johnlocke said:
We have at least one owner with 2700 charge cycles and 12 bars. We have a multitude of others who failed before they reached 60,000 miles and got a warranty replacement. we also have a lot of owners with over 60,000 miles on the original battery who didn't qualify for a warranty replacement. Some have nearly full capacity while others are down to 6-7 bars. The 30 KWH battery is warrantied for 100,000 miles or 8 years. We are starting to see failures on the 30 KWH batteries but the bulk of the failures are going to occur in the future( over the next 5 years). Nissan has said that they expected the battery to retain 80% of it's capacity at 100,000 miles. Therefore their expectation was for at least 2000 cycles before the battery met replacement criteria. I don't think a 1500 cycle lifespan is unreasonable. Nissan knew that their battery was subject to thermal cycling and I'm sure that was taken into account by Nissan.
Of course the research is conducted at steady temperatures. How else would you do it? But it is also done over different temperatures and research does show that batteries fail sooner at higher temperatures. That's why I gave a range of 1000-1500 cycles. The research is still applicable even if your battery isn't temperature controlled. In a cool climate i expect most 24 and 30 KWH batteries will exceed their warranties. It still ends up a throw-away car with little or no resale value because the batteries will be range limited after the warranty expires.
The 60 KWH battery will solve that problem on the new Leaf+. The Nisan battery won't hold up as well as a battery with TMS built-in but it will probably be good enough to last 200K mi. at least in COOLER climates.
IMO, your post captures at least some of the uncertainties surrounding matters, including the ~60 kWh battery where there may be insufficient empirical data as yet to get a sense of the rate at which it will lose its range in the hotter climate areas. When I considered this uncertainty, and that Nissan does still seem to be selling the vehicle in those climates (including Mexico?), it made me wonder whether a line of reasoning should be:
"Ok, so you think it's ok to sell this vehicle (with as-yet-unclear improvements in thermal management efficacity and related battery longevity, and as-yet unclear price on future battery replacement) to folks in these communities, even though some of those folks have to make a major life financial decision to purchase the vehicle and even though this means they're taking on a risk they may not fully appreciate as to how much the range of the vehicle will degrade, and even though (AFAIK) the competition does not have the same questions or limitations on DCFC use as in #rapidgate. I am not sure, but perhaps bringing back the concept of leasing batteries (perhaps even leasing new batteries in old chassis) would eliminate questions around range retention and vehicle value in those communities."
Nissan is going forward with the sale of not-very-well-cooled batteries (after so many years of being told by some drivers and dealers it was an issue in some areas), and to me this begs the question of how will this play out in the hotter climate communities. While it does seem possible that chemistry and pack architecture measures might pleasantly surprise us as ways in which the batteries are preserved, it also seems possible that they won't. This summer I was in a city in Mexico which, on one day a few years ago was technically, at that moment, the hottest city in the world. How will the battery life questions play out in that type of environment? If the batteries degrade a lot in some hot areas, and need to be replaced under warranty, then this is a significantly dissatisfying hassle for at least some of the drivers, and a big expense for Nissan, and also begs the question of how the battery replacements will perform (given that the cooling technology likely would not be changed).
Still, if the batteries do degrade sharply, whether within or outside of warranty, the longer range to begin with will take the sting out of it for at least some owners. If a driver all of a sudden can go only 140 miles on a charge, this might be ok for many, at least in the short run, though it will likely degrade the value of the vehicle faster than they wanted. I don't really have a strong idea of how that side of things will play out. Perhaps the longer-range-to-begin-with argument will end up trumping a lot of the issues here, and on balance sale of Leafs in hot climate areas won't be as problematic as all that, and maybe friends and associates will partly or mostly be satisfied with their Leafs around here.
One other thing - I am guessing at least some of the reason that Nissan has gone with this approach has been safety, and it's somewhat hard to argue with that.
