Step 1 Open Circuit Voltage Test

Mismatch/tolerance for power = 0 ~ 3V
- Pmax STC = 380 W
- Open circuit voltage at STC = 48.5 V
- βVoc_v =-0.1455V C⁻¹

Similar to Step 1 Choose PV Module
fmm v is power de-rate factor due to mismatch (decimal)
Take worst case.
Convert to decimal if need
- fmm v = [ ( Pmax STC - Power tolerance(W) ) / Pmax STC] / 100%
- fmm v = [ 100% - Power tolerance(%) ] / 100%

Power tolerance = +0 W

fmm v= [ ( 380-0 ) / 380 ] / 100% = 1

βVoc Temperature coefficient for open circuit voltage (% °C⁻¹ or % K⁻¹)

βVoc_v Temperature coefficient for open circuit voltage (V°C⁻¹ or VK⁻¹)

Voc STC Open circuit voltage of the PV module at STC (V)

βVoc = (-0.1455 VC⁻¹ / 48.5 V) *100% = - 0.3%C⁻¹

Voc string STC = Voc STC X Ns

Voc string STC String open circuit voltage of the PV module at STC (V)

Steps:

Checking the sticker on the cable of the solar panel is recommended. The sticker will label the positive or negative terminal.
- Generally, the positive terminal of the solar panel is connected to the MC4 male connector.
- The negative terminal of the solar panel is connected to the MC4 female connector.
Connect hardware (One module, Two module in series, Two module in parallel)
- The multimeter probe can be reversed, ignore the sign.
Multimeter change to DC voltage mode V⎓
Press Hold button on multimeter
- Voc string measured should be close to Voc string STC even ageing and low solar irradiance.

Different solar modules and instruments were used in these videos, so the reading is not same as assumption and calculation.

One module

One module.mp4

Two modules in series

Two modules in series.mp4

Two modules in parallel

Two modules in parallel.mp4

Criteria: >350 Wm⁻² only record

Steps:

Measure solar irradiance.mp4

Steps:

Press the thermometer
Point the red dot to PV module
- [Correction in video] The thermometer should be perpendicular to PV module.
Release the thermometer

Measure PV Module temperature.mp4