RD Series Owner's Manual - Magnum Energy

Operation
The Charge Mode provides up to four separate charging stages: Bulk Charging, Absorb Charging,
Float Charging, and Full Charge (see Figure 3-3).
Bulk Charging: This is the initial stage of charging. While bulk charging, the charger supplies the
battery with constant current. The charger will remain in bulk charge until the absorption charge
voltage (determined by the battery type selection*) is achieved. The inverter’s green LED stays
ON (solid) to indicate bulk charging.
Absorb Charging: This is the second charging stage and begins after the absorb voltage has
been reached. Absorb charging provides the batteries with a constant voltage and reduces the DC
charging current in order to maintain the absorb voltage setting. The inverter’s green LED flashes
once every second (medium flash) to indicate absorption charging for 2 hours (determined by the
Battery AmpHrs selection*), then switches to float charging.
Float Charging: The third charging stage occurs at the end of the absorb charging time. While
float charging, the charge voltage is reduced to the float charge voltage (determined by the
battery type selection*). In this stage, the batteries are kept fully charged and ready if needed by
the inverter. The inverter’s green LED flashes once every 8 seconds (slow flash) to indicate float
charging. The Float Charging stage reduces battery gassing, minimizes watering requirements (for
flooded batteries), and ensures the batteries are maintained at optimum capacity.
Full Charge (Battery Saver mode): The fourth stage occurs after four hours in the Float
Charging stage. The Full Charge stage is designed to keep batteries fully charged over long periods
and prevent excessive loss of water in flooded batteries, or drying out of GEL/AGM batteries. In
this stage, the charger is turned off and begins monitoring the battery voltage; if the battery
voltage drops low (12.7 VDC or less on 12-volt models or 25.4 VDC or less on 24-volt models),
the charger automatically initiates another four hours in float charge.
Info: If the battery voltage falls to the re-bulk voltage (12.1 VDC on 12-volt models or
24.2 VDC on 24-volt models) or lower, the unit will begin another bulk charge.
* These settings in the RD Series are changeable and leave the factory with default values (see Table
3-2, Inverter/Charger Default Values). These default values are adequate for most installations,
however, if you determine that some of the values need to be changed for your particular system,
the ME-RC50 remote control may be purchased to adjust these settings.
Bulk
Charging
Absorb
Charging
Float
Charging
Full
Charge
DC
Voltage
Time
Increased
Voltage
Absorb
volts
Constant
Voltage
Float
volts
Reduced
Voltage
Monitored
Voltage
DC
Current
Max
Charge
Rate
Absorb
Time
Goes to Full
Charge after
4 hours in
Float Charge
Constant
Current
Reduced
Current
Monitored
Current
No Current
Figure 3-3, Automatic 4-Stage Charging Graph
© 2010 Magnum Energy, Inc.
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