Recurrent Auto's EV Battery Health Study: Real Degradation Data Across Major Models

From a shop perspective: the early Leaf pattern the Recurrent data describes is exactly what we see. Any 2011–2017 Leaf that spent real time in a hot climate comes in with at least 1–2 capacity bars lost, sometimes more. We've started running a quick LeafSpy check during any Leaf service appointment to give owners a heads-up. If you're buying a used Leaf, make the seller run LeafSpy before you sign — five minutes, tells you exactly what you're getting.

The thermal architecture finding is what this data set uniquely proves at scale. We knew qualitatively that Leaf owners in hot climates saw worse degradation — now there's quantified median retention data: 72–76% at 5 years in California versus 85–88% in Minnesota for the same cohort. That's not a subtle difference. Air cooling is structurally inadequate for high-cycle residential EV use in warm climates and Recurrent's data shows it clearly.

The DCFC frequency finding is more nuanced than I expected. For liquid-cooled vehicles with active thermal management during charging (Tesla, Ioniq 5/6, BMW i4), no statistically significant correlation with accelerated degradation at realistic use rates. It's the Leaf specifically where every DCFC session is a thermal stress event without active cooling. The guidance differs by architecture, not blanket "avoid DC fast charging."

At $19–39, a Recurrent report before buying a used EV is the most obvious due diligence spend I know of. A 15% battery health difference in a used Model 3 is 30–45 miles of reduced highway range and potentially $3,000–5,000 in resale value. There's no other single document that captures that information for a specific VIN.