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Future Mobility & Trust

Ensuring vehicles remain safe, reliable, and trusted throughout their entire lifecycle.

EV Battery Health: The Foundation of Trust

State of Health (SoH): Why Battery Transparency Defines the Used EV Market

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
Trust in new technology is never given, it is earned through transparency. For electromobility to reach its full potential, the condition of a battery must be verifiable by anyone who depends on it: the dealer pricing a trade-in, the fleet manager assessing residual value, the private buyer making a long-term decision. Manufacturer-independent testing procedures are the foundation that makes this possible.

Why Independent Battery Validation Matters for the EV Market

New technology only scales when people trust it. In the transition to electric mobility, that trust has a very specific bottleneck: the battery. It determines range, resale value, insurance risk, and long-term usability – yet for most buyers and dealers, its actual condition remains a black box. Independent, third-party validation is what opens that box. Across the vehicle lifecycle (from new car homologation to used car trade-in to end-of-life assessment) objective battery diagnostics create the transparency that secondary markets, fleet operators, and consumers need to make informed decisions. As the EV market matures, the ability to verify battery health independently will become as standard as any other vehicle inspection.

How DEKRA Supports Battery Transparency Across the Lifecycle

Addressing battery uncertainty requires expertise at every stage, from a vehicle's first homologation test to its transition into the secondary market and ultimately to end-of-life assessment. DEKRA operates across this entire lifecycle, providing the independent validation that manufacturers, fleet operators, dealers, and regulators depend on.
  • Sustainable Batteries: From eco-design and life-cycle assessment to recycling, supporting a circular approach to battery systems
  • Batteries in EVs: State of Health evaluation, high-voltage safety, and condition reporting for used vehicles, the technical foundation for a transparent secondary market
  • Battery Compliance & Training Services: Navigating regulatory complexity, including the EU Battery Regulation, and training for the safe handling of high-voltage technologies
  • Testing & Certification of Batteries: Laboratory testing and certification against international safety and performance standards, from component level to full system

The Infrastructure Behind Independent Validation

Independent validation is only as credible as the infrastructure behind it. DEKRA's specialized Battery Test Center at the Lausitzring (Brandenburg, Germany) and Automotive Test Center of Excellence in Michigan (USA), both commissioned in 2025, provide the technical foundation for battery assessments across the full lifecycle (from homologation testing to used vehicle diagnostics) at a global scale.

FAQs: Understanding EV Battery Health and Testing

Used EV sales are growing rapidly, but the battery condition remains the single biggest barrier to buyer confidence. Without reliable data on remaining capacity, buyers discount heavily or walk away, depressing residual values for dealers, leasing companies, and private sellers alike. Independent State of Health assessments address this directly: they provide a verifiable, manufacturer-neutral picture of battery capacity, enabling fair pricing and reducing the information gap that currently holds the secondary market back. As the used EV market matures, battery health transparency is becoming as expected as any other vehicle inspection result.
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 binding requirements across the entire battery lifecycle – from carbon footprint declarations and minimum performance standards to the mandatory Digital Battery Passport by 2027. For EV testing, this means expanding beyond traditional safety and performance metrics to include lifecycle data, material traceability, and ongoing performance documentation. The regulation effectively raises the floor for what "tested" means: compliance now requires structured, verifiable data across the battery's full history, not just a snapshot at point of sale. For manufacturers, fleet operators, and importers, understanding these requirements early is essential to avoid market access barriers when the obligations become enforceable.
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