Choosing what to do with solar panels can be tricky - how long you want to be able to remain off-grid for, what your power consumption in your van will be, and whether or not you plan to spend time in campsites that have shore hookups will play a big part in what you decide to go for. As we plan to not use campsites very often but want to be able to power laptops, cameras and phones, we decided to install 3 100W solar panels. From our power consumption calculations we hope that we'll be able to spend 4-5 days in one place before depleting the batteries to 50%.
After a lot of research, we decided to buy the Renogy 100 watt, 12V solar panels as they get lots of good reviews - it's super easy to connect them together, and they use a simple mounting bracket which makes it easy to install them. We purchased the Z-Brackets, as well as a cable entry housing so we could route the cables inside while sealing against water ingress, and some solar branch connectors to connect all of the solar panels together.
Products, tools & consumables needed:
• 9 or 9.5mm drill bit
• Rubber grommet
attaching the brackets
After laying everything out on the roof so we could work out how to orientate the solar panels with enough room for the the skylight and vents, the first thing we needed to do was attach the mounting brackets to the solar panels.
As there weren't any Z-Brackets in stock on the Renogy website when we ordered our solar panels, we bought some Z-Brackets off Amazon that claimed they were for Renogy solar panels. We actually found that these didn't quite fit properly, and we ended up having to drill some of the holes bigger in order for them to attach to the solar panels properly.
Drilling holes in the van
Once the brackets were attached to the panels, we brought them back up onto the roof of the van and marked out where we would need to drill holes using the brackets as guides. Once we had marked all of the holes, we moved the panels to one side and drilled the holes.
Mounting the solar panels with wells nuts
As we know quite a few people who have had issues with water ingress, we decided not to use the self tapping screws provided with the brackets, as they are hard to seal consistently even with copious amounts of silicone sealant. Instead, we opted to buy some well nuts. These are constructed of a brass over-moulded nut surrounded by rubber. As the screw engages into the thread, the nut is drawn upwards expanding the rubber in and beneath the hole. This creates a seal around the hole, between the roof and the bracket, which will stop any water from being able to pass through the hole. In theory it is still possible for water to ingress around the head of the bolt and down the helix of the thread, so to reduce this risk we used a high shore hardness rubber washer to seal between the bracket and the head of the fastener.
We used M5 well nuts which suggest a hole size of 10mm, however this was far too big in our experience and it's easy for the head of the well nut to get pulled through the hole (this happened a few times and was super frustrating!). We drilled the remaining holes at 9.5mm and this was a much better fit. The ideal hole size for an M5 well nut would probably be somewhere between 9-9.5mm.
Wiring in the solar panels
Once the holes were drilled and the well nuts were in place, we screwed the solar panels into place. We then attached the solar panels to each other using the solar branch connectors, and fed them through the cable entry housing. We found it slightly confusing knowing what to do with the branch connector and the entry housing, as in order to be able to use the two together, you need to cut the ends off the branch connector.
We then attached the solar panels to each other using the solar branch connectors, and fed them through the cable entry housing. We found it slightly confusing knowing what to do with the branch connector and the entry housing, as in order to be able to use the two together, you need to cut the ends off the branch connector.
This wasn't a problem for us as we're not using a Renogy battery or charge controller, but it would be a bit of a faff to have to reattach the male/female connectors if you were using other Renogy products.
Sealing the holes
We then drilled a hole for the wires to feed through into the van and pressed a rubber grommet into the hole, to cover up the sharp edge of the hole and project the wires. Once we fed the wires through the hole, we then sealed the cable entry housing to the roof of the van using a combination of mastic tape and Sikaflex EBT.
The last job was to cover the solar panel fasteners with silicone sealant to make sure no water would have a chance of getting in.
For information on van conversion electrics, check out our camper van electrical system blog post!
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