I found that the split charge relay keeps the second battery topped up during long drives and cityWhat stands out about this split charge relay is how cleanly it routes power without draining the starter when parked.
KLOCKNER MOELLER Z 2-24/K-NA Bimetal Thermal Overload Relay 3 Pole 16-24A
You will find that the Finder branding stays legible even in a dusty workspace, which I really like.
You will find that the 2 pack is a simple way to cover both old and new setups.