Service Manual: SC750, SC800, SC 750 ST, SC800 ST
Form Number 56043150 Page 45
On-board Battery Charger
An oponal on-board baery charger is available. When equipped, it is mounted on the boom of the machine. The
charger has an internal relay that interrupts power to the on-board when the charger is plugged into an AC power outlet.
This is called the “Interlock” circuit on the wiring diagram. It prevents the machine from being operated while the bat-
teries are charging. Wiring changes must be made when installing the baery charger for the interlock circuit to work
correctly.
Here is how the baery charger interlock circuit works. The interlock relay contacts inside the charger are normally
closed, allowing the current to pass in and out of the charger to the On-board and the Drive Motor Controller. When the
AC power cord is plugged in, the relay is energized and opens the relay contacts opening the circuit.