Solar Charge Controllers

A solar charge controller is an important part of power systems that moderates the level of energy entering and leaving your batteries. While the right charge controller will protect your batteries from overcharge and excessive discharge, any charge controller will ensure its base function: to maximize the lifetime of your energy storage.

Your perfect charge controller is closer than you think, but many options exist to suit your particular needs. Some base criteria for selecting a charge controller are as follows:

What is the operating solar PV voltage and the solar PV panels rated current?

A solar charge controller should be able to handle the rated current of all the panels combined.

Examples:

  • One 85W solar panel is rated at 5.02 amps. As a result, your selected controller should handle 5.02 amps.
  • Two 85W panels connected in parallel are rated at 5.02 amps + 5.02 amps. Knowing this, your selected controller should handle 10.04 amps.

What kind of mandatory/optional features do you want for your charge controller?

  • Is an indicator required to indicate the solar panel and charge controller is working?
  • Would an LED charging indicator be sufficient or would you rather have a meter that displays battery voltage and charging current?
  • Is conformal coating an important feature?
  • Is Gel, AGM, lead-acid, or lithium-ion battery selection important?
  • Do you need to be able to connect to your charge controller with your smartphone (or any other Bluetooth-enabled device)?

With so many options on the market, consider your preferences and requirements before purchasing!

Do you need an MPPT charge controller?

MPPT charge controllers maximize the efficiency of the power transfer from solar panels to the battery through use of Maximum Power Point Tracking (MPPT). An MPPT charge controller constantly seeks the maximum power point on your solar panel to transfer its energy.

Example:

  • Given a 17V output from a solar panel, an MPPT charge controller might reduce the voltage to only the 13V required to charge your battery. Furthermore, during conversion, the current increases from the solar PV panel up to a possible 25%.

Would a Diversion Load Controller be more suitable for your installation?

A Diversion Load Controller monitors your battery voltage and limits its maximum value by diverting some of that energy into loads.

When used in combination with solar PV panels, a diode is inserted between the solar panel and the battery bank eliminating discharge power in the evening. Most Diversion Load Controllers use a resistor to dissipate the excess energy in the form of heat, or, in some cases, the energy is placed into an onboard hot-water tank.

MPPT Charge Controllers

While charge controllers are often described as the brains of a solar system, MPPT charge controllers are even smarter. Powerful and efficient tools for harvesting renewable power, "Maximum Power Point Tracking" (MPPT) allows charge controllers to optimize incoming solar energy and convert that energy into the variable lower voltages required to charge batteries. This allows you to make the most of your solar system!

PWM Charge Controllers

PWM Solar Charge Controllers (often called series type controllers) provide a low-cost and excellent solution to regulating the harvested solar energy from the solar panels into the batteries. These controllers will allow for maximum charge current to be fed to the batteries without excessive amount preventing battery overcharging. Optimal performance is achieved when solar panel output voltage is approximately 20% above battery full charge voltage.

Class 1 Div 2 Solar Charge Controllers

Class 1 Division 2 Solar Charge Controllers are used for offshore and mining applications.

Diversion Load Controllers

Diversion load charge controllers are typically used with solar PV panels, wind generators and Hydro generator renewable energy products. They monitor the battery preventing it from overcharging by adding an additional load to the battery electronically. They require an external load, typically a resistive load bank, which dissipates the excess energy in the form of heat. Optional heating coils are available that can be installed in hot water heaters to dump the excess energy into the tank thereby heating the water.

If you need further assistance finding your perfect charge controller, feel free to contact us and any of our knowledgeable salespersons will be happy to assist you!

Explore Solar Charge Controllers