How To Test Your Solar Panel Blanket

Before you start: 

The specifications of the solar panel being tested are the Open Circuit Voltage (VOC) and Short Circuit Current(ISC). Most of the time, these are detailed on the back of the solar panels.

SUNLIGHT!!!!! Testing solar panels either at night time or in poor sunlight conditions will give false and misleading results. For the best and most accurate performance indication, full, bright sunlight is required directly onto the panel.

Ensure the solar panel is disconnected from a regulator and battery.

Testing Open Circuit Voltage (VOC)

Have the panel disconnected from the regulator and the multimeter set to measure DC Voltage (this is usually shown as “V - - -” on the multimeter).

Connect the positive lead of the multimeter to the positive wire (or terminal) of the solar panel and the negative lead of the multimeter to the negative wire (or terminal) of the solar panel. The multimeter will now show the Open Circuit Voltage of the solar panel.

Results (typical)

12V nominal panel: 18 to 28V.

24V nominal panel: 34 to 56V.

Testing Short Circuit Current (ISC)

Have the panel disconnected from the regulator and the multimeter set to measure current (A) - ensure that a

A minimum setting of 10A is selected (Note: for panels with an ISC greater than 10A, a multimeter with a suitable current rating should be sourced).

Directly connect the positive lead of your multimeter to the positive wire (or terminal) of the solar panel and the negative lead of the multimeter to the negative wire (or terminal) of the solar panel. This will show the Short Circuit Current of the solar panel.