How to Select a Solar Charge Controller

Solar energy is all the rage these days. Along with being a clean energy source, it also reduces your energy bills. As a result, more and more people are adopting solar and going green. Despite its increasing popularity, there are still lots of confusing aspects to solar energy.

Many people want to take a DIY approach to solar panels. While setting up solar panels is much easier and cheaper than it once was, it can still be a tricky proposition. This is especially true if you don’t understand the various components and what they do.

A solar charge controller is one such component. Today, we’ll look at how to select a solar charge controller. To do so, we’ll look at what it is, how it works, and its two main types.

What is a Solar Charge Controller

A solar charge controller is an integral component of any solar panel system. It reverses the flow of current from your solar panel into the batteries at night. It also manages the charge going into your batteries to protect them, and prevents overcharging.

The solar charge controller has a transistor through which it can divert the current in the photovoltaic circuit. In doing so, the controller makes sure your batteries never overcharge or completely discharge. Both situations can reduce the batteries life.

The charge controller allows your entire system to last longer by saving it from shocks, and increasing efficiency.

Types of Solar Charge Controller

When trying to figure out how to select a solar charge controller, you’ll see that there are two main types. This is despite the variety in prices, specifications, and power ratings. The two types are Pulse-Width Modulation (PWM) controller and a Maximum Power Point Tracking (MPPT) controller.

It is important that you make the correct choice. This is because choosing one that isn’t suitable for the job could potentially result in you losing 50% of your solar energy. The two determinants for the size of the solar charge controller are the current in the solar panels, and the entire system’s voltage.

Your choice should be one that is capable of dealing with the current and power generated by your panels. It’s important to have made all the calculations regarding your system in advance. You can’t make a decision on the solar charge controller until you know how much current and voltage your system will produce.

Select the Right Charge Controller

Now let’s dive into how you can select the right solar charge controller for your system. The decision will be based on what type of controller you plan on getting. So, let’s take a look at both PWM and MPPT charge controllers and how to size them.

PWM Charge Controller

PWM controllers utilize the from the current solar panels and cannot limit their current output. What this means is that if the controller is rated for 40 amps but your array is producing any more than that, your controller could suffer serious damage.

It would be pointless to use a PWM controller that isn’t matched in terms of amps with your panels. You’ll just have to go buy another one when the current one is inevitably damaged. You should always look at the voltage and amp rating before purchasing a PWM charge controller.

The voltage for the entire system tells us whether the charge controller will be compatible with the battery or not. If it you forget this check, your charge controller won’t even work. This happens if the voltage is much higher than the controller is rated for.

We also inspect the current that the controller is rated for. If the system produces more current than the charge controller can handle, it won’t function properly as it is simply not rated for it. It is better to select one with a higher rated battery current.

You already know that you have to make calculations in advance to see how much voltage your system will produce. These calculations should be the basis for you decision again. Your controller can handle a maximum amount of voltage running through it, so ensure that your system produces voltage below this value.

MPPT Charge Controller

An MPPT charge controller overcomes some of the limitations present in the PWM controller. One of the improvements is the ability to limit output. This means that the size of your solar array isn’t of immense consequence, and regardless of how much current it produces the charge controller will simply limit it.

By limiting the output, your controller will prevent damage to itself and the batteries, and continue to work without a hitch. The problem; however, is that the system will be incredibly inefficient. All that extra energy that your array is generating is simply being wasted because your controller is limiting it.

The amp rating on the charge controller should indicate the amount of current it will allow. So, if your system produces more than that, it will simply be wasted. As such, you should try to match the amp rating on the controller to the system’s current.

MPPT charge controllers have a special ability that gives it the edge of PWM charge controllers. They can adjust the voltage input to the level required by the battery bank. It can increase the current to substitute the lost power.

Our Final Thoughts

Solar energy adoption is on the rise. If you want to join the movement it important to know answers to questions such as how to select a solar charge controller. Now that you know, you’ll be able to make the best decision for yourself and enjoy the savings that come with solar power.