An Introduction to Solar Panel Charge Controllers
January 25, 2022

A charge controller controls the solar array’s output power. Batteries are protected from overcharging during the day and from the power running back to solar panels at night, which might drain them. The primary function of the charge controller is to regulate the flow of electricity, but it can also perform additional functions such as lighting and load control.

Key Features include:

  1. Charging a battery bank in multiple stages: Battery health is improved by adjusting how much power is applied to the batteries depending on their charge level
  2. Protection against reverse currents: When no current is generated from the panels, the battery drains from it; however, these controllers can prevent such.
  3. Disconnect the low voltage: solar controllers are helpful when a battery runs down and reactivates when rechargeable.
  4. The ability to control the lighting: For hours, all night, or anywhere in between, controllers allow you to set the timer.
  5. Display: The controller displays the battery bank’s state of charge, voltage, and the amps generated by the solar panel.

Functions of Controllers

  1. When the battery power rises above a predetermined limit, the most simple charge controller interrupts the circuit and stops the charging process. Mechanical relays are more commonly employed to open or close the circuit, stopping or starting the flow of electricity to the electric reserve devices.
  2. Batteries with 12 volts are commonly used in solar power systems. There is a lot more voltage available from solar panels than is required to charge a battery. The charging voltage can be maintained at its optimal level while charging time is reduced. This function ensures that the solar systems continuously operate at their peak efficiency.
  3. The solar charge controllers can also control the reverse current flow. When panels are not generating any power, the controllers can detect this and block the circuit by disconnecting the panels from the batteries, stopping the reverse current flow.

Types of Controllers

Shunt Controllers 

Shunt control manages the battery’s maximum charge level. Shunt controllers require proper airflow to dissipate heat. When using the shunt controller, excess electricity is diverted away from the Photovoltaic panels and subsequently dispersed through the heating elements after the batteries are fully charged. Overcharging of batteries can also be prevented with the use of these rules.

Single-Stage Controllers

Single-stage controllers in BIPV systems safeguard the batteries by shutting down the charging cycle when batteries are ultimately charged. This control approach sets the battery’s minimum and maximum states of charge, respectively, as the starting and ending points for charging.

The single-stage controller re-establishes the charging circle after depleting the battery to the charge beginning point. BIPV systems managed by this controller can eliminate the demand for ventilation because very little electricity is transformed into heat.

Multistage Controllers

BIPV systems with multistage controllers allow current flow for power supply when the battery packs are at a minimal power state. Photovoltaic arrays can use excess electricity from batteries when nearing maximum capacity. Multistage controllers, like shunt controllers, can extend the life of batteries. Ventilation is also necessary because of the heat generated during power dissipation.