On board air compressor& battery isolator

[Ghostrider I]

91 HDJ80 with dual batteries and auxiliary fuse boxes. Which battery to connect power to run the compressor? Which battery for isolation?

Facing the truck: LS or RS?

 

[ZCissner]

RS

 

[Douglas S]

You can’t isolate a battery with the factory 24v starter setup.

 

[Douglas S]

RS

Facing the truck from the front, all accessories should be run to the LHS battery (RHD driver side),

 

[ZCissner]

Mine is a 12Volt starter, my starter and alternator are both connected to my LHS battery, so wouldn't my RHS battery be for accessories?