Balancing Solar Strings
Most Solar Inverters require that every string must have the same number of modules and must be on the same plane.
Let's explore this.
For the most part, the Maximum Power Point Tracking algorithm on most inverters chooses the best voltage and the best amps to get P = E x I....or Power in Watts equals (E) voltage x (I) current.
If the strings aren't balanced (same number of modules per string), one string has a higher voltage than the other string. This results in the inverter trying to pick the best voltage and best amperage for the system. The result is that any extra modules (6 in a string vs. 7 in a string) tend to lose their value.
So, if you buy this, strings must be balanced.
Fronius has an excellent white paper devoted to balanced strings on different planes.
If you go into the field and test modules, you will find that their voltage tends to be very similar regardless of azimuth. The resulting conclusion, therefore, is that the voltage (constant) x current which the inverter can't distinguish = power. The Fronius white paper shows that modules can be placed on different planes, as long as the strings have the same number of modules per string.
