In a solar PV system, stringing means connecting multiple solar panels together in series or parallel to form a "string" that matches the voltage and current requirements of the inverter.
Think of it like connecting batteries in a torchlight:
When you connect in series, voltages add up.
When you connect in parallel, currents add up.
Inverter compatibility: Every inverter has a minimum and maximum voltage window. The way you connect modules (stringing) must ensure the inverter works within this range.
Efficiency: Poor stringing can lead to mismatch losses and reduced energy generation.
Safety: Correct string sizing prevents over-voltage conditions (especially in cold weather when panel voltage rises).
String → A group of solar panels connected in series.
MPPT (Maximum Power Point Tracking) → A Built-in Technology, in some String and Hybrid inverters, to continuously optimize the electrical output of solar panels by dynamically adjusting the operating point to extract the maximum possible power, even under varying conditions like sunlight intensity, temperature, and shading. This technology ensures the solar power system operates at peak efficiency, increasing energy harvest and improving the overall performance and power output of the system
Voc @STC → Open
Circuit Voltage for the allotted panels in that string at the standard test
conditions of panel (assumed to be 25 deg C)
Voc @ (Min Temperature) → Open Circuit Voltage for the allotted panels in that string at the lowest possible temperature at the location
Vmp (Max Temperature) → Voltage
at Maximum Power for the allotted panels in that string at the highest possible
temperature at the location
Vmp @ STC → Voltage at Maximum Power for the allotted panels in that string at the standard test conditions of panel (assumed to be 25 deg C)
Say you have 400 W solar panels, each with:
Voc = 40 V
Vmp = 34 V
If your inverter has:
Max input = 600 V
MPPT range = 250 V – 500 V
You could connect 12 panels in series:
Voltage = 12 × 34 V = 408 V (within 250–500 V range ✅)
Voc = 12 × 40 V = 480 V (below 600 V max ✅)
That’s one string of 12 panels.
If you have 48 panels, you’d make 4 strings of 12 and connect them in parallel at the combiner box.