I just want to reiterate that you really need someone that knows what they are doing installing both solar and Lithium batteries, improperly installed solar can cause roof leaks that leads to wood rot, which leads to towing what may have otherwise been a good RV to the junk yard. Improperly installed Lithium batteries can lead to electrical shorts, fires, and loss of the RV and perhaps loss of your life. Way too many people treat Lithium batteries of any type including LiFePo4 like they would treat lead acid batteries, this is wrong on several levels, one notable way is in the required fusing for safety in case of a catastrophic wiring short, this can be bad enough with lead acid, but can be way worse with Lithium due to their much lower internal resistance, as they can release an immense amount of power in an instant destroying themselves as they do so, vaporizing wires, and splashing molten metal everywhere. Main fuses like Mega Fuses with an interupting capacity of 2,000 amps or ANL fuses with an interupting capacity of 2,700 amps may be fine for Lead Acid batteries in case of a short, but for Lithium which can potentially output 15,000 amps or more for a fraction of a second you really need the expensive class T fuses rated at an interupting capacity of 20,000 - 60,000 amps.
Sure that 200 amp rated Mega Fuse will blow in case of a dead short on a LiFePo4 battery cable, but it will then instantly vaporize and likely not extinguish the arc, it will in effect be like striking an arc on an arc welder which will continue to arc for some seconds until either the BMS disconnects the load, or the battery self destructs.
In other words, don't let your typical RV shop mechanic that only knows what he has read on the side of the label install Lithium batteries in your RV.