There's now some independent analysis that says the Nissan Leaf wilts in the heat.
Led by Leaf owner Tony Williams, a group of Nissan EV owners tested a dozen Leafs in Phoenix last weekend. The group put the Leafs on a pre-planned route at pre-determined speeds to measure their fully charged ranges and to find out if extensive heat has led to premature degradation of the car's battery capacity, according to posts on the My Nissan Leaf forums and Green Car Reports.
The group found that half the Leafs tested had, at "full" charge, battery-capacity indicators showing just 10 out of the original 12 bars and averaged slightly less than the 73-mile single-charge range certified by the EPA. One Leaf had just eight bars showing – indicating about a third of the battery capacity was gone – and went just 59 miles before petering out. And one Leaf, purchased new only a month ago, was already missing a battery-capacity bar.