Why use a solar charge controller Solar charge controllers are included in most PV systems to protect the batteries from overcharge and excessive discharge (at night). The minimum function of the controller is to automatically assure the battery is fully charged and keep the battery fully charged without damage to the battery.

MPPT Controllers

Maximum Power Point Tracking controllers maximize the energy from the solar panels by optimally loading the solar panel based on the available sunlight.  This usually results in more current produced on the output side of the controller to the battery.


Controller Selection

The basic criteria for selecting a solar charge controller includes operating voltage (12/24/48 VDC) and the solar panels rated current (Amps). A solar charge controller should be able to handle the rated current of all the panels connected to it. Examples: A typical  135W solar panel (12V system) is rated at 7.4A. The MPPT controller will typically increase the current by 25%, therefore the MPPT controller selected should handle 9.25A ( 7.4 * 1.25 = 9.25A). Two 135W panels in parallel is 7.4A + 7.4A = 14.8A. For use with a MPPT increase this by 25%, or 14.8A * 1.25 = 18.5A. The MPPT controller must have a current rating equal to or greater than this value.

Desired Features. You may want to consider the following: Is an indicator required to indicate the solar panel and charge controller is working? Is an LED charging indicator sufficient or would you rather have a meter that displays battery voltage and charging current? Is conformal coating an important feature? Is Gel, AGM, or lead-acid battery selection important?

Below is a variety of available MPPT controller's.  Please select according to your needs and should you have any questions feel free to give us a call.