solar subheading
Your shiny new solar panels have just been delivered – you can’t wait to get them on the roof of your van and start generating your own renewable energy. Off-grid adventures, here we come! But what’s this weird plastic part on the end of the cable, and what do I need to do with it?
These are MC4 connectors; you’ll need to learn to use them if you want to add a solar array to your campervan. If you want to avoid the hassle of sourcing all these components on your own, you can buy a solar system that comes complete with all the cable and MC4 connectors you could ever ask for.
We’ll unpack everything you need to know about MC4 connectors in this guide, ensuring you’re well-equipped to get your solar array up and running. If you want to take the easy, albeit more expensive option, you can skip the MC4 connectors by opting for Victron’s pre-terminated solar cable.
MC stands for Multi-Contact (the company which first came up with the idea) and the 4 represents the 4mm diameter used to make the electrical connection.
The connectors are IP67 rated, which means they have ingress protection against water and particulate matter. In non-sciencey speak, they are completely water and dustproof, so you can rest easy knowing they are perfectly at home on the roof of your campervan in a wild Scottish winter.
They are even rated at -40°C and +90°C, so it’s doubtful that these connections will bother you once installed. They are the industry standard for connecting solar panels and are now used worldwide, connecting solar arrays of all sizes, from your campervan roof to entire fields of solar panels.
When you buy MC4 connectors, they will arrive as a pair with a male and female connector. Don’t connect these until your solar panels are on the roof and you’re sure of how to connect them.
Your solar panels will come delivered with 2 short lengths of cable per panel.
Confusingly, unlike the rest of our system, which uses red cable for positive and black for negative, solar panels like to switch things up and use black for both. The good news is that they will be clearly labelled, so don’t panic.
Each of these cables should come with an MC4 connector already attached, one male and one female. What you will have to do, trusty van-builder, is attach the opposite MC4 connector to the cables which will run from your solar panels to your solar charge controller.
Before we go any further, don’t push any of the connectors together until you’re sure of how your panels will be connected, and definitely don’t do it before the panels are on your van!
If like me, you like to make mistakes, you may have already done this. If this applies to you, scroll down to the bottom for tips on disconnecting MC4 connectors.
How you connect your MC4 connectors to the rest of your system will depend on your solar array. That’s a topic for a different day but if you have any questions on this, then feel free to get in touch.
For now, we’re going to assume you have either one solar panel or multiple panels connected in series, as these scenarios are both most likely and can be installed in the same way. Note, we’ve coloured our solar cable just to make everything more visual.
Your MC4 connectors are made up of a plastic housing which provides water ingress protection and a metal terminal which makes the electrical connection.
The plastic body will come as one piece, but it can be broken down and threaded onto your cables in the correct order.
The male MC4 terminal is crimped onto the cable and then covered by the female MC4 body.
The female MC4 terminal is crimped onto the cable and then covered by the male MC4 body.
This is somewhat counterintuitive so before you crimp anything, make sure you’ve identified your male and female terminals.
If you’ve made a mistake and attached your MC4 connectors incorrectly, don’t panic – it happens!
If you’ve attached the connectors to your cable properly but just pushed a male into the wrong female then all you’ll need is a nifty little tool like this one from Renogy. These tools make quick work of the connectors and pull them apart easily.
If, however, you’ve crimped the female or male terminals onto the wrong cable, then you’ll need new MC4 connectors. Luckily, these are only a couple of pounds each so in the grand scheme of converting a van this is very much an okay mistake to make!
The part that has been crimped onto your cable is, unfortunately, unable to be removed, so your best bet is to sacrifice the end of the cable and start again with new connectors, just make sure you read the guide thoroughly before crimping this time! If you need some extra solar cable to accommodate this, it’s available here.
You should now have your MC4 connectors attached to your lengths of cable from your MPPT and have a male and female MC4 connector. Once you’ve installed your solar panels onto your roof, you can go ahead and press the MC4 connectors together, making your electrical connections.
If you have a single solar panel, simply connect the solar panel MC4 connectors to your newly installed ones. If you have multiple panels in series, connect the positive of one panel to the negative of the other, and then install your cable length as if they were a single panel.
Congratulations! You’ve taken yet another step in installing your solar panels and another step towards your dream of driving off into the energy-providing sunset.
So by now you hopefully have everything you need to install your MC4 connectors safely and securely.
The main thing to remember is that the female body and male copper terminal are a pair. Then the male body and female copper terminal is the other pair.
Once you’ve got this all you need to do is connect them to your solar cable and plug them in!
Good luck and happy building.
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