Finding the best solar charge controller is a crucial step when setting up a proper solar system. At first glance, this device might seem irrelevant within a solar system; however, it fulfills a crucial function: regulating the voltage and current to protect your batteries.
You’ll see that not every system requires a solar charge controller, and not all solar systems require the same solar charge controller. It all depends on a whole range of factors. That’s why it is important to have an idea of what they are and do.
This article has different sections, all tackling relevant doubts homeowners have when looking for a home solar charge controller. You’ll also find a list of the best solar charge controllers in the market.
Table of Contents
10 Best Solar Charge Controllers
Let’s start by reviewing the best solar charge controllers in the market. This list provides you with a wide variety of controllers you should consider in your next purchase.
The EPEVER MPPT is an excellent controller for its price: it is quiet, efficient, and features high-quality material. Users highlight the controller’s high amp output and its high tracking efficiency. The controller has up to 99.5% high tracking efficiency and 98% peak conversion efficiency, maximizing the energy from solar panels to charge your system.
A versatile charge controller, the Outback Flexmax is a great addition to your power system. The controller can support a wide range of nominal battery voltages and step down a higher voltage solar array to recharge a lower voltage battery bank. Its backlit 80 character display shows the current operational status. You can also program the controller to charge battery voltages from 12 VDC to 60 VDC.
The MidNite Solar Classic 150 Charge Controller is MidNite Solar’s most popular model. Its maximum output current is 96 amps, and it can operate at a voltage of 150 volts. When it comes to batteries, the MidNite can support 12 to 72-volt battery systems. Users love MidNite’s Wi-Fi feature, enabling you to monitor your controller over your local network or the Internet.
One of the best in the market, the SmartSolar charge controller is as powerful as it gets. This controller can recharge a severely depleted battery since it can operate with a battery voltage as low as 0. The SmartSolar is an excellent choice if you live in areas prone to extreme temperatures. Thanks to its internal sensor, the controller can compensate for the environment’s temperature, guaranteeing your power output during summer and winter is nearly identical.
Renogy is a well-established manufacturer within the solar industry and the Renogy Wanderer 30A is one of the best PWM charge controllers on the market. It’s a very dependable and versatile controller, and it’s a suitable option for systems of 400 watts or less. The Renogy Wanderer is also compatible with multiple battery types, including SLD, GEL, and FLD.
The MOHOO 20A Charge Controller is one of the most affordable controllers in the market. It is ideal for charging small appliances such as lighting and small digital devices, like cellphones. The inbuilt extra USB ports are a huge plus most users appreciate. Unlike other controllers, the MOHOO is easy to set up and operate.
The Outback FM100 AFCI Charge Controller falls on the high end of the price range, at $1,005 as of this writing. Still, it’s worth the price. The safety features are the highlight of the Outback. The controller has a compact, outdoor-rated enclosure that keeps dust and moisture from damaging internal components. Aside from this, it also has an addition of arc and ground fault protection and rapid shutdown capacitor discharge. You’ll also find a programmable auxiliary control output for smart load controls
The Morningstar TriStar is a suitable option for larger systems. This controller works great and runs smoothly. It has 98% peak efficiency, with excellent performance at sunrise and other situations with low insulation levels. Its digital display meter shows amperes, wattage, and voltage, allowing users to monitor the controller’s functioning.
Arguably one of the most affordable Pulse Width Modulation controllers, the Allpowers comes with an industrial-grade STM 8 microprocessor to control the charger and discharge process. It can support 12v and 24v as well as multiple battery types. The controller features a useful display screen that shows battery voltage, battery level, and whether the battery is charging. It has extra buttons to scroll through other information like charging amps, load amps, the temperature of the controller, and optional settings.
The Rich Solar 20A Charge Controller has excellent value and standout performance. Its main highlight is the ability to automatically detect 12V or 24V DC system voltages. You won’t have trouble finding a suitable battery as this controller is compatible with various Deep Cycle battery options such as: Sealed, Gel, Flooded, and Lithium. The controller also features diverse load control and is even capable of charging over-discharged lithium batteries.
How to Choose a Solar Charge Controller
Time to move to the juicy part. Here you’ll find essential information about solar charge controllers to help you choose a suitable one.
What Kind of Weather Do You Experience?
Believe it or not, solar panels don’t perform their best under blazing sun. Instead, they work better when days are cool and semi-cloudy, but out in the full sun. As you might know, electrical appliances’ efficiency tends to decrease under hot weather, and your panels are no different. For example, a 100-watt panel will become an 83-watt panel at 110 degrees. In the solar industry, this decrease in efficiency is referred to as temperature coefficient, which describes how much power output your panel loses as the temperature rises above 77°F.
The temperature will also affect voltage. When photovoltaic cell temperature rises above 110 degrees, the voltage decreases, sometimes dropping below the input you need to fully charge the battery. When cells get cold, the voltage increases, thus increasing the input. Still, sometimes the array’s voltage gets increasingly higher than the battery voltage, posing a problem, too.
Both scenarios condition what solar charge controllers you should get to regulate temperature and voltage changes accordingly.
Voltage of Your Solar Panel and Battery
You’ll need to figure out the watts, volts, and amps of your solar array and batteries to choose the best solar charge controller for your setup.
Solar charge controllers aren’t always necessary; it all depends on the voltage of your solar panel. As a rule of thumb, you don’t have to install a charge controller with small systems or trickle charge panels, such as the 1 to 5-watt panels. In simple words, you don’t need one if the panel puts out about 2 watts or less for every 50 battery amp-hours.
However, if your panels put out higher numbers than these, you should include a solar charge controller to regulate the output and efficiency of your system. Most solar panels come with a voltage output of 12, 24, and 48 volts. Considering these values, you have to choose a solar charge controller that supports these voltages.
As for the batteries, the same principle applies. You need to know how many batteries you’ll be using, their voltage, and amp-hour capacities. Most batteries are 12-48VDC, and your solar charge controller needs to match them in output. All batteries show their amp-hour capacity in the instructional menu or datasheet.
You also need to know how much current your solar panels produce to ensure your controller can handle it. Here’s a simple formula to calculate how many amps you need in your solar charge controller.
- Solar panel wattage/battery bank voltage = amps requirement
What Do You Need to Run?
It’s essential to know what devices you want to run to figure out what solar charge controller you need. A solar system supplying power for large appliances like ACs and refrigerators will not need the same controller as a system that provides power for a small RV. Simply said, a solar charge controller must be able to support your power requirements.
A solar charge controller with an LVD (low voltage disconnect) output feature is a suitable option if you’re powering small appliances, like lights. Solar charge controllers with LVD automatically turn off the connected device when the load drains the battery bank to a low voltage. Thus protecting the batteries from reaching a depth of discharge that may damage them and reduce their lifespan. You can’t employ this system if your appliances are higher than 60 amps, though.
A PWM controller (or, Pulse Width Modulation) is an excellent option if you’re powering a remote system like RVs, vans, or slower power systems. PWM controllers are an affordable option and will efficiently and continuously power the system.
If you have larger systems, like grid solar panel systems, you’ll require an MPPT ( Maximum Power Point Tracking) controller. These controllers feature advanced technology that will ensure it collects maximum power from your array and then passes it to supply the battery, regardless of the voltage (we’ll get to that later.)
How Does a Solar Charge Controller Work?
A solar charge controller is a device that regulates and limits the power running from your solar panels to the battery. In other words, a solar charge controller allows the power that solar panels produce to go into the battery bank. Once the controller detects the batteries reach full charge, it suspends the charge the solar panels supply.
By regulating the flow of power, the controller ensures the batteries don’t overcharge, which can reduce the battery life and pose a safety risk. It also ensures the batteries do not drain at night when not in use.
What is an MPPT vs. PWM Charge Controller?
There are two main types of solar charge controllers: Maximum Power Point Tracking (MPPT) and Pulse Width Modulation (PWM). No controller is better than the other. Which one is right for you depends on your solar system’s needs.
Let’s explore the differences each controller has.
Maximum Power Point Tracking (MPPT)
MPPT controllers are more expensive and feature new technology that lets them operate at maximum power voltage. While MPPT controllers match the battery’s voltage, they will convert the excess input voltage to collect as much power as possible from the solar array. In simple terms, the controller will increase the current so that it outputs the same power that it is receiving from the solar panels. This function comes in handy in areas with extreme temperatures to regulate voltage.
Pulse Width Modulation (PWM)
PWM controllers are smaller and cheaper than MPPT controllers. They operate at battery voltage, which means that, once it is connected to the battery, the controller will match the voltage of the solar panels to the voltage of the battery bank. In other words, PWM controllers pull down the array’s voltage to that of the battery, resulting in PWM controllers charging your batteries at a slower pace.
Purchasing a charge controller for solar panels represents a large investment for homeowners, especially if you choose or need an MPPT model. It’s important that you consider what use you’ll give to the controller. So much information and considerations can easily overwhelm homeowners, making them choose a controller by simply looking at the price, whether that is cheap or expensive. Cheaper doesn’t mean bad, and expensive doesn’t mean better. The best solar charge controller is the one that suits your needs.
Also, remember that solar charge controllers are an essential component of your system and help protect another (also expensive) element: your batteries.