DIY MC-4 Connectors- 2nd Photo Added

[BFL13]

I suppose everyone knows about these except me until today, but in case anybody does not, here it is.

There is a Male and Female version, so you need one of each to join your wires to the panel pigtails. Beware the metal pins!!! They are also male and female. No second chances if you screw up! The whole thing is an IQ test, like a Chinese puzzle, so be careful.

Before I learned about these, I was cutting off the MC-4s on the pigtails and connecting the pigtail wires to my #8 wires using various ways such as with wire nuts all taped up. Not very good! With these little things, you crimp the #8 you have to the proper pin and fit it all together, and now you can connect to the panel no fuss no muss!

http://www.wegosolar.com/products.php?product=MC%252dMALE-MC%252d4-Male-Clip-with-Pin

[BFL13]

Added second photo to above post showing a different panel MC-4

[beemerphile1]

BFL13 wrote:
I suppose everyone knows about these except me until today, but in case anybody does not, here it is...

http://www.wegosolar.com/products.php?product=MC%252dMALE-MC%252d4-Male-Clip-with-Pin

I hope you didn't pay that amount. I bought five pairs of the Renogy brand on Amazon for $10.

[BFL13]

Here you can sort of see the little spreaders on the pin that go in past a catcher inside the housing. Once past that catcher ring, you can't pull it back out, because of the spreaders (whatever they are called)

The white piece is to keep the end from squeezing in too much when you screw on the end piece.

Also shown is an actual MC-4 on a cut-off pigtail from a previous panel I did. It is all glued together so there is nothing to undo. You can use the cut off one but would need to wire nut or somehow otherwise connect the wire to another wire.

First step is to mark the positive panel pigtail near its MC-4 with red tape. Once the panel is lying down, you might not be able to tell which is which of the pigtails sticking out.

EDIT--OOPS! The new panel has different MC-4s on its pigtails, that do unscrew. (I didn't unscrew them all the way to see inside.)

[landyacht318]

steveh27 wrote:
I use SAE connectors.

I went this route around 12 years ago, getting many with 10AWg and 18AWG leads. The awg should be in quotes as 10AWg is actually closer to 12AWG.

I had a pair on my 25 amp 'smart' charger and they would get so hot passing this much current for a half hour I could smell hot plastic.

This just got worse with time, as the barrels would open up and one would have to tweak the connection to get contact.

I also hated how one could unintentionally reverse the polarity so one had to label input' and 'output'.

All my 12v SAE connectors and their pigtail are now in a plastic bag to be given away, and have been replaced with Anderson Powerpoles which are largely trouble free, but hardly perect.

[2oldman]

BFL13 wrote:
--Some panels have sealed junction boxes so you can't open them up to put your own wire in.

In that case I cut the pigtails to a few inches and glue on my own terminal block.

[bpounds]

BFL13 wrote:

bpounds wrote:
I guess I was more ignorant than intrepid. I dug right in and made all my cables. Soldered all the pins. Amazon has all these connectors too.

Are you supposed to solder the wire end and pin end after crimping with the fold over tabs and squeezing them?

--Some panels have sealed junction boxes so you can't open them up to put your own wire in.

Soldering is not required, and probably would not be if you purchased madeup cables. Which makes homade better IMO.

Also, I don't believe those you linked cannot be disassembled. It just takes a certain tool to do it. You are right that it is easy to get pins in the wrong body.

[BFL13]

MEXICOWANDERER wrote:
How many inches of pigtail do these panels provide?

About 39 inches. Go to the right for drawing of the panel I just got. Same for the 255w panel I got a few months ago. The good thing with that is they can stick out from under the panel after you lay it down, so you can do your wiring hook ups after.

http://www.wegosolar.com/products.php?product=DH%252d60P%252d275-Solar-Panel-275W-Poly

Side note--panel efficiencies are improving. Guy said they have a new way to cut the silicone so there is less waste and the cells fit together better so the panel can be the same area with more watts---If I got that right. This 275 at 17.8% is very close to the same size as the older 255 at 15.5%. I suppose that matters if you are doing a big array.

[MEXICOWANDERER]

How many inches of pigtail do these panels provide?

[BFL13]

bpounds wrote:
I guess I was more ignorant than intrepid. I dug right in and made all my cables. Soldered all the pins. Amazon has all these connectors too.

Are you supposed to solder the wire end and pin end after crimping with the fold over tabs and squeezing them?

--Some panels have sealed junction boxes so you can't open them up to put your own wire in.

[2oldman]

I go into the junction box and use the screw connectors.

[steveh27]

I use SAE connectors.

[BFL13]

The ones in the link, when assembled, cannot be undone. (so the guy explained---I have not done one yet.) No second chances if you get the sexes wrong with the metal pins and the outside parts. Too easy to mix up the metal pins which will fit either, but only work with one. It is the metal pin that fits into the other metal pin inside the housing (also sexed)

If you have some MC-4s with some wire sticking out, AFAIK it is the same thing. All you can do is use the wire to attach it all to another wire. (wire nut and tape?)

I knew about wires with MC-4s already on them, useless to me. I have seen on here about cutting the wire in half, but wrong lengths for my use. These DIY ones solve all that.

These DIY things are a "game-changer" for me.

[landyacht318]

Wire Nuts and tape?

for shame bfl....for shame
😉

My portable panels I am using 45 amp anderson powerpoles, as I use these everywhere else. Have to destrand 8AWG to 10awg thickness and shave the insulation square to get them to fit the housings.

I've started my engine through a pair of these in parallel.

I've kept all the MC4's I've cut off leaving a pigtail, will use them when I need a weatherproof, less temporary connection.

[bpounds]

I guess I was more ignorant than intrepid. I dug right in and made all my cables. Soldered all the pins. Amazon has all these connectors too.