It is highly recommended for 24V system and required for 48V* and 120V* systems.  The Battery Sense wires, as well as reading the battery terminal voltage, provide a protective inverter pre-charge function for the internal capacitors.  This pre charge, minimises surge current feeding capacitors and protects DC switch gear from arching during initial switch on.

If you choose not to install the sense wiring, then link wires must be fitted to clear the Service Required alarm.

* Some Battery Managements systems provide a pre-charge function when the battery banks turns on, in these case, there is no requirements for the battery sense wires to be fitted.