question

I should have the MPPT and 1.5KW of panels ready to go later today, so before I discharge Battery 4, I think I'll just see what happens with the MPPT charging in DVCC and the batteries (perhaps) balancing themselves and such. Maybe this will sort itself out.

I haven't put any loads on the batteries, so the only load will be the MPPT itself when I finally flip it on.

@AlaskanNoob

TLDR leave them charged connected to each other so they can balance as individuals and as a pack.

The Pylontecs sort themselves out. You can have a whole stack at different state of charge.

They do need a good charge when new (this can be done altogether) and be left at 99/100% for a few days to get things balanced on the initial charge particularly.

You can get a higher pack voltage than soc if some cells are higher than others (so not fully charged but refusing charge for balancing purposes)

Maybe charge them up a bit slower as well.

Powered up the Cerbo and got this info.

And after cracking one of my trackers in my MPPT RS using the 2.4Nm torque setting in the printed OLD manual (which has been removed in the NEW manual), I wired up our 3 solar panels into a different tracker.

And powered it all up for a first attempt in the rain and fog...

Amazingly enough, no sparks, no smoke, no errors and even with only 3 panels temporarily set up, we are getting a little something and batteries seem to be charging. Most we've seen in the hour or so of charging is 450W or so, but not bad for late in the evening on a foggy rainy day. That's more power than we've ever made with our little Renogy Panels and Goal Zero on even the sunniest blue sky day.

DVCC is on and everything looks fine to me perusing the settings.

Good to see your progress above although I am gutted for you at the cracked tracker connection. 2.4NM is a pretty common torque settings here in the UK for the larger connections inside a typical consumer unit along with 2NM on neutral and earth bus bars and 1.2NM on RCBO terminals. I also have a torque screwdriver which I use for everything these days and would be really annoyed if something broke while using it. I think the AC connections inside the Multiplus-II are something like 1.6NM off the top of my head but I always refer back to the manual any time I torque them up. I really should print little labels to put next to the terminals as should have been done at the factory IMHO.

As for your cell balance, it already looks pretty good already.

I can't speak authoritatively about grounding as it varies by regional wiring codes and of course you are off grid which I'm not. In my case I have a MET (main earth terminal) as part of my AC feed from my power company and this has been supplemented as required by the UK wiring code for use in island mode (essentially off grid when grid power has failed). So all my AC earths come back to this earth point along with the earth terminals from my Pylontech batteries. I have not earthed my MPPTs or my PV array as there are different opinions on what to do in that area. I am in a very low risk area for lightning so don't feel the need for DC surge protection or array earthing. If I did earth my array then I would need a completely separate earth rod for this purpose and that's actually very hard to do on a metal structure and metal skinned garage where the panels are mounted. I do have AC surge protection because my AC feed is from overhead 11kV lines with a dedicated transformer on a pole outside our house. This is at greater risk of being hit directly or indirectly by lightning and so AC surge protection is important. No point in frying my inverter just as the grid fails...

We've actually had 3 or 4 grid failures in the last year and have barely noticed. We only actually notice when we realise that our range cooker isn't working or our EV charger isn't working because those loads are not maintained in island mode. But apart from that life goes on as normal until the batteries die, and since the batteries are DC coupled to the solar array, in daytime we can keep going from solar power + battery. It's really a great system.

Good luck with your next steps.