PolyString Design?

[Bendesa1962]

Hi Everybody,

I'm dealing with the following situation:

3000 Wp Hybrid System
Available roofspace

Facing East 6 panels 250 Wp tilt 22 degrees
Facing West 6 panels 250 Wp tilt 22 degrees

Inverter has just one MPPT

Anybody experience with PolyString?

So what I want to do is make two strings for each roof of 6 panels each in series. These two strings will be connected (Parallel) to the one MPPT of the inverter.

The info of the panels is:

12 x Canadian Solar 260 Wp

Voc 37,5 V
Vmp 30,4 V
Imp 8,56 A
Isc 9,12 A

Inverter Growatt 3000HY

maximum PV Input Power 4500 Watt
Maximum input current 18A
MPP Voltage Range 250 - 450 VDC
Startup Voltage 115 VDC

So what do you think?

Thanks for advice and tips

Regards

Johan

[sensij]

6 panels in a string will only give about 180 V under normal conditions. You could run into trouble with the system dropping out if you have partial shade, or if it gets very hot. You might want to consider microinverters, or maybe the Fronius Galvo series of string inverters, which are designed for small systems. Your idea putting one string east in parallel with the strong on the west is fine, if the voltage is not a problem.