SOH Insight: Battery Health Reports

SOH Insight generates state-of-health reports for EV traction batteries. This is the most critical due-diligence step when purchasing a used EV — especially from Japan, where battery health data is not standardized in auction sheets.

What SOH means

State of Health (SOH) is the ratio of current battery capacity to original rated capacity, expressed as a percentage. A new Nissan Leaf has 100% SOH. After 80,000km of mixed charging, a typical Leaf might show 78-85% SOH depending on climate and charging patterns.

SOH below 70% is generally considered degraded for a primary vehicle. SOH below 60% substantially limits usable range and reduces resale value.

How WATTSHIP generates SOH reports

SOH Insight processes available diagnostic data alongside auction sheet grade information and fleet history patterns to produce an estimated SOH range with confidence intervals. The report covers: estimated current capacity (kWh), estimated range at 80% charge, degradation trend projection, and risk rating.

Quota limits by tier

Reports reset on the 1st of each month. Unused reports do not carry over.

Reading your SOH report

The report shows an estimated SOH range (e.g., 82-89%) rather than a single number. This range reflects the confidence interval given available data. A narrower range indicates higher-quality input data.

Green: SOH above 80%. Suitable for primary vehicle use. Amber: SOH 70-80%. Suitable with range expectations adjusted. Red: SOH below 70%. Significant degradation — factor replacement costs into purchase price.

Limitations

SOH Insight provides estimated ranges based on available data, not a physical plug-in measurement. For high-value purchases, a pre-purchase physical inspection with OBD-II diagnostic equipment at the source location provides definitive battery health data. WATTSHIP can connect you with inspection services in Japan for vehicles priced above your cross-border cap.