I just pulled the plug after doing all the research and decided to simplify things by skipping Li batteries for now. My config might not be the bee’s knees system, but it surely made it a much more manageable upgrade. I didn’t need to touch my existing converter and my existing FLA batteries still have plenty of life- and the most “green” option is to use up their useful life!
I ended up getting an upgraded MPPT and I’m designing my cabling and placement of all the new solar equipment with the eventual switchover to Li batteries in mind, once my FLA wear out. The biggest change for my rig is placement, as that the Li need to be inside rather than in the under stairs (but exposed) area the FLA currently are. This means my solar controller will be a little further from the FLA than recommended, but I already have some beefy cabling connecting the two locations.
I got a cheap Chinese shunt and device to measure FLA SOC for peanuts. When I switch to Li in a couple years, the BMS are already coming with Bluetooth and ability to check SOC directly on the battery- so that should all be pretty standard and cheaper in the future.
The decision to leave out Li for now meant it was so straightforward:
-Panels and mounts
-Mppt controller (with Li charging profile for future)
-Cabling to hook it into existing circuit
-Resettable fuse between panels & PV controller (protects circuit and gives me a “shutoff” for the panels)
-Fuse between PV controller and battery+
-shunt and SOC meter @ battery -
Everything else is existing, including my WFCO converter, and no need to add DC-DC.
If you do go Li, you need all the above, plus swap out your converter for one with a Li profile (or at least a programmable one), and as mentioned a dc-to-dc to prevent the Li from pulling too much current and possibly burning out your alternator. [some folks swear you don’t need one. If your batteries are always >80% SOC when driving, IMO, they are probably right, otherwise it’s cheap insurance.] Instead of a separate Dc-to-dc and MPPT, you can get a single device to do both those- like https://www.renogy.com/dcc50s-12v-50...ger-with-mppt/
Even with that, you’ll still need a new converter to handle the Li on a/c (gen or shore) power.