Hello Oildrums.
This thread may assist if you have dual battery system in ute tray, but I guess it depends where you have you dual battery system installed.
Mine is under bonnet, using InterVolt DCDC charger (Western Au manufacture) and 70AH battery installed there.
Installed cable from bonnet, through Chassis (when has plenty of holes to assist guiding cable through), and up between cab/canopy, left loose between, but nylon tied at base and at top to rhino rack. Cable is multi-stranded auto double insulated. Used male/female weather proof anderson plugs nylon-tied to rhino rack.
Have had no troubles with being loose between cab/canopy.
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