How do you add modules to expand an existing system?
When expanding the size of a solar
array does it matter if you add panels that are or a different wattage and or brand?
Comments
The voltage (Vmp, Voc) and the current (Imp, Isc) matters more than the wattage or the brand.
It is not recommended to connect dissimilar modules in the same array, because either the voltage or the current might reduce. If you are using different modules, try to pick the ones with similar voltage and current.
An example;
Module A: 26 V, 7.2 A
Module B: 26 V, 5.2 A
Module C: 22 V, 7.2 A
Wired in Series:
A & B in series: 52 V, ~5.4 A (voltage adds up, current closer to the lower one)
A & C in series: 48 V, 7.2 A (voltage adds up, current same)
Wired in Parallel;
A & B in parallel: 26 V, 12.4 A (voltage same, current adds up)
A & C in parallel: 24 V, 12.4 A (voltage will average, current adds up)
Comments
The voltage (Vmp, Voc) and the current (Imp, Isc) matters more than the wattage or the brand.
It is not recommended to connect dissimilar modules in the same array, because either the voltage or the current might reduce. If you are using different modules, try to pick the ones with similar voltage and current.
An example;
Module A: 26 V, 7.2 A
Module B: 26 V, 5.2 A
Module C: 22 V, 7.2 A
Wired in Series:
A & B in series: 52 V, ~5.4 A (voltage adds up, current closer to the lower one)
A & C in series: 48 V, 7.2 A (voltage adds up, current same)
Wired in Parallel;
A & B in parallel: 26 V, 12.4 A (voltage same, current adds up)
A & C in parallel: 24 V, 12.4 A (voltage will average, current adds up)
What about all 3 in series?
Again, my assumption is that the voltage is going to add up, the current will be close to the lowest Impp (slightly higher) in the string.
As follows:
Vmp (string): 26+26+22 = 74 V
Imp (string) : ~5.4 Amp