The white strip is just a terminal block to connect wires together. The black box is either a solenoid for controlling a high amperage device or a voltage sensitive relay that charges another battery
when a charging
source is present. Do the thick blue wires lead to a windlass
or electric winch
, or do all wires lead to batteries
My guess is a reversing solenoid for a windlass
- the small black wire is the ground and the two orange wires are the forward/back control.