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SOLAR CHARGE CONTROLLER
Solar Charge Controller is an electronic device that manages the power going into the battery bank from the solar array. It ensures that the deep cycle batteries are not overcharged during the day and that the power doesn’t run back to the solar panels overnight and drain the batteries. Some charge controllers are available with additional capabilities, like lighting and load control, but managing the power is its primary job.
A solar charge controller is available in two different technologies, PWM and MPPT. An MPPT charge controller is more expensive and highly efficient than a PWM charge controller, and it is often worth it to pay the extra money.
Key Features of a Solar Charge Controller
A PWM solar charge controller stands for “Pulse Width Modulation”. These operate by making a connection directly from the solar array to the battery bank. A 12V solar panel can charge a 12V battery. A 24V solar panel or a solar array is needed for a 24V battery bank, and 48V array is needed for 48V bank.
An MPPT solar charge controller stands for “Maximum Power Point Tracking”. It will measure the Vmp voltage of the panel and down-converts the PV voltage to the battery voltage. When the voltage is dropped to match the battery bank, the current is raised, with a 20V solar panel, you can charge a 12V battery bank.
If you try to charge a 12V battery with a 24V solar panel, you will be throwing over half of the panel’s power away. If you try to charge a 24V battery bank with a 12V solar panel, you will be throwing away 100% of the panel’s potential, and may actually drain the battery as well.
- Multistage charging of battery bank changes the amount of power set to the batteries based on its charge level, for healthier batteries.
- Reverse current protection stops the solar panels from draining the batteries at night when there is no power coming from the solar panels.
- Low voltage disconnect turns off the attached load when the battery is low and turns it back on when the battery is charged back up.
- Lighting control turns attached light on and off based on dusk and dawn. Many controllers are configurable, allowing settings for a few hours or all night, or somewhere in between.
- Display may show the voltage of battery bank, state of charge, amps coming in from solar panel.