Solar charge controllers (or solar regulators) are one of the most important components of a solar power system. And as the name suggests, a solar controller is used to regulate the amount of charge that goes into the solar battery. It’s job is to ensure that the solar battery doesn’t get overcharged. Besides this, a solar charge controller also prevents reverse current flow from solar battery to solar panel.

This, however, is just the tip of the iceberg and you may want to know more about solar charge controllers. And therefore, in this post, we will discuss in detail the functions and types of solar charge controllers.

Let’s read on.

What does a solar charge controller do?

We just mentioned the two main functions of a solar charge controller- preventing batteries from getting overcharged and preventing reverse current. Now let us look at these two functions in detail.

  1. Prevent battery overcharge

The solar panels produce a large amount of energy. This energy gets transferred to the solar battery for storage. However, the battery has a certain storage capacity and if it receives charge beyond this maximum capacity it will get damaged because of overcharging. In fact, chances are that the battery might even explode. This is where a solar charge comes into play. The solar charge controller prevents overcharging of batteries by reducing or completely cutting off the flow of energy to a battery when it reaches a certain voltage.

  1. Prevent reverse current

Typically, the solar panels generate energy and pump it into the solar battery. However, during the night there may be a reverse current flow from the battery to the solar panels. This can cause damage to the solar panels. It is to prevent this reverse flow of current, that we require a solar charge controller. In most charge controllers, the energy passes through a one-way valve (semiconductor) that prevents charge from flowing back into the solar panels.

Types of solar charge controllers – PWM and MPPT

Solar charge controllers can be divided into two types based on the technology they use.

  • PWM (Pulse Width Modulation) Charge Controllers
  • MPPT (Maximum Power Point Tracking) Charge Controllers

PWM Charge Controllers

PWM stands for “Pulse Width Modulation”. PWM charge controllers are like a switch that directly connects the solar array to the battery bank. PWM charge controllers are mostly for small off-grid power systems and are more cost efficient (as compared to a MPPT charge controller).

How does a PWM charge controller work?

As we know the solar panels and the battery need to be at the same voltage for charge transfer to take place. But as the solar panel’s voltage is usually more than that of a battery, the PWM charge controller brings down the voltage of the solar panels to facilitate charge transfer. However, since the panel’s voltage is pulled down from its operating operating voltage (Vmp) which in turn leads to reduced power, this isn’t considered a very efficient way of charge transfer.

MPPT Charge Controllers

MPPT stands for “Maximum Power Point Tracking”.  Unlike PWM charge controllers that pull down the voltage of solar panels, the MPPT charge controllers allow solar panels to work at their optimum voltage. Since they use a smarter technology they are more expensive as compared to PWM controllers and are therefore recommended for high power systems with 2 or more panels.

How does a MPPT charge controller work?

The MPPT charge controllers continuously track the panel voltage and ensure the best combination of panel voltage and current so that it generates the maximum power possible. They bring in maximum power from the solar panel and then vary their output voltage to match that of the battery. And in case the voltage needs to be stepped down, they increase the current in order to ensure maximum power output.

Investment in a solar charge controller is a one time investment, and therefore, you need to make sure that you choose the right solar charge controller for your home. So if you have made up your mind and are looking for help, we suggest you get in touch with a solar expert at Luminous India. They will not help you choose the right solar charge controller, but will also clear your doubts, if any.