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.
Series connection → Voltage adds up, current stays the same.
Parallel connection → Current adds up, voltage stays the same.
Combiner Box → Joins multiple strings together before feeding them to the inverter.
Voc (Open Circuit Voltage) → Used to calculate maximum string length (must not exceed inverter max input).
Vmp (Voltage at Maximum Power) → Used to check if string operates efficiently within inverter’s MPPT range.
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.