Solar charge controller is the central component in a Solar Home System (SHS) also called (Off-Grid). It controls the energy flow in the entire system and determines the system function. This means that a suitable solar charge controller must be selected carefully, and yet it is also one of the most important component in the system. as it increases the battery life and thus leads to a significant saving in system costs.
The main function of a charge controller is to regulate and protect the battery from overcharging and also block a reserve current flowing back from the battery to solar panels when there is no sun shining example in the night. (discharging). If a non-self -regulating solar array is connected to lied acid batteries with no overcharge protection, the life of the batteries will be compromised.
Types of Charge controller
Series controllers When the charge cut out voltage is reached, a series controller interrupts the module power using relay or power conductor and switches it back and after defined voltage drop.It disables further current flow into batteries when they are full.
Shunt controllers A shunt controller continously reduses the module power when the charge cut out voltage is reached . But since the module contioues producing power, the unneeded part of the module’s power is used as a short-circuit current without any problems. This medthod is ideal for the battery as charging is safe and swift.
MPPT Maximum Power point Tracking: MPPT solar charge controllers make the solar panels operate their optimum power output voltage. The current is regulated by the battery voltage, therefore they make the system accept high input voltages from the solar array. The generated power is able to be used more efficiently.
PWM Controllers Pulse Wide Modulation is a special charging algorithem that is used in most charge controllers and also in other electric devices. It is the most effective means to achieve constant voltage battery charging by switching the solar system controller’s power devices .
When a battery voltage reaches the regulation set point , the PWM algorithm reduces the charging current to avoid heating and gassing of the battery. The result is a higher charging effeciency, rapid recharging , and a healthy battery at full capacity.