What is MPPT and how does it work?

MPPT, or – Maximum Power Point Tracking – relates to the solar cell itself.  Each solar cell has a point at which the current (I) and voltage (V) output from the cell result in the maximum power output.  In the diagram below the curve is an example of the standard output expected from a solar cell, the Maximum Power Point is at the position marked on the diagram.


The principle is that if the output from the cell can be regulated to the voltage and current levels needed to achieve a power output at this point, then the power generated by the solar cell will be used most efficiently.

How is this done? 

A Maximum Power Point Tracking solar regulator will simulate the load required by the solar panel to achieve the maximum power from the cell.  The regulator will work out at which point the cell will output the maximum power and derive from this the voltage and current outputs required for maximum power to be achieved.  It will then calculate the load that it must simulate based on these voltage and current levels R=V/I.  The regulator, now receiving the maximum amount of power in, will then regulate the output according to what it is designed for.

So in layman’s terms, how does MPPT benefit you?

MPPT ensures that you get the most power possible from your solar panels at any point in time. It is particularly effective during low light level conditions.

These calculations result in an output that delivers maximum current at the required voltage at any point in time.  During low light level situations it will compensate for the low light level and find the new point at which the solar cell delivers its maximum power output.