Source: https://insideevs.com/news/331004/exclusive-interview-with-steve-marsh-as-his-nissan-leaf-hits-150000-miles-original-battery/
"Reliability – very good, if not excellent. That being said, There is no more regeneration – going down a hill in ecomode is like being in neutral. From a start, it accelerates like there is a parachute hanging out the back while in ecomode but nothing goes back into the battery.
The only other issue I have had is that the brakes grab and release when applied lightly while the battery is in LB or VLB. I attributed this to trying to regenerate but no place for the energy to go. I haven’t taken it in to be looked at because it is only very apparent during specific circumstances that are repeatable." - Steve Marsh
Battery still works but holds 7 out of 12 battery capacity bars (below 60% of capacity) and is rated at 147 GIDS - so more precisely 52% of the original capacity remains.
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Here are some more examples of Nissan Leaf running high mileage.