Some of the early models - either the Chevvy or Nissan Leaf - had battery packs which would degrade very quickly. This was causes by the charging system which seemed designed to destroy them.

The expectation in the EV fan world was that modern (> 2019) battery packs were very likely to retain 80% of their charge for well over the time anyone expected with the drop to 80% itself taking most of the car's expected lifetime. This was because the standard extrapolations ignored improvements in charging algorithms and that real-world usages were expected to be better for the battery than the models.

Another prediction we made is that range under cold (or very hot) weather would be significantly reduced and that seems to be the case too.