My understanding now (after several man hours spent researching the net on the topic) is that AC charging to 100% is fine even on a NMC batteries as long as it’s done via AC charging, and the car is used soon after. Not ideal generally, and even more so on NMC, but it’s ok.
As for how frequent this should be vs can be: it should be at least once a month to balance the pack, can be as often as you like because ultimately the pack will outlive the car and if you need the range you should well take advantage of it. The more often you do the more balanced the pack and more accurate the range reading, but yes degradation (state of health / internal resistance) also becomes more noticeable over the life of the pack, much more on NMC than LFP.
And even more importantly it is to understand whether you are cycling the battery from low to high voltage or only recharging partially within the middle of charge (say 50 to 75)
So how do I interpret this on a daily basis?
I would treat both NMC and LFP batteries the same given my usage pattern which sees short journeys daily half of the month, and longer journeys once a week the other half of the month.
Neither pack likes being cycled from low to 100: LFP tolerates it much better, but for practical purposes, NMC does just fine.
I don’t want people to stop buying electric cars because of range anxiety and worries such as how much and how often to charge, therefore I would say: do what you like, just don’t complain if 10 years later the pack is ready for the bin.
