What Is a Solar Charge Controller?

What Is a Solar Charge Controller?

A solar charge controller is a necessary part of any off-grid solar panel system that uses batteries. They prevent stored energy from flowing back into the panels when the sun isn’t shining.

Simple PWM (Pulse Width Modulation) solar charge controllers make a direct connection between the array and battery. Then they use a basic rapid switch to modulate battery charging.

Battery Charger

A battery charger is an essential part of any solar power system. Without it you risk overcharging or even damaging your batteries. This is because solar panels produce a lot of current. The charge controller “looks at” the panel output voltage and regulates it to avoid overcharging your batteries. Some controllers do this by switching the current on and off, others use a faster pulse method. The more advanced MPPT (Maximum Power Point Tracking) controllers are the best choice.

The MPPT controllers have sensors that determine the optimum working voltage of the solar panel and down convert it to the battery. This means more power is used by the battery, and it also prolongs battery life. These advanced controllers are available from Inverters R Us in a variety of sizes.

Most modern charge controllers come with a display that shows battery voltage, state of charge, and amps coming in from the solar panel. They are also available in different configurations depending on your needs. For example, some models have DC load terminals which allow you to connect a light or other device. These are useful for off-grid applications where you want to control a load based on dusk and dawn. They are not required for most smaller systems, though. The simpler PWM (Pulse Width Modulation) controllers do not have these features, but they are much cheaper and reliable.


A solar charge controller prevents electricity from flowing back into the solar panels at night. Since electricity always flows from high to low voltage, if there was nothing in place to stop it, energy would flow into the solar panel at night when the sun isn’t shining and cause damage. The charge controller has a solar charge controller 12v diode that only allows power to travel one way, keeping the energy from feeding back into the panels.

It also manages how much power is being fed into the battery, ensuring that it doesn’t overcharge. The amount of electricity a charge controller will send to a battery depends on its current (amperage) rating. Typically, the higher the rated current, the more powerful the controller. If a solar charge controller is rated at 30 amps, it will only allow up to that much power into the battery at any given time.

Another function of a solar charge controller is to detect when a battery is getting low and shut off the solar panel output in order to protect it from being completely drained. This is accomplished through a circuit called forced commutation.

A few of the more advanced solar charge controllers on the market have a display that shows essential information about your system. You can see things like the state of the battery, how much solar energy it is generating at any given moment, and more.

Lights & Appliances

The charge controller sits between your solar panels and battery storage system, monitoring the voltage of the batteries and preventing them from being overcharged by reducing the flow of energy once they reach a set voltage. Overcharging can damage your battery and Solar Inverter shorten its lifespan. Most charge controllers also offer overload protection, low voltage disconnects and blockage of reverse currents.

You can also purchase solar charge controllers that have built-in load control functions. This allows you to connect a DC load, typically a light, and program the charge controller to turn the light on and off at different times of the day. This avoids power drain from the inverter for lighting that is used long hours.

Our range of controllers feature both Pulse Width Modulation (PWM) and Maximum Power Point Tracking technology. MPPT technology automatically maximises the solar panel output for all weather conditions, delivering the most efficient performance and boosting your solar energy yield.

When selecting a solar charge controller, you need to consider how much current your system can draw, the max charge current of your batteries and whether there are any other DC loads connected. For example, if you are using a DC water pressurising pump and a light that draws 10 amps or more, you need to select a controller rated for this capacity.

Solar Panels

When connected to a battery, solar panels produce voltage. The controller prevents the battery from overcharging by directing the correct amount of power into the battery at all times. Without the controller, the panels could overcharge a fully charged battery by generating more voltage than it can process and can even damage the panel itself. It also detects a low battery and disconnects the load.

There are many different types of solar charge controllers, and most of them are based on PWM technology. These simple controllers connect directly from the solar array to the battery and use a basic rapid switch to modulate or control the current. They’re inexpensive, reliable, and effective in small systems.

A more sophisticated MPPT solar charge controller can take excess voltage from the PV array and convert it to usable DC power at the battery. It can also step down the battery voltage to match its optimum operating (Vmp) voltage and increase the efficiency of the system by using more of the PV energy.

Solar charge controllers are a must-have for almost all solar power applications. They protect the batteries, increase the amount of electricity that can be extracted from the solar array, and help ensure that the solar array is matched and compatible with the battery bank. They also block current from flowing back into the solar panel at night.

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