capacity, support fair pricing, and strengthen confidence in used electric vehicles. This makes battery diagnostics increasingly important for dealers, fleet operators, insurers, and consumers alike.
The 80-20 rule is a widely recommended charging practice for EV owners: charge to a maximum of 80% and plug in before dropping below 20%. Keeping the battery within this range reduces mechanical and thermal stress on the lithium-ion cells, significantly slowing natural degradation over time. The practical consequence for the secondary market is direct: a vehicle consistently charged within this range will show a higher State of Health (SoH) percentage when independently assessed, which translates into stronger residual value and greater buyer confidence at the point of resale.
SoH measures a battery's current capacity relative to its original state when new. As a general benchmark: above 80% is considered excellent for a used EV; between 70% and 80% is typical for older vehicles and still delivers fully functional range. Most manufacturers guarantee a minimum SoH of 70% for the first eight years or 160,000 kilometres. What matters beyond the number itself is how it was measured: SoH values derived from manufacturer software can vary significantly between brands, as there is currently no standardised cross-manufacturer calculation method. Independent third-party assessments apply consistent methodologies, making results genuinely comparable, which is increasingly what buyers, dealers, and fleet managers require.
Battery testing methods are tailored to the specific stage of the vehicle's life cycle:
- Diagnostic SoH Evaluations: Primarily used by dealerships, fleet operators, and during vehicle inspections. This software-based method reads data from the Battery Management System (BMS) to determine residual capacity for the used car market.
- Laboratory & Homologation Testing: Conducted for manufacturers before a vehicle enters the market. It includes rigorous electrical, thermal, and physical stress tests to ensure compliance with international safety standards.
- End-of-Life Assessments: Used when an EV battery is retired. These tests determine whether a battery is suitable for second-life applications (such as stationary energy storage) or if it must proceed to sustainable recycling.
Together, these methods form a comprehensive framework for independent battery assessment, giving every stakeholder along the vehicle lifecycle a reliable, verifiable basis for decisions.
The EU Battery Regulation introduces strict requirements to make batteries safer, more sustainable, and circular throughout their entire life cycle. It mandates comprehensive carbon footprint declarations, strict minimum performance standards, and the implementation of the Digital Battery Passport by 2027. Consequently, EV battery testing must now expand beyond traditional safety and performance metrics to include detailed life-cycle assessments and data verification. DEKRA’s specialized compliance services guide manufacturers and fleet operators through these complex regulatory changes to ensure full market compliance.