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The main function of a charge controller (also know as a charge regulator or battery regulator) is to safely charge a solar deep cycle battery at the correct charge rates, and to protect the battery from overcharge. We offer a wide selection of solar charge controllers for a variety of applications: solar lighting controllers, AC chargers and much more. Click below to learn more!

Do you have questions about what is the best charge controller for you? Give an altE solar expert a call today at 877-878-4060.

More Info on Charge Controllers

What Are Solar Charge Controllers And How Do They Work?

Find out the basics of a solar charge controller, what it does, how it works, and how to select the correct size for an off grid solar power system. A charge controller is an important component in a battery based solar system and are not used in straight grid tie systems.


  • Solar Charge Controllers are used to regulate and optimize the charge from solar panels, and to protect batteries in solar power systems.
  • Solar Lighting Controllers offer both a solar charge controller and a programmable lighting controller in one unit. DC lights or other DC loads can be run directly off of the solar lighting controller at scheduled times, potentially eliminating the need for a separate timer or load controller.
  • AC Battery Chargers use an alternating current (AC) source, like a wall outlet, to charge a Direct Current (DC) battery bank. Various models are available that allow for faster charging, or different voltage inputs and outputs.
  • Diversion (Dump) Load Controllers have the capability of being either a solar charge controller, a DC load controller, or a diversion load controller.
  • Temperature Sensors allow a charging source, such as a solar charge controller or AC charger, to know the battery temperature. This prompts the charging source to adjust the settings in order to provide appropriate charging as well as to protect the battery.

OutBack FLEXmax 100

In this video from Solar Power International 2017, we check in with OutBack Power and learn about their new higher voltage FLEXmax 100 MPPT controller. This is a highly flexible and configurable piece of solar componentry—it can set up to string 6 or 7 solar panels in series for a high-voltage, low-current run to the solar battery bank. This allows the use of smaller wire runs for less voltage drop. The FLEXmax 100 is NEMA3 rated which allows for installing outside near the solar array.

The FLEXmax 100 comes with integrated ground fault protection, and is compatible with both 24 volt and 48 volt battery banks. It allows for 100 amp output and can accommodate up to 5kW of charging to the battery bank.


People often ask us: How do charge controllers actually work, and what do they do in a solar power system? Or, why do I even need one in my solar system—can’t I just connect my solar panels directly to my batteries?

Charge Controllers are necessary because they protect your batteries from being overcharged by your solar panels, and they block any reverse current from the batteries to the panels at night. By extension, they protect every aspect of your solar power system.

Temperature sensors are an inexpensive addition, that help the charge controller more accurately regulate the charge of the battery bank.

The Low Voltage Disconnect (LVD) feature allows you to connect a DC load that is the same voltage as your battery bank, and allows the controller turn it off when the battery bank is low. This protects the batteries from being completely drained, also known as “deep discharging.”

Learn more about solar charge controllers, including MPPT vs. PWM controllers, over on our blog: “Solar Charge Controllers.”

Midnite Solar’s The Kid Solar Charge Controller

Want to learn more about an MPPT charge controller that is perfect for an off-grid solar system or marine application? Check out our video on “The Kid” from Midnite Solar. This controller is extremely versatile and can manage power from solar panels to a variety of deep cycle batteries—including AGM, gel, flooded lead acid, lithium, calcium and even custom batteries. Continuing with the theme of versatility, The Kid can be used in 12 volt, 24 volt and 48 volt systems.

The Kid also offers the option of stacking multiple kids together depending on the needs and type of solar system you are using. The Kid is simple to install and offers powerful customization abilities, so you can set it up to your specifications.

Troubleshooting a Solar Charge Controller

Check out our video on how to troubleshoot a controller. In this video we show you how to be sure your solar power system is properly charging the battery through the charge controller. Getting to know the equipment that makes up your solar energy system is a worthwhile endeavor—especially if your system is set up in a remote off-grid location.

We’ll show you how to measure the current going from the unit to the battery bank, using a multimeter set to read amps, to make sure your system is up and running. Multimeters are an important piece of equipment to have on hand to help diagnose problems with off-grid solar systems. Most multimeters are able to read both DC volts and DC amps, which will allow you to look beyond just measuring volts. Watch and learn more!