And your insightful input with 33 years auto "exp"?
It's a fair question. I put 33 years of mechanical "experience" in my signature instead of "mechanic" because nobody pays me to do it anymore. I'm an IT program manager, and although I have worked professionally on VW's, Volvo's and Mazda's years ago, I'm more of a really good shade tree mechanic now. Since I was 18 I've spent most weekends fixing a project car, or a friends car. Engine rebuilds, transmission rebuilds & fixes, carbs & fuel injection, suspensions, electrical, body & paint. All bone stock mind you, never really go-fast stuff, mostly un-do what the last fool did, or just resurrect an old car from where the last owner just gave up. I stopped making my living as a mechanic because I liked to work more slowly and carefully than my bosses wanted to run their shop, which is fine. Anyway, so I think I know significantly more than the average enthusiast about making internal combustion vehicles go, but I'm admittedly an EV newb, which is exciting, something new to learn.
So I will say that I take a more broad brush approach to automotive charging systems than the group here does from what I've seen. Partly that's because of my experience is with traditional battery / alternator systems that you could fix with an ohm meter and a load test. ICE charging systems are just not that complicated. The situation the groups is dealing with here is decidedly more nuanced.
Here's what I think I know and some of what I think we should do:
0) I don't pretend to know everything there is to know about this problem. Somebody might, but I haven't talked to them yet.
1) Any 12v car battery that shows a voltage of 12.6v at 'rest' is charged. That's just math.
2) Any value above that (13.0v - 14.4) represents a battery that is charging or has just finished doing do, cooling down, what have you. On an ICE car, I would stop looking here and go find something cold to drink, watch Alaska State Troopers, fuss about my tires, whatever.
3) Battery sulfation is a function of age (hundreds of charge cycles) OR insufficient charging after discharge. When freshly discharged, a healthy 4 - 6 amp charging cycle will 'blow off' battery sulfation, sometimes you can even see the Pb crystals floating in the electrolyte before they are absorbed. On an ICE car, if I couldnt' get a battery to draw about 6 amps on a charger, and the battery was more than 3 years old, I would stop here and throw the thing in my trunk and buy a new one. Yes, I've been able to resurrect old, sulfated batteries before but it never really turned out to be as good as just getting a new one.
4) 90% of the time on an ICE car, your battery charging problem is/was a bad ground somewhere at the body / head / engine block / starter. It's magic how if you took a brass brush to all of those places, cleaned off all the crud, everything would start to work, charged battery, brighter lights, etc. I'm not saying that's what's happenening here, but because we don't have an alternator to fiddle with, but it's worth a look. Volvo's are particularly susceptible to crusty grounds, I don't know about Nissans.
5) We ought admit that this charging system is 'just different' than any ICE car we've ever owned. We can't touch the alternator and are thus vexed. If there was an alternator available when the car was at rest that we could stick an ohm meter on, we wouldn't be having this discussion I think, and everyone would be happier and drinking something cold, and watching Alaska State Troopers.
6) The group is spending a lot of time arguing & being personally hurt / insulted about battery chemistry, I don't think this is particularly useful. I think it'd probably be better to:
a) Get / Make / Steal whatever tool the dealer uses to test a Leaf charging system, if their is such a thing that isn't just an ohm meter and load tester.
b) Read the LEAF 12v charging system manual cover to cover.
c) Empirically test hundreds of charging systems / batteries as a group in a central location / database, gather TONS of facts and data.
d) Compare notes and discuss rationally.
7) Admit we may not arrive a common solution, and that's okay. Each of us has a different battery (brand, age, quality, level of abuse, ambient temperature environment, etc.). There's just too many variables in my opinion. Fuel injection is fairly finite if your injectors are clean. Bosch Motronic EFI used in tons of European makes will quite literally tell you precisely whats wrong with it if you listen, and if you can follow directions, any monkey can fix it. Charging systems are decidedly not this way because they involve a chemical reaction which confuses people and is why people needlessly throw alternators and batteries at cars when most of the time the problem lies elsewhere.
8) Our group seems to have a certain fury / rage about all of this that I think is misplaced. I get it that batteries are expensive (like 2x what they cost 10 years ago) and that this is marginally a safety issue and certainly annoying. But it's a battery. My dime is use the warranty, and then buy good enough batteries that you can keep using the warranty if you need to, because the charging system is effectively (AFAIK) what it is. If enough people report the problem to Nissan, something will probably change, presumably in the charging system firmware.
9) This is not personal. Full Stop.