Changing over to Lithium Effectively

[swamp]

Every time I think I have a handle on this I end up with more questions. Our sealed lead batteries are shot so I would like to find an efficient way to move into the Lithium battery field. We currently 400W of Renogy 12v panels into a Renogy Commander 30A Controller with MT50 interface along with 400Ah lead batteries, and a 300W pure sine inverter. The controller is the older version that does not have LIFePo4 setting. I understand that there is a way to program the MT50 to allow the use of Li batteries, but I want to make sure before I spend that kind of money and risk damaging the new batteries
We don't use a lot of power at camp, but I would like to put the water well pump on the system and we do run a stand fan at night along with a couple of hours of 30W12V LED in the evenings. I would prefer to stay at the 12V system for now and just get batteries with the low temp charge cut off, but if I have to change out my controller I want to be sure I get one that will suit my needs when I expand my system to include the well pump. I looked into the Grow Watt Soniker with the 24V and split phase inverter, but it's 24V complicates things again and it says it's for Lithium Ion and doesn't specifically mention LiFePo4 settings. Is there a way to ease into the LiFePo4 batteries without changing the entire system right away?

 

[Samsonite801]

Here's a good prerequisite video to check out as you inch into LiFePO4 (to help you decide on your charge/discharge voltages):

 

[Samsonite801]

Reference chart:

 

[DThames]

I have 2 Growatt 3000 units in split phase setup. They work fine with LiFePo4. I forget the name of the battery mode but it is the Lithium without BMS as I recall. The Lithium with BMS is for Growatt supplied battery and their own BMS communication connection. I am not familiar with "Grow Watt Soniker".