Isolating TT's Lithium from TV's Lead Acid Batteries

IHMO High dollar lithium batteries should be properly charged and a flooded battery alternator does not do that. Plus the TV battery/alternator voltage is not the voltage at the end TT end of the wires. Often TV and TT wiring is adequate for small loads like a propane refer and inadequate charging.

Typically the starting battery is quickly charged and the voltage drops to 13.6V or so regardless of the TT battery charge on the end of those long wires.