Many charging systems offer the ability to program a Low Voltage Disconnect (LVD) or Cut Off (LVCO) which triggers an alternate power source (often a generator) to turn on and begin charging the battery bank. When the programmed low voltage setting is reached, the system initiates the charge source which then safeguards from over-discharge. By default, this may be set by the charger manufacturer at 1.75 volts per cell (VPC). Always verify the default settings and adjust as required.
LVD/LVCO setting is often a personal preference. Deep cycle batteries are intended to be discharged no more than 50%. Allowing the battery bank to discharge to a lower voltage will reduce overall cycle life. Alternatively, a higher set point may result in more frequent use of the alternate charging source (ex: generator) when discharge reaches the low voltage cut-off. To maintain cycle life and prevent heavy discharge, Rolls recommends setting LVD/LVCO between 1.85-1.95 volts per cell (VPC). This may be adjusted up or down, depending how often you wish to run the alternate charging source (generator or alternative power) when the voltage of the battery bank reaches the programmed set point.
WARNING: LVD/LVCO only cuts off the draw from the inverter/ charger. It does not disconnect all loads from the battery bank. A prolonged draw will eventually lead to over-discharge and possible battery failure or damage.