What is a Solar Charge Controller

Solar panel systems will frequently require a circuit that helps to control and maintain its battery health. To that means, it is essential that we know what the solar charge controller is.

In this post, I’ll explain all you need to know about solar charge controllers using the simplest terms.

You could have previously misidentified the solar charge controller as the solar panel itself.

Typically, people think of solar as a large blue and black panel on the roof (solar panel).

Most people are unaware that a regulator – known as the solar charge controller – is always present between the panel and the batteries.

If you’re interested in learning more about these solar charge controllers, keep reading as I go through some of their key features.

I will also walk you through how to install a solar charge controller and tell you exactly how it works.

Without wasting any more time, let’s get right into it.

Solar Charge Controller; What Does it Mean?

What is a Solar Charge Controller; What Does it Mean

A solar charge controller regulates the way your batteries charge. Batteries with these buffers are protected from overcharging and over-draining.

They direct electricity from your solar panels to your battery.

Solar charge controllers play a key role in solar energy systems. The device monitors parameters such as voltage, current, and temperature.

One of the advantages is that it tells the solar panel system when to turn on or off the charging. As a result, your batteries will not be damaged.

Additionally, they help to extend the battery’s life and preserve its capacity. As I hinted earlier, these devices are important to the proper functioning of your solar panels.

Solar charge controllers are expensive, so you may want to consider your needs before deciding on whether to purchase them.

Depending on your requirements, a basic buck converter may be sufficient. However, switching DC to AC necessitates more robust circuitry, which is best handled by a charge controller.

Regardless, the solar charge controller is a component that’s totally worth investing a few hundred dollars in. Discovering the best solar charge controller can feel like you have just acquired pure gold.

Let’s face it, solar power doesn’t come cheap!

Charge controllers are available in different types, ratings, and with different features. To help clarify, let’s take a look at how each type of charger works.

How Does a Solar Charge Controller Work?

How Does a Solar Charge Controller Work

Understanding what solar charge controllers do is the best way to determine how they work. The job of the solar charge controller is to take electricity from your solar panels and regulate its flow to your battery bank.

The charge controller will prevent overcharging and reverse current flow, both of which can be damaging to the batteries and cause them to fail earlier than expected.

There are many different types of solar charge controllers that vary in style and number of functions they provide, but all have the same task: keeping your system running at peak performance by preventing damage from an excess voltage or current.

Ultimately, a solar power system needs the means to measure how much electricity it has generated thus far.

On an LCD display, scrolling bars indicate how much power each component generates and consumes.

You can see how much electricity is consumed from your outlets as well as how much power is coming from the solar panels and going into the batteries (if any).

Your battery’s current state of charge is also displayed on this screen.

The controller measures voltage and current data to determine total system performance at any given time. If there were no controllers, it would be difficult to know which components are working and which aren’t.

When charging a battery with an overabundance of energy coming in from solar panels, a controller acts as a sort of gatekeeper that prevents damage by sending excess energy back out into the system via the “dump load.”

There is one more function that we haven’t talked about yet. The controller can also prevent overcharging of your batteries.

Overcharging may destroy batteries, which is why you should always monitor the charge on your battery. If it becomes too low or falls below 50%, immediately ceases using that device until it is fully charged.

I believe you now know how a solar charge controller works. right? Let me walk you through a very essential part of the decision-making – choosing the right solar charge controller.

Choosing a Solar Charge Controller.

If you’re using multiple panels and/or multiple voltages (12V and 24V) for your system, make sure your controller can handle both types.

For example, if you have 12V panels hooked up to a 24V battery bank, you’d want either two 12V controllers or one 24V controller with two outlets.

In many cases, it’s more cost-effective to get a 24V controller and two outlets so you don’t have to change the wiring on your system later—as long as you need both 12V and 24V charging.

If you want a solar charge controller that is easy to use, make sure it comes with features like USB integration for battery monitoring or Bluetooth connectivity. Also, make sure it displays live data about your system.

However, you should be prepared to pay more than $100.

It will probably take a little trial and error before you figure out which one has all of the features you want at the price you’re looking for. Still, it will be worth it eventually.

Types of Solar Charge Controller

Types of Solar Charge Controller

Charge controllers can come in several different forms:

PWM Pulse Wave Modulation

These are the most typical charge controllers seen in small off-grid devices powered by 12v batteries. They are easy to install and maintain, however they are less efficient than MPPT (Maximum Power Point Technology) Solar Charge Controllers.

This means you’ll need bigger panels to produce the same amount of power as an MPPT controller will.

There are also a number of benefits to using a PWM charge controller aside from the cost-saving benefit. In general, PWM controllers are less complex and more rugged than MPPT panels.

This makes them easier for garden-variety users to maintain without having to hire an electrician or other specialist – you can typically do everything yourself with a set of decent instructions and a basic knowledge of electricity.

Furthermore, Pulse Wave Modulation Solar Charge Controllers offer faster charging times because they use lower voltage levels. This means that it’s possible to have higher current levels at the same time.

Note that this will be an issue if you have multiple panels wired into one bank or if your panel(s) can provide more power than your battery bank can store.

To read more on PWM solar charge controllers, you can visit our 5 Best PMW Solar Charge Controllers

MPPT Maximum Power Point Technology

These charge controllers are intended to get as much energy as possible from your panels. As a result, they outperform PWM pulse wave solar charge controllers (at around 97 percent ).

Besides, you’ll need fewer panels than you would with a PWM charge controller in order to produce the same amount of power.

They also have some other advantages over PWM controllers, but this is by far their biggest advantage! However, the MPPT comes at a big price.

This is because they require more expensive equipment than standard cheap PWM controllers.

Furthermore, when it comes to MPPT solar charge controllers, there’s something you need to know. It is advisable to wire your solar panels in series rather than parallel.

Why? This is because MPPT use panel efficiency to maximize power input and can be a problem if you have multiple panels wired into one bank.

The ability of an MPPT controller to alter the voltage/current curve of a given solar panel also means that you need less total solar capacity when wired up in parallel.

This comes with its own set of drawbacks. Not only will your equipment cost more, but the higher current levels coming from each individual panel could mean that they wear out faster or require more attention from users.

You can read more about MPPT solar charge controllers on our 5 Best MPPT Solar Charge Controllers page

In summary: Pulse Wave Modulation Solar Charge Controllers are cheaper, easy to maintain, and provide the quickest charging times, but they can’t handle as high of load currents or work with as many panels, and require the use of diodes to prevent reverse current flow.

Meanwhile, Maximum Power Point Technology Solar Charge Controllers are more expensive. The good thing about them, however, is that they reduce the number of solar panels required for a given charge current by 50%.

They also offer lower system maintenance costs than PWM controllers and provide more accurate battery charging at the cost of long charging times.

How To Size Your Charge Controller

How To Size Your Charge Controller

Choosing the right size charge controller for your solar system can be difficult. How do you know if it’s too big or too small?

What would a bigger charger cost me, and how much power will it provide? What is the output of my solar array in amps?

These are all questions we’ll answer in this article so you can make an informed decision about what size charge controller to buy.

For help sizing your charge controller, read on!

When it comes to charging controller size, you must consider whether you’ll be utilizing a PWM or an MPPT controller. A poorly chosen charge controller can result in a loss of up to 50% of the solar power generated.

Charge controllers are sized based on the current and voltage of your solar array. How do you know if your charge controller is the right size? How do you know if it’s too big or small for your needs?

Typically, a 12-volt solar panel produces between 20 and 40 amps of current. If your array can produce 80 amps of power at 12 volts DC, then you’ll need a 48 V charge controller to protect your system from overcharging.

In reality, the amount of power the solar array generates is measured in watts. What is the amount of power my solar array produces in amps?

A single 100-watt panel, for example, will put out about 17 amp-hours per day if it’s facing south and around 13-15 under other orientations (north or east).

How Much Power Will I Get?

A larger charge controller can be beneficial, but they do come at a higher price. It’s better to use a smaller size charger if you aren’t going to use the power that your panel is generating. Hence, saving you money from energy production.

A good rule of thumb for sizing your panels and/or chargers is to take their maximum capacity and divide by two. This will give you an ideal size range for each component in the system.

The amount of amps produced by your solar array depends on its wattage rating as well as sunlight exposure over time.

This number may vary based on where you live and the season, so it’s a best practice to just go with what works best for you rather than trying to guess/figure out what you’ll be producing throughout the year.

A 100 watt charge controller is sufficient for a 200-watt solar array exposed to full sunlight for over eight hours per day.

However, this may vary based on where you live or how long of an exposure time you have each day.

If possible, go with something larger just in case because more power means better efficiency!

In addition, if cost isn’t a concern when choosing a charger, going for a large one will give you more flexibility. It will take into account things like imperfect weather conditions or less than ideal sunlight exposure times.

You’ll also get more power out of your system.

You should also know the wattage of each panel when choosing a charge controller for your solar array. Then, you can accurately determine how much power your panels can generate at any given time.

Before deciding on a charger, it is also important to consider the voltage and current source you have.

For instance, if there is one 100-watt panel and four 50-watt panels, a 500-watt charger is sufficient. It depends on where and when it is used.

In either case though – whether going large or staying safe by going smaller. You’ll want to know how many amps each panel produces before making anything final.

You can do this by measuring the voltage and current of your solar array.

You should also know how much extra power a larger unit will add to what you’re already producing.

Knowing this will help you determine whether or not it is worth buying a slightly more expensive model – with a higher wattage capacity. This way, you won’t have any surprises in terms of having too little juice when you need extra.


 Solar Charge Controller; Conclusion & Reconmendation

Is it worthwhile to invest in solar charge controllers?

Solar charge controllers provide convenience to customers, so they are definitely worth the investment.

The best charge controller can help you stay out of power failure. It also slows down the rate at which your solar panel batteries become overcharged or undercharged.

Ideally, they are like the ultimate gatekeepers that help sustain your solar panel batteries’ health for as long as possible.

In conclusion, the two solar charge controllers we’ve examined are effective since they ultimately serve the same purpose quite well.

You can preserve your solar battery by controlling how much energy gets transmitted to it through these controllers.

As for us, the solar charge controller at the top of our review stands out as the number one option.

I hope you like this PowerVersity selection.

We appreciate your feedback, so please make use of the “Leave A Reply” form found below.

Finally, to read more guides like this, visit our Inverter & Charge Controllers page.

Victor Akin-Ojo
Victor Akin-Ojo is the founder and the Lead Editor of PowerVersity.com. Before he started PowerVersity.com, Victor worked in the IT industry for close to 15 years. He worked mainly as field Engineer on Installation of VSAT, Wimax Technologies, including but not limited to, Power Maintenance Sector for close to 10 years – Designing an electrical installation for Homes, Private and Government Offices and more.
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