Solar panels are an essential component of solar power systems, and they collect solar energy and store it in batteries. However, you cannot connect a solar panel directly to a battery and expect the battery to charge. That's where MPPT solar charge controllers come in.
MPPT stands for Maximum Power Point Tracking, and it refers to the voltage at which a solar panel produces the most power. The maximum power point voltage varies depending on environmental conditions and the time of day. MPPT charge controllers monitor the panel and determine the maximum power point voltage for the current conditions. This function maximizes the efficiency of a solar system by optimizing the voltage match between the solar panel array and the batteries.
Solar panels and batteries have different optimal operating voltages, and an MPPT charge controller is a DC-DC converter that regulates the charge current into the battery like a PWM controller. It also converts the voltage coming out of the panel to match what the battery needs. Without an MPPT charge controller, a lot of power gets wasted due to the voltage differential.
For instance, a 250-watt solar panel may have an optimal operating voltage of 32 volts under ideal conditions. However, as the panel heats up in the sun or on a hot day, the optimal voltage may drop to as low as 26 volts. The rated panel voltage must be higher than the battery voltage to accommodate these voltage drops in the panel and the increased required battery charging voltage.
Using the same 250-watt panel, the MPPT controller allows the panel to operate at the maximum power voltage (Vmp), which is the full rated 250 watts. The output from the controller to the battery still needs to match the battery at 12 volts, but the current increases to 20.8 amps, allowing you to utilize the full 250-watt potential of your panel.