# Solar panel connectors......



## TnAndy (Sep 15, 2005)

In the "for what it's worth" column:

I've been a whole lot less than impressed with the connectors that come on solar panels. My 2007 model panels came with MC-3 connectors, and the later ones with MC-4 connectors.....which are "locking" connectors where the -3 type were not. Great for "plug and play"......not so much for longevity to corrosion.

I have two arrays of 10 x 175watt panels, (5 strings of 2), each on it's own 60 amp Outback controller. In watching the displays on the controllers, I'd often find one array running 250-300 watts less than the other.....about the sum of two panels, or one string. I'd go up with a clamp on amp meter, and find the offending pair, wiggle the connector around, and get it to producing again.....for a while....

SO, finally I got PO'ed enough to cut most of them off.....all the MC-3's, and some of the MC-4's.











What I went back with was a crimp on connector, which I then soldered as well, and covered with heat shrink tubing and electrical tape.

NOW, both arrays are running within a few watts of each other, and, a bonus, upped the total output on each about 40-50w......my guess is because I cut out lousy connections, AND where the pairs are strung together, I reduced the 8' of bundled up wire to about 20", cutting out 30-40' of wire in the array, reducing voltage drop some.

Also, in the future, I won't be spending a dime on overpriced extension cables with pre-made connectors......I'll order a roll of the same cable, cut the connectors off the panel leads, and go from there !

I bet it's hard to say how many wasted watts are going on around the world due to the connectors.


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## mike554 (Jun 9, 2012)

I was getting ready to order mc-4 connectors and a pair of crimpers but now you have me thinking otherwise. I wonder why they don't just put a junction box on the back of the panels that you can hook into.


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## mike554 (Jun 9, 2012)

I used to be a marine mechanic a while back and we always put grease in crimp on connectors before crimping them to ward off corrosion.


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## Jim-mi (May 15, 2002)

Shame on you Andy . . The manufacturer always knows whats best for us...........

We all know that those mc connectors are the absolute end all . . . . . . . . . . LOL

insult to injury is that cutting the connectors off will void the warranty...........

I read on the dealer / installer list I am on, about many of the guys who are more than a bit less than satisfied with the mc's . . .and the very pricy crimper tools.


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## TnAndy (Sep 15, 2005)

mike554 said:


> I was getting ready to order mc-4 connectors and a pair of crimpers but now you have me thinking otherwise. I wonder why they don't just put a junction box on the back of the panels that you can hook into.


That IS how older panels were set up....then they went to the "plug and play" deal with a set of 4' leads on the back of each panel, running into a junction box where they are soldered.

And this isn't the only time I've seen connections causing a problem. 

Was up at a business one day where the guy had a grid tie only system a company had installed consisting of two strings of 12 panels, each connected to an inverter of it's own. One inverter wasn't working, and I told the guy "check the connectors". In that case, again, it was a bad connection on one string, which kills the output of the WHOLE string to the point the inverter wasn't getting enough voltage to fire up.

Jim:

Yeah, I've heard it voids the warranty....but hey, I'll take a working system over a 'warranty' any day !


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## nadja (May 22, 2011)

Andy, when I got my two 190 watt panels early this summer, they two came with the m-4 connectors. I cut them off, stripped the wire and wire nutted and taped them first thing. They are right where they are supposed to be on the old Fluke meter. They are ugly, and pricy at best.


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## Jim-mi (May 15, 2002)

Those mc connectors are strickly a $$$ thing to bring the price of a panel down.....
And of course the manos did a sell job on "It simplifys things" . . . . .It sure does . .at the customers expense as TnAndy found out....


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