Professor John Kelly of Weber State University, who has a number of great videos involving the assembly/disassembly of Chevy Bolt and Volt batteries, among others, has a new video out in which he takes the Nissan LEAF battery temperature management to task. Unfortunately, he bases his criticism on language in the owner's manual about the care of the lithium ion battery. However, the text he quotes is the typically cautious sort of statement that manufacturers often use, and it comes after the statement: "To maximize the battery's useful life, use the following driving and charging habits where possible" He then goes on to note that Bolt and Volt manuals don't have language that is as similarly cautious. I have to say, I'm a little disappointed in in the prof. Maybe there is a case to be made that the Nissan battery temperature management is not as effective as those in the Chevy LEAF or Bolt, but quoting language in an owner's manual is no way to make it. Give me data. Show me how it affects battery degradation with numbers, repeatable tests. Certainly the Nissan approach to the LEAF battery temperature management was absolutely a problem for early LEAFs, and some say it is still a problem. But, if you're going to make a claim like this, especially on an official channel of an institution of learning, give me data. Show me by how much more (or less) degradation occurs over time and usage in certain temperatures. Here's the video, so you can judge for yourselves.
While I'm similarly concerned about the new Leaf, I agree with you that jumping to conclusions based on the manual isn't adequate. It immediately reminded me of this absolutely hilarious hit piece before the Bolt release on Electrek: https://electrek.co/2016/12/07/gm-chevy-bolt-ev-battery-degradation-up-to-40-warranty/
https://insideevs.com/nissan-leaf-30-kwh-battery-degrading-more-rapidly-than-24-kwh-pack/#comments Well that doesn't bode well for the 40 kWh battery. I still highly recommend people wait for the LG supplied pack Leaf. Especially here in Texas where summers can get really hot and humid. LG has had a great track record with GM at least. Hopefully that continues with Nissan.