Klein CL390 Tools Voltage Tester on Used Solar Panel

Solar Education

Klein CL390 Tools Voltage Tester on Used Solar Panel

I did a voltage and current test using the Klein CL390 on this used solar panel that I bought off of someone selling a bulk of 10+ year old 190w panels on FB Marketplace.

I used the Klein Tools CL390 AC/DC Clamp Meter in order to test the open-circuit voltage and the short circuit amps of this solar panel. The original open circuit voltage for the solar panel was 32.8 Volts. I have been measuring the open-circuit voltage for this panel at around 27-29 volts as of late. 

The current has been measuring using the Klein CL390, between 5-6 amps on a regular sunny California day. The original short circuit current was measured at 8.05 amps. 

After doing some quick math, I calculated that there was a degraded voltage drop of about 13% over the last 10 years. 

This solar panel still produces energy and does work even though it has a lot of damage on it from various factors such as sun intensity and voltage and current loads over the years. 

I wouldn’t recommend for someone to go out and buy a used panel such as this one in order to use it on an off grid home solar system with battery backup. I’m mainly going to be using this to do some tests and learn more about how much a used panel performs over the years.