Lithium Battery Help

[chiptown]

Looking for some Electrical/Battery help on a 2014 Bounder 33c. I installed a 204 SOK Lithium battery in the RV. When I connect the Engine battery it trips the BMS in the RV Lithium battery. I was told I need an Isolator to separate the two different types. This will allow the Alternator to charge both batteries. But will not charge the engine battery when plugged in?? It has the Fleetwood F73-1020 Battery Control Center
Has anyone had this problem?
Thanks for any help
Chip

 

[rwilimek]

That is correct, you need a dc to dc charger to interface with the engine battery and the lithium batteries.