Most default settings are too high. About the only batteries that will tolerate them are battleborns - they're using different cells.
Hopefully, Im stating something that is already obvious to you, but you dont want to mix lithium batteries with AGM batteries. Its just that you yourself admit that you are new to lithium batteries and didnt say anything about "replacing" the AGM's with the lithium so it got me to worrying a little. If used right, you'll only want more of those lithium batteries. Good luck.
Just one other thing. I agree with Browneye that you shouldnt depend upon a control chargers default settings(or the default settings on any lithium charger) to charge your new lithium battery. Every major lithium battery manufacturer lists their own preferred charging parameters for their particular batteries. You can usually find these parameters in the paperwork that comes with a new lithium battery. If not there, look the parameters for your battery up online. Charging parameters for different makes of lithium batteries wont differ as much as they can for AGM's but I figure its always good to go with whatever the actual battery manufacturer recommends.
My first Lithium battery, I charged up with a charger designed for AGM's since my fancy, 60amp max lithium specific charger hadnt arrived yet and I was too excited to wait. My AGM charger has adjustable current output(up to 40amps) and charges to a voltage of around 14.3. Except for the fact that it wanted to shift into float mode at full charge, it actually worked fine to charge my lithium battery-even according to the manufacturer's recommendation. The battery arrived at about 40% to 50% charge-which is how they should arrive-and I slow charged at 10amps to full. Took nearly a day lol! But I wasnt in a hurry at that point and batteries last longer if you consistently charge them at slower rates.
I dont know anything about Chin's batteries either. I only assume that most LiPo batteries sold today have some level of BMS built in with cheaper batteries usually having no low temp protection. I recently purchased four Weize 200ah batteries which, for the cost are very well put together and have a BMS that shuts down charging in low temps. Almost immediately after I bought the Weize batteries, I found 200ah "Himassi" batteries on Amazon for $499 which is $150 cheaper than the Weizes. The Himassi's are supposed to use grade A prismatic cells, be heated AND have bluetooth monitoring. Of course I cant help but be suspicious of such a feature rich 200ah battery for just $499. Theyd be a steal if they're for real. On the other hand, Weize has been around awhile and hopefully will continue to be for another while. I figure this is important for several reasons, to include how many no-name Chinese battery manufacturers end up having lifespans shorter than the warranties they promise(Weize offers a 10yr warranty on their lithium batteries). Still! I sure am curious about those Himassi batteries. If I was a bit richer, Id buy one just to check it out.
PS; I know lifepo4 batteries can be charged at phenominal rates compared to variations of LA but slow charging is a habit developed from previous, long term AGM use and does no harm to the lithiums either way. Besides. Im talking just the initial, out of the box charge up. After that, they went into my system where the rate of charge, as Im sure that you definitely already know, is dictated by charge controllers.
I live full time in a 40 foot motor home in Northern Maine. Unlike your lithium battery situation, mine pretty much demands some type of cold weather protection! Its not as bad as you might think though. I keep the RV in a 44x16 garage during the winter. The garage isnt heated or insulated but does help a lot against the cold by preventing the wind from taking as much heat away from the RV. My 1st winter, I was sure that all the plumbing in the RV "basement" would freeze up so I installed several, low temp activated heaters there. Oddly, the basement never drops below 43 degrees even on the coldest days and none of my heaters have ever had to kick on. My lithium batteries live in that basement too. Apparently I dont have to worry about them getting too cold but still do.
How many panels do you have and what are their wattages? How do you have them configured(series, parallel, etc.?). Also, the same general questions for your current AGM battery bank. Im assuming that youre probably running everything parallel at 12v but Im told that I should never assume. I started out 12v everything-panels, battery bank, etc. Last summer, i converted my panel arrays to 24v but maintain my battery bank at 12v. That makes sense for me since most everything in an RV is 12v based anyway. When i switched to lithium batteries, i kept my AGMsas a back up bank by connecting it to my system via a switch set up that when thrown, totally disconnects the lithium batteries the instant it connects the AGM batteries and vise versa. I mention that because it sounds similar to what you mentioned you might do.
For me, I couldnt bare the thought of essentially abandoning my still practically new AGMs after converting to lithium. That seemed more waste of money than setting the AGMs up as a "back up" bank. The supplies I needed to set the system up to be able to completely and easily switch from one bank to the other and back cost less than $100.
Thats a pretty decent start youve got there. Ive got a few suggestions that you may or may not find interesting or useful. Firstly, it sounds like you could pair up your panels and connect each pair in series and then all series paired panels in parallel to convert your arrays from 12v to 24v. You could probly get away with connecting ALL your panels to just one controller that way. Save the other as spare or buy more panels and expand your system.
Ok, about that manual transfer switch that you use to flip from inverter to grid. Thats exactly how i started out as well. Then I got tired of having to step out of my RV, walk to the other side where most my electrical is located, flip the switch and then go back inside. Got particularly tiresome in cold weather lol! So heres how I made that all voice controlled from inside my RV. I bought a generator switch that youre supposed to connect to both a generator and grid power and then to your electrical needs. Hooked up "traditionally" the switch automatically flips from grid to generator when it senses no current from the grid. This is supposed to keep you up and running during a power outage. Well, Ive hooked my switch to grid power and to my inverter and kind of "backwards". In my setup, Ive wired the grid to the generator side of the switch and my inverter to the grid side. The results of this causes 120v power to my RV to always come from my inverter UNLESS the switch senses no power from the inverter, at which point the switch autoflips to grid power. To make this all voice activated, I connected the generator switch to my inverter through an Alexa smart outlet. When I tell Alexa to turn off the inverter, the smart outlet cuts power from the inverter to the generator switch and the generator switch immediately flips over to grid power. When i tell alexa to turn the inverter on, the switch thinks main power has been restored and autoflips back to the inverter. Since this doesnt actually turn the inverter "on & off"(just the smart outlet), i can still keep certain loads active by plugging them into my inverters 2nd recepticle. Also, keep in mind that the smart outlets have a load limit of 15amps so you're not going to be able to run an AC through this set up.
