If your panels are used, it may be a good idea to carefully inspect the MC4 connectors or just replace them altogether. YOU can purchase an MC4 crimper on bezos for under $30 that works just fine. As for the connectors, the original are now made by Staubli. These are good quality. The pins, plastic and the o-rings that prevent water intrusion are good quality as well as the tabs that lock the male and female together. I have also used Renology and they were also satisfactory. I have used the generic el cheapos available online and if you get lucky, great, but you may not. Also, with the el cheapos, they may not make a good connection if not a matched pair.
Remember to buy at least 2 of the plastic MC4 spanner wrenches to connect and disconnect them and screw and unscrew them.
Whenever I connect MC4 together, I apply a dab of dielectric grease to the male and female. This helps reduce corrosion, allows for taking apart in the future and blocks water. Its good practice to do this.
NEVER WORK ON THE PANELS IN THE DAYTIME WITHOUT A METER TO MAKE 100% CERTAIN WHAT IS HOT AND WHAT IS NOT.
IF YOU ARE INEXPERIENCED, WORK AT NIGHT WITH A FLASHLIGHT OR LAMP. if you are making connections outside and are inexperienced, make some test connections on a piece of wire indoors first to practice with the tools and test your connections with a meter for continuity.
