What is a MPP?

The conditions that solar panels work under out in the real world are constantly changing, and as these conditions change the voltage and current produced by the solar panels constantly change as well. The power being produced by a solar panel is proportional to the current (I) and voltage (V) of the solar panel as can be seen on the graph to the right. This a typical IV curve of a 224W solar panel and as can be seen the spot on the curve which both the voltage and current are at their highest is the maximum power point, or MPP.

What is a MPPT?

To get the most power possible out of a solar panel or a bank of solar panels it is imperative that this maximum power point is constantly tracked by the solar inverter or charge controller as it is constantly changing. A solar inverter or charge controller that can track this maximum power point is called a MPPT which stands for Maximum Power Point Tracker. Most solar power inverters 3kW in size or larger have multiple MPPT’s so they can get the maximum power from solar panels which have different voltages or current, this may be from solar panels facing a different direction, banks of solar panels of a different amount or types amongst other things.

When solar panels are connected to a MPPT solar inverter they are usually connected in series, which means each solar panel is connected from positive of one panel to the negative of the next. When wired this way the voltage of each panel adds together but the current stays at that of one panel; so if 10 of the 224W panels shown in the graph above were wired in series the horizontal axis for current would stay the same but the vertical axis for voltage would be multiplied by the 10 panels, so the series string of panels would have a voltage of 400V. The worst thing about having solar panels wired in series is that every panel wired up together or stringed together like this is only ever as good as the weakest link.