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Understanding battery health (SoH)

State of Health (SoH) is the battery’s remaining capacity versus when new (e.g. 92% after a few years). For a used purchase it’s the single most important number — it drives both range and resale value.

Good news. Modern batteries last better than feared: an analysis of ~24,000 certificates (Arval) found that after 6 years or 160,000 km they retain, on average, over 90% of capacity.

Get an independent test. Don’t rely on the manufacturer’s readout alone — an independent check builds trust:

• Aviloo — a quick FLASH test via the OBD port, or PREMIUM over a full charge/discharge cycle.
• DEKRA — a capacity test in ~15 minutes (method validated by RWTH Aachen).
• TÜV SÜD — battery certificates.

EU Battery Passport. From 18 February 2027, EV batteries (> 2 kWh) must carry a digital battery passport — standardised SoH and range data via a QR code. Evident’s data model is built to ingest it.

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