Adopting solar panel systems is the wisest choice we can make today but gathering information about the basics is important before that. Different types of solar charge controllers are also one of the components of the PV system. Let us find out in detail about them.

What is Solar Charge Controller?

It is a regulator for the solar battery that prevents it from overcharging. Solar charge controllers are a gateway to the battery storage system. They ensure there is no damage to batteries from overload or overcharge and are especially required with an off-grid solar system. MPPT and PWM are the most known types of solar charge controllers.

What are the Types of Solar Charge Controllers?

JAN23 What are Different Types of Solar Charge ControllerBasically, there are 4 types of charge controllers.

1. MPPT Charge Controller

It allows the voltage from solar panels to vary from the battery voltage. The Maximum Power Point Tracking (MPPT) can identify the point of maximum power production by solar panels with their varying array input function.

They break the circuit between the solar panels and batteries, thus effectively protecting the system. MPPT controllers are preferably used for negative ground systems as they use a negative line reference and then switch back to the positive line.

Limitation – Heat dissipation is a common problem with MPPT charge controllers, especially when used in large solar arrays.

2. PWM Regulator

These regulators work constantly like a rapid on/off controller and self-adjust by varying the speed and width of the pulses sent to the battery. At 100% width of the transistor solar panels charge the solar battery to the fullest but with 0% width, the transistor is off.

This prevents current flow from panels to batteries. This mostly happens in the case of overvoltage supplied or when the battery is fully charged. Some PWM regulators can be converted into series regulators for sensitive loads if they have an issue with the sound generated from PWM frequency. PWM controllers are similar to series regulators but do not use transistors.

Limitation – PWM regulators also cannot withstand extremely high temperatures.

3. Series Regulator

This solar charge controller opens the circuit after the battery reaches a set voltage. It then allows current flow between batteries and solar panels, until it again reaches the disconnect voltage (high temperature). A series regulator uses a relay or transistor to connect or disconnect solar panels with batteries.

These charge controllers can be used in both ground systems (negative and positive). Series regulators are also known as a type of on/off regulators and with them, batteries will either have full current or none.

4. Shunt Regulator

They short-circuit solar arrays as and when batteries reach a set voltage. Also known as pulse regulators, they are single-state charge controllers which work by turning charge regulation on/off.

Shunt regulators also have a transistor along with a blocking diode. The former breaks or connects the solar array with batteries whereas the latter protects the battery from short circuits, simultaneously.

These types of solar charge controllers are ideal for negatively grounded systems as their blocking diode is in the positive diode. This makes them ideal for small PV systems.

Also SeeSolar Charge Controller Settings

What are the Functions of Solar Charge Controllers?

Here is a list of functions performed by types of solar charge controllers.

  • Battery Open-Circuit Protection: After the battery is normally charged, the voltage will be limited across the load to ensure that neither the load nor the battery is damaged.
  • Daylight Control: When used with solar lights, during daytime (good sunlight) the charge controller automatically turns off the load output. After sunset, it automatically turns on the load due to which solar lights automatically turn on at night and off in the morning.
  • Lightning Protection: During thunderstorms, the chances of lightning strikes increase if your solar panels are mounted high. In case of a lightning strike, high voltage is supplied through wires that batteries and loads cannot handle. Charge controllers break the circuit to prevent this high voltage from reaching the solar power system and its devices.
  • Load Short Circuit and Overcurrent Protection: Usually, solar batteries are 12V so once the load current exceeds 10A or more, the load is short-circuited. Breaking the circuit fuse blows off. That can be replaced, and your solar charge controller is good to use.
  • Overcharge Protection: If the charging voltage (DC) is higher than the protection voltage, the charge controller will automatically disconnect the battery from a power source (solar panels) to prevent it from overcharging.
  • Over-Discharge Protection: When the battery voltage is lower than the protection voltage, the charge controller disconnects the battery from the load and protects it from discharge or over-discharge.
  • Overvoltage Protection: When the voltage is too high, solar charge controllers turn off the output automatically. It controls the voltage and opens the circuit when the battery voltage reaches an optimum level.
  • Reverse Battery Connection Protection: In case the polarity of the battery is reversed, charge controllers help in preventing any functionality. Once the polarity is corrected, a battery can be used.
  • Self-Checking Function: If the charge controller is not functioning properly due to internal or external factors, the controller performs a self-check. It then sends signals and warnings to the user through monitors and phone applications.
  • Temperature Compensation: Solar charge controllers monitor the temperature of the battery. If the temperature is not ideal, then it regulates the charge and discharge value making it ideal for the battery to function.

Understand more about solar charge controller load output.

What are the Applications of Types of Solar Charge Controllers?

Do Solar Lights Charge on Cloudy Days 1

With increasing users of solar panel systems, solar charge controllers are also in high demand. Usually paired with an off-grid solar power system, a solar charge controller can be used in different applications.

  • Hybrid solar power system (residential)
  • Small solar power systems use Pulse Width Modulation (PWM) charge controllers.
  • Solar street lamps and solar lights
  • Wind power turbines and small water turbines use Maximum Power Point Tracking (MPPT) charge controllers.

Can I Use Solar Panel Without Charge Controller?

Yes, technically you can use PV panels without a charge controller and connect them directly to the battery. Generally, it is advised to use solar panels with a charge controller. However, the following conditions can be considered as exceptions.

  • With low-power rating solar panels you can omit the charge controller. This will not likely do any damage to the battery because its operating voltage reduces once connected to the battery.
  • Battery and panel voltage synchronize, which means panel voltage output and battery voltage input are almost the same.
  • In case you are trickling charging a battery from solar panels around 5W.
  • Use USB ports on solar panels because panels have integrated smart IC chips that regulate the voltage supplied to your device thus protecting them from over or undercharges.

IMPORTANT – If a panel emits 2 watts or fewer for every 50 battery amps-hour, then as per the general rule a charge controller is necessary.

So, with different types of solar charge controllers, we can protect our PV systems. Although MPPTs are considered the most effective, others are also good depending on the type of system and power we use. Explore our website for more useful information on solar panel systems, components, and related topics.

Recommended: What Size Charge Controller For 600W Solar Panel?

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Olivia is committed to green energy and works to help ensure our planet's long-term habitability. She takes part in environmental conservation by recycling and avoiding single-use plastic.

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