Sun21 MAX-M2024, User Manual

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2) If the controller time is not adjusted, the controller will equalize charge
battery once every month following the inner time.
C) Float Charging
After the Constant voltage stage, the controller will reduce charging current to Float
Voltage setpoint. This stage will have no more chemical reactions and all the charge
current transforms into heat and gas at this time. Then the controller reduces the
voltage to the floating stage, charging with a smaller voltage and current. It will reduce
the temperature of the battery and prevent the gassing and charging the battery
slightly at the same time. The purpose of Float stage is to offset the power
consumption caused by self consumption and small loads in the whole system, while
maintaining full battery storage capacity.
In Float charging stage, loads are able to obtain almost all power from solar panel. If
loads exceed the power, the controller will no longer be able to maintain battery
voltage in Float charging stage. If the battery voltage remains below the Recharge
Voltage, the system will leave Float charging stage and return to Bulk charging stage.