I bought one of these to do what your asking about :
But at $109 its not that cheap and as mentioned a volt meter will do just fine to see if its working. The reason I bought the above linked meter was the mc4 hookups which makes it easy to test panels.
But at $109 its not that cheap and as mentioned a volt meter will do just fine to see if its working. The reason I bought the above linked meter was the mc4 hookups which makes it easy to test panels.