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TAKE THE LEAP

  • Writer's pictureThe Desert Cruisers

Step-by-Step Guide: Making MC4 Connectors for Your DIY Camper Solar Panels

Updated: May 27


Making MC4 Connectors
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It's time to finally install the solar entry glands and Starlink entry gland, which means we need to make our MC4 connections! We will have two solar entry glands, one for our 480W solar panels and one for our 175W solar panels. They will also be on two separate solar controllers which we will go over in our Electrical Overview. For this blog, we will simply focus on the installation of the MC4 Connectors and how we connect our solar panel array in series.


Parts And Tools Needed

parts and tools for MC4 Connector Install

Explorist Life Solar Wiring Kit 10 guage

SEAVIEW Retrofit Cable Gland For Starlink

Goggles

Step Bit

Braided Wire Loom


Setting Up the Holes for Solar Panel Wires

Since we have two solar arrays, we are going to have two solar glands and one Seaview Retrofit Cable Gland for the starlink cable.

 two solar glands

We found our location that we wanted the solar wires and the starlink wire to come through and measured thoroughly inside and outside of the box. We used our Dewalt Drill and a Step Bit to help cut through the aluminum roof and wore some protective goggles. We wanted to drill from the inside of our box because we knew exactly where we wanted it to be.

Hole Locations for Solar Wires DIY Build

We were happy with the locations and drilled the rest of the holes on the roof and inserted 3/4 inch grommets.


How To Crimp MC4 Connectors

Now that we are all done on the roof, drilling our holes and figuring out where everything is going, we need to piece together the wire that is coming from our solar controllers up to our roof to our solar panels!


On the two solar controllers, one is going to have our 480 Watt solar panels and the second solar controller is going to have our smaller 175 Watts solar panels.

480 W Solar Panel and 175W

Understanding MC4 Male & Female Connectors

On most solar panels, the positive wire has a male MC4 connector and then on the negative side of the solar panel is a female MC4 connector.


Where it gets tricky is when you are doing the MC4 connector connection. On our solar panel we have a positive male MC4 connector which means our positive wire coming from our solar controller is going to have a female MC4 connector that we need to install and crimp.


Since the negative side of the solar panel has a female MC4 connector, the negative wire coming from our solar controller will have a male MC4 connector.


Understanding the Pins to Crimp

Now the tricky thing to remember is the female MC4 connectors takes a male pin. The male MC4 connector has a female pin.


How to tell the difference between the pins? If you look at the diameters of both pins, the male is slightly smaller, narrower in circumference, then the male is able to fit into the female MC4 connector.

MC4 Connector Pins How to Tell The Difference

Crimping Your Positive Wire

First thing we are going to do is grab your positive wire. We are going to be installing the female MC4 connector with our male copper pin.


Get your wire stripper ready. Line up the wire to the pin itself, see how much you need to strip back, then use the wire stripper.


Now that the wire is stripped, take the male copper pin. Remember, the male copper pin is smaller in circumference. You can see there are little wings on the pin. That’s what is getting crimped. You want those wings facing upwards on your MC4 crimper.

How To Crimp MC4 Connector Pins

Insert your wings facing upwards in the crimper, then grab your wire and slide it in, crimp it down and check to see how snug it is. Also make sure than when you slide in your wires make sure nothing is out of the pin or exposed. If any wire are exposed, then you've stripped too much wire. Give it a good squeeze and thats it. You've crimped your first wire!

MC4 Connector Pin

You’re going to take your female MC4 Connector, unthread the end, slide the butt end you just unthreaded over the wire first, then on the second piece of the connector, you’ll see the blue weather seal in there, and slide the male end pin into the female MC4 connector and now it clipped into place.

Once it clips into place, tighten the end cap and thread it back on. And there you go, that is your positive wire, with the female MC4 connector and male copper pin inside. That is going to be going from our solar controller up through the roof to our solar panels.


Crimping Your Negative Wire

Now it’s time to the negative wire. We’re putting a MC4 connector on the negative wire which requires a female copper pin which has the larger diameter. Strip the wire, make sure the wings are facing upward over the wire and crimp it down. Give it good pull to make sure it’s not going anywhere. Now take the Male MC4 Connector, unthread the bottom and put it over the wire, grab the top of your MC4 connector, slide the pin through the weather seal and it should click in. Tighten the rear cap and that connection is done! Same process as before!

MC4 Female & Male Connector

Running Our Wire Through Entry Glands and Grommets

After this set, we went on the roof to run our open ends of the wires through our solar glands and through the roof leaving just our MC4 Connectors up there so that we can figure out the lengths to our solar controllers! Make sure you put the tightening caps on before you feed your wires through the solar gland because you will not be able to get them over your MC4 connectors.

Running Solar Wire

Creating a Series Connection with Our 480W Solar Panels

Positive wire coming from the rear 480W solar panel with the male MC4 connector will plug into the positive with a female MC4 connector that’s going through the solar gland that will go to our solar controller.


The negative wire from from the rear 480W solar panel with a female MC4 connector will connect to the positive male MC4 connector of the front 480W panel which creates the Series Connection.


The negative coming out of the solar gland with the Male MC4 Connector is getting plugged into the front 480W to the negative wire with a female MC4 Connector.


This same method applies to our 175W solar panels.


Securing the Solar Glands

We bought half inch VHB tape for part of the solar gland install and then we put some weight on top of the solar gland to help it adhere to it. Once that’s done, we will put Dicor Lap Sealant over the corners. We also scuffed around where the VHB tape would go to and wiped with rubbing alcohol so there would be some texture and a clean surface for the VHB to adhere to it.

Gluing Solar Glands

For those who are concerned about the longevity of using this method to secure our solar glands, it has been almost two years and has never fallen apart. You can also opt in to bolt or screw them in, but they are so light that we didn't find it necessary.


For our starlink cable, we purchased a Seaview Retrofit Cable Gland.

Solar Glands

Now it's time to seal the area with Dicor Lap Sealant. To help prevent a mess, we used blue painter's tape around our glands.

Now you have officially put together your solar wire connections on the roof! All the wires are in braided wire loom on the inside, and we also labeled the wires so we know which array is the 480W and the 175W solar panels. Because you're done with this, I'm sure you're all exicted to finish up the shiplap ceiling project, and that wraps up our MC4 Connectors and solar panel install.


Watch the Video Install!



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From 2020 to 2023, we embraced life on the road in our DIY sprinter van, The Desert Cruiser. With no prior building experience, we transformed our van into a home, exploring deserts and rainforests, seeking the best campsites, mountain biking, and living our dream. In June 2022, a new dream emerged — building a 2022 Ford F550 into our DIY Earthroamer. With hopes of future family adventures, we found our dream truck in Texas. We believe anything is possible and aim to inspire others to explore life to the fullest!

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