MC4 Connectors not Novice-Proof

johnfconway

Tested a 30' section of line and another 10' section. Panel connectors were at 22.2V (not full sun today). 10' section mirrored that. 30' section only 8V... even after screwing with all 4 connectors multiple times.

Connectors purchased off Amazon. Tool that came with them fits the plastic nut. Renogy tool is slightly bigger than nut. That suggests no real manufacturing standardization among plants making these things. Decided to throw in the towel, buy Renogy connectors, snip wire ends and start all over.

Anyone else have mixed results with connectors?

DenisP

I had an issue with a MC4 connector on my 2018 400 with factory solar.  The contact was not fully seated in the MC4 connector.  I found the problem after using the 400 for 2.5 years and apparently was only getting the benefit of one of the 100 watt panels.  

ScottG

I use Renogy MC4s for a variety of temporary connections and have never had an issue with them. You do have to be careful to assemble them properly--both in terms of crimping and (as @DenisP implied) in making sure all the parts are properly seated when you snug them up.

johnfconway

@ScottG, "Renogy", I believe, is key word. When the other brand conductors were crimped and clicked into the housing, I noticed the depth of male and female conductors from lip of housing varied a lot. Possibly to the point where male and female conductors were not touching on one of the connections. The Renogy installed connectors on the solar panel and on the inline fuse have conductors uniformly close to lip of housing.

I ordered Renogy connectors. Will install them on that longer cable with all the precision I can muster and hope to see multi-meter dance to 22+V!

ChanW

I've found there's a subtle difference in quality with brands of MC-4 connectors, and that Renogy is better (note I've only compared to Windy Nation)... 

See this thread, about halfway down: 
https://tab-rv.vanillacommunity.com/discussion/7432