Four Charging Stage - opti-solar SC MPPT series User Manual

2.3 MPPT—Four Charging Stage
Magic series controller has a 4-stage battery charging algorithm for rapid, efficient, and safe battery charging.
MPPT Charge
In this stage, the battery voltage has not yet reached boost voltage and 100% of available solar power is used to recharge
the battery.
Boost Charge
When the battery has recharged to the Boost voltage setpoint, constant-voltage regulation is used to prevent heating and
excessive battery gassing. The Boost stage remains 120 minutes and then goes to Float Charge. Every time when the
controller is powered on, if it detects neither over discharged nor overvoltage, the charging will enter into boost charging
stage.
Float Charge
After the Boost voltage stage, the controller will reduce the battery voltage to Float voltage setpoint. When the battery is
fully recharged, there will be no more chemical reactions and all the charge current transmits 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 battery and prevent the gassing, also 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 stage, loads can continue to draw power from the battery. In the event that the system load(s) exceed the solar
charge current, the controller will no longer be able to maintain the battery at the Float setpoint. Should the battery
voltage remains below the boost reconnect charging voltage, the controller will exit Float stage and return to Bulk
charging.
Equalize Charge
Certain types of batteries benefit from periodic equalizing charge, which can stir the electrolyte, balance battery voltage
and complete chemical reaction. Equalizing charge increases the battery voltage, higher than the standard complement
voltage, which gasifies the battery electrolyte. If it detects that the battery is being over discharged, the solar controller
will automatically turn the battery to equalization charging stage, and the equalization charging will be 120mins.
Equalizing charge and boost charge are not carried out constantly in a full charge process to avoid too much gas
precipitation or overheating of battery.
WARNING: Risk of explosion!
Equalizing flooded battery can produce explosive gases, so well ventilation of
battery box is necessary.
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