• Measure open circuit voltage (Voc) on a multimeter and compare it to the panel's listed Voc. If the reading is negative, reverse the probes and measure again. • If the voltage and current measurements are similar, the panel is in good condition. • If the voltage measurement is far off the listed Voc, it doesn't necessarily mean the panel is damaged or defective. • Measure short circuit current (Isc) on the panel's specs label. • Prep the multimeter to measure DC amps by moving the red probe to the amperage terminal and setting the multimeter to the amp setting (A). • If the multimeter's current rating is greater than the panel's short circuit current, use a clamp meter. • Place the panel outside in direct sunlight and use a towel to limit its output. • Touch the multimeter probes to the metal pin inside the positive and negative MC4 connectors. • Remove the towel and read the current on the multimeter. Adjust the tilt angle of the solar panel until you find the max current reading and compare it to the panel's Isc. • If the voltage and current measurements are similar to the panel's claimed Isc, the panel is in good working order.
