Thank you very much for the video! Being a nerd, I watched the whole hour-long discussion of undesirable parasitic reactions in electrolytes and loved it. I guess the conclusion it that high temps (as you say) and charging to high SOC (as we all know) is bad, and the time the battery spends in these bad conditions is more important than the number of charge-discharge cycles. He didn't say it explicitly, but it sounded like it's better to let the SOC run down over a few days driving and then recharge, than to keep the car topped up nightly, since that would keep average SOC lower over time, and perhaps battery temp lower over time. However, that seems to go against recommendations I have heard, and perhaps it would be bad for the life of the car's low-voltage battery. The broader conclusion is that battery chemistry is a black art, particularly as regards giving the cells a long useful life. For example, the 90 cells may have different electrolyte additives than the 85 cells, which may give the two different durabilities under various different conditions. There is no way for outsiders to know or even make an educated guess about most of the relevant questions unless the experts at the company who know the characteristics of their particular batteries disclose the answer.
Tesla is not obligated to update performance for P85DL beyond what has been advertised and measured so far (essentially 0.2 better in 0-60 and 0.2 better in 1/4 mile). It can either be from hardware differences between 90kWh and 85kWh battery or an artificial differentiation between P85DL and P90DL (to maintain a value gap).
