Step-by-step Solar Panel Installation Guide

Installing a solar panel system is normally a simple, straightforward process that can be done by anyone with basic DIY skills. Unless your caravan, motorhome, boat or yacht has a complicated wiring system, or you do not feel confident in waterproofing any holes in the roof, you don't need to pay for a professional to do the work. If you would like to have a solar panel system professionally fitted, we can arrange for a fitter to do the work for you. If you would like details of our installation / fitting services, please click here. (scroll down to see our step-by-step guide)

There are three basic stages to installing solar panels:

  1. Fit the mounting brackets and cable gland(s)
  2. Install the charge controller and cabling
  3. Connect everything together, switch on and final fixing of panels

This step-by-step guide should make things a lot easier, but feel free to contact us if you have any questions. You can view all the images from this page in a single gallery by clicking here. (opens in a new window)

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Step 1: Fit the mounting brackets and panels

Firstly, decide where you want to install the panels and which type of brackets you are going to use. The easiest is to mount the panels flat on the roof or deck of your motorhome or boat; in this case, we installed two 30 watt panels onto a narrowboat using polyurethane corner brackets. Typically, polyurethane brackets are fixed to the roof using Sikaflex bonding agent, although we have decided to use a less permanent solution: 'No Nails 10kg Tape'. This will allow us to remove the brackets later if we decide to move the panels. The panels are normally fixed into the brackets using the self-tapping screws in the bonding kit, which means we need to drill a small hole in the bracket and the side of the panel. Again, we are doing things a little differently, simply laying the panels into the corner brackets, allowing the customer to put the panels away when the boat is unoccupied.

To save on cost, and because we are using two small 30W panels, we decided to bolt the two panels together to create one larger panel. We did this by simply drilling through the side of the aluminium frame and using a couple of standard bolts, plus two strips of aluminium to reinford the join. In this case, we are setting up a 24V system, so we need two 30W panels connected in series (positive to negative connections), hence we used the two panels, not one 60W panel.

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Once you know where you want the panels to go, mark out the position on the roof using a tape measure and a pencil or marker. The easiest way to do this is to mark out the outline of the panel(s), rather than worry about the size of the panel + brackets. When this is done, lay out the brackets. When you are completely satisfied with their position, you are ready to start bonding. As mentioned, we are using the No Nails tape because we don't want to create a permanent installation. Whenever you use a bonding agent, it is important to ensure that both surfaces are grease and dust free, so both the brackets and the roof need to be wiped down with the cleaning (primer) agents supplied or with a mild detergent solution and allowed to dry.

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If we were using the Sikaflex bonder, we would apply it to the underside of the brackets using a sealant gun from a hardware store, but as we are using adhesive tape, we simply cut strips and stuck them to the bottom of the brackets. Using your pre-drawn outline of the panels, carefully place the brackets in the correct position, trying to build in a few millimeters extra so that you have a little margin for error and can easily position the panels later. When using Sikaflex as your fixing agent, BE VERY CAREFUL at this stage, because once the agent has set, you CANNOT move them later - it might be a good idea to check that the panels fit before everything has cured completely. In the case of Sikaflex 252, it will be partially set within 15 minutes and tack-free in 40mins. Once the brackets are in place, lay the panels face down in their brackets.

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The cable gland is where the panel cable(s) pass through the roof or the deck and allow you to easily create a waterproof seal. Simple drill through the roof where you want the cable to enter and fix the gland over the hole, using a bonding agent, so that the hole is under the sloped side of the gland. To create a 100% waterproof seal, you can use the bonding agent or a standard silicone sealant.

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Step 2: Install the charge controller and cabling

Ideally, the charge controller should be within 5m of the panels and within a metre or two of the batteries. The basic rule of thumb is that the shorter the cable the better, as it will reduce any voltage losses and result in a more efficient system. Cables that are supplied with the panels are designed to reduce voltage loss to less than 2.5% over 5m. For longer lengths, or if you are combining more than panel into a single cable set, you should use our cable charts or ask us for advice. Cleversolar 2.5mm solar cable is generally ok for 5m lengths up to 135W (270W at 24V) and our 4mm cable for up to 200W (400W).

If you are setting up a 24V system, you will need to connect two panels in series, which can be done very easily by plugging a +ve lead from one panel into the -ve of the other; the pair is then connected to one 5m cable set using the two remaining connections. If only connecting one panel or using the 'double clip' adpater to combine two panels into one cable set, then your cable gland needs only to have one entry.

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When you know where the charge controller is going to be, it is fitted using a couple of small screws or, in some cases, left free-standing. When in place, feed the solar panel cable to where the controller is and strip 1-2 inches of the end and strip 10mm from the internal cable to show the copper core (this should be twisted) - DO NOT connect the panels to the controller at this stage. Next, feed a correctly sized cable from the battery(ies) to the controller. Some people choose to install a fuse to the -ve cable or a blocking diode to prevent overnight discharge, but with most modern controllers, this is not entirely necessary. If you are connecting to a battery bank, or have a second charging source such as a charger/inverter, the controller is usually connected to the same battery terminals.

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Step 3: Switch on and fix solar panels

At this stage, you can connect the charge controller to the batteries. If possible, always use fully charged batteries for the first install. Once connected, the charge controller will go through it's start up process; when this is finished and if the status indicators do not show a problem, you can connect the solar panel(s). If you didn't lay the panels face down earlier, make sure the panels are face down or covered so that they are not exposed to the sun and are not producing a voltage. Connect the solar panels to the charge controller and turn them face up or uncover them. The charge controller may go through a test phase now and then show a green status indicator. Assuming everything is good, you can now connect the internal 12/24V wiring system or other devices to the controller's regulated load output. NEVER connect an inverter to a charge controller! The controller's load output is limited by its current rating (A) and inverters often draw very high currents (e.g. 5-amps drawn on the 240V side becomes 100A at the 12V side).

Once you are happy with how everything is working, you should now fix the panels in place on their brackets. As mentioned earlier, this is normally done using the self-tapping screws supplied in the bonding kit or bracket set, so you only need to drill 2-3mm holes through the side of the metal frame of the panel. If using aluminium panel mounting frames, the frame should be supplied with 6mm zinc coated nuts and bolts for attaching the panel using the pre-drilled mounting holes on the underside of the panel's aluminium frame. Some people choose to use Sikaflex to fit the panels into their frames, which is a permanent solution, with the added benefit that the panels are very difficult (almost impossible) to remove and steal.

So, there we have it... your solar panel system is installed, set up and running, so you are now producing electricity from the sun! Of course, there are many variations on this theme, but installing solar panels really is easy.

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