FireEngine: Did you look at the graphs in the report? In a couple of years (ie around the 4yr mark), the 30kwh is likely to decay to some 40% SoH - half of what Nissan predict at the 5yr point. Thats not going to be fixed by a fine-tuning of the indicator IMHO.
Yeah, I did, and I noted that they didn't relate decay or SoH to KM's, or the rate of being driven (unless I missed a graph?). A few things about the report that struck me were that it was primarily NZ based and therefore is (naturally) on imported vehicles, which it self will causes bias through selection. If you are using the graphs to extrapolate future decay, the way we import and use the cars will artificially stack the results in favour of older cars.
I am interested if a Leaf dealer can confirm or deny the follow theory:
1) We generally don't bother importing cars with poor battery SOH, so all the older 24 Kw's in NZ are the cream of the crop with better than average batteries, where as the 30kws are so new, not enough time has lapsed pre-import to sort the good from the bad and so both good and bad 30kw's have been imported. The batteries can contain latent conditions that affect their future decline such as variations in manufacture, through to how the previous owner drove and charged them, and weather they came from the milder south of Japan or harsher north of Japan, and weather they were parked out doors or protected in a garage.
2) I reckon kiwis use these cars heaps more and heaps harder than the Japanese - we typically import low KM examples and then rapidly pile on the Kms. This (if true) will produce skewed statistics when graphing SoH vs years. Due to averaging out the results, a recently imported 2013 model with lows Kms and good SoH will look a lot better on those graphs than a 2016 30kw with low kms and good SoH even if 10,000kms of use is producing identical decline of SoH in both cars.
I don't think I'm barking up the wrong tree. Can you see a flaw in my logic?
Nissan's expectation of the Leaf is 80% SoH at 5yrs. That looks in line with the 2.4kwh but well adrift on the 30kwh. Unless someone is going to tell me the battery is physically 20% larger in the 30kwh model then the increased capacity <has> to come from a different battery technology with a significantly higher energy density. Simple logic and Occam's razor links the two, no complex usage effects required. I'd also suggest there looks to be enough variation in the 24kwh battery SoH in the data that would contra-indicate a "cream of the crop" selection taking place on the 24kwh models.
Users are also reporting real range reductions in line with the reduced reported SoH by the vehicles so in Apollo 13 terminology "its not instrumentation".