OK, this is what Solar Assist recommended for my system, and which I purchased:
1 X Device with software:
https://solar-assistant.io/shop/products/device_rpi5
1 X Inverter USB cable:
https://solar-assistant.io/shop/products/sunsynk_rs485
1 X RJ45 splitter:
https://solar-assistant.io/shop/products/deye_rj45_split
SunDave is right. You cannot monitor batteries themselves and the inverter at the same time. If you monitor the inverter, you get basic battery info. You can switch back and forth between both though. For more information on batteries, they provided this link:
https://solar-assistant.io/help/battery/eg4
There is a video at the bottom.
I bought 2 of these: RJ45 Ethernet Splitter Cable, RJ45 1 Male to 4 x Female Head to Head LANE Splitter Adapter Cable Compatible with Cat5, Cat5e, Cat6, Cat7 Network Cables
And 6 of these: [High-Speed Converter] High-Speed USB to RS-485 Converter Module | Plug & Play, 600bps to 115.2KB/s
Will see how that goes, but it will be a while before I get to it with time to install and vaca.
If you want a more private phone, you shouldn't just roll over.
Buy an UNLOCKED pixel phone, then go here on it:
https://grapheneos.org/
-Download, install, and follow instructions.
-Don't do this if you are not at least a little tech savvy or have a tech savvy friend, but it is pretty easy now. You need an UNLOCKED phone AND a HIGH quality (thick) USB C cable, or it won't work. Don't do this with a phone not recommended for GrapheneOS.
-If it isn't installed by default, install F-Droid to get apps that respect your privacy. But, you'll need more apps, so download Aurora Store and install that.
-Get the NetGuard App. Gives you granular control of what leaves your phone from what app and when.
-Magic Earth works ok for directions. You'll have to download the maps to your phone, which takes a bit of memory and download time. You can still use google maps from the browser, but yea...
-Simple Apps work for calendar and contacts. FairEmail works pretty good for emails.
-Brave Browser is probably one of the most private browsers, but the default Vanadium is pretty good too.
FREE of iPhone and Google restrictions and herding.
For God's sake, stop using the stupid WhatsApp and Messenger apps. If you think those provide you ANY privacy, you can probably hear me laughing from here. Same for the new iPhone.
You won't be able to do banking with this setup. The banks want more access to your phone than GrapheneOS will allow by default. If you want do to that or use google maps, or other google apps, you can try sandboxing the google app store and apps, which blocks google from areas of your phone from which you restrict them.
Each step from F-Droid to Aurora to sandbox you lose some privacy. And you will NEVER have complete privacy. But, you will cut out most of the crap and secure your phone from more malware. I don't do many apps, just essentials. And, because I don't do banking on my phone, if my phone gets stolen, oh well. Get another $300 used unlocked pixel and restore my setup to it.
I'd recommend ditching Windows and Mac as your primary machine too and move to Linux without systemD (ie MX Linux and others), but that's another rant.