So, in part 1 we looked at calculating what system you needed. In part 2 we will look at how to install it and where to buy.
Firstly we will look at the panel. There are various opinions about which panel is best, ranging from the semi
flexible panels to the monocrystaline rigid panels. Certainly the flexi panels are easier to mount, lending themselves to being glued to the roof with a PU adhesive like Sikaflex. But, in order for the panel to be most efficient, it needs airflow around it to prevent overheating and being stuck to a metal roof, it lacks the airflow underneath and the reflected heat will cause losses through overheating. That said, in a simple system like that in a camper, the losses are low and even working at less than 100% it’s still adequate.
I elected for a rigid panel mounted on a roof rack. It’s attached by panel clips on the front edge and pop rivets through L section extrude aluminium and bolted into the roof rack. This keeps it very secure and of course allows the all important airflow. Also to get the best, make sure it’s clean. Even dust and shadows will reduce the efficiency of the panel. On the underside is a junction box and two cables. These cables need to pass through the roof, either by tucking under the pop top canvas or passing through a waterproof IP65 rated housing with cable glands. I filled the box with silicon and bonded it to the roof, so far it’s dry.
It’s worth noting that I added some solar panel connectors before the entry point into the roof to allow me to remove the panel if it was damaged without having to cut the wiring.
I used MC4 connectors which are waterproof, but they do vary in quality and despite having a recognised design, the connectors have differing clips which are not interchangeable. Finally use good quality multi-strand cable to minimise losses.
Once inside the van you need to have some way of controlling the power as the panels can generate more than 12v. Therefore it needs regulating and of course if you want to charge more than one battery, then it needs to distribute the power accordingly. Ours will take the solar power, charge the leisure batteries and also the starter battery. It allows you to decide how the power is split, in our case 50:50. It has indicator lights and a button that allows you change all the settings from battery type to charging split and frequency. It also houses an ambient air temperature sensor. Finally, although you can control it via the lights and buttons, there is also an option to fit a digital control panel which will show your volts, amp/hours, temperature etc. It connects via an Ethernet cable and can be positioned somewhere much easier to see.
As can be seen above, you can scrutinise every aspect of the system. It’s very self explanatory with the buttons allowing you to select the panel data or either battery and the system configuration. Finally there’s two lights: green = good, red = fault.
The final part is to connect it to the batteries and that is simply running cables via a fuse to the (+)ve and (-)ve terminals. And that’s it. Enjoy the free power of the sun. Don’t forget it doesn’t work in the dark or shadows or if it’s dirty. It works best if facing the sun directly so tilting it really helps – another advantage of the pop top.
Heres a few links to help – they are just examples and not necessarily the best.
When working with electricity, disconnect all the batteries.
If in doubt, consult an electrician