Does the tow vehicle fully charge RV lithium batteries? : r/rvlife
When I swapped my house battery to lithium I removed the charging wire for the 7 pin so that while I''m parked with the 7-pin connected the lithium battery wouldn''t drain the starter battery in my truck. If you really want to charge your lithium through the 7-pin I recommend getting a dc-dc converter so it won''t kill your starter battery.