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Flexible Solar Panels and Polycarbonate on Sprinter Van Roof

After some very careful consideration, research, and late nights pondering the effectiveness and approach taken by other’s building their campervans, I’ve finally come to a conclusion as to how I plan to execute the install of my solar panels on my Sprinter van roof.

Basically, there are two types of panels, Rigid and Flexible. Rigid panels are glass panels with aluminium frames, and typically about 35mm thick. They are heavy, especially when building an array of rigid panels. The plus side is that they generally last longer, are more resilient to the elements, and produce better output overall.

Flexible panels on the other hand are extremely light as they’re typically only 3mm thick with solar cells mounted on a sheet of thin aluminium (resulting in that flex). Because the cells on flexible panels don’t use glass, but rather a type of thin membrane, they are more prone to damage by excessive heat, scratches and tears from tree branches, etc. They are also more expensive!

So why am I choosing flexible panels then? Well, the main reasons boils down to weight, safety, air resistance, and stealth. I’m growing increasingly concerned by weight in the van as I progress through the build. Keeping my solar panels as light as possible will aid in this regard. Secondly, the low-profile flexible panels will aid in reducing air resistance and also ensure the panels are not visible from street level (keeping things nice and stealthy). With regards to safety, I had explored the option of installing rigid panels on the roof using aluminium L brackets, but this seemed very risky to me. I read a lot about using 3M VHB tape, or SikaFlex to glue the L brackets to the roof ribs, but the weight of these rigid panels and brackets really gave me the hibbie jibbies. Just image for a minute the consequence of those glass/aluminium rigid panels flying off the roof at 110km per/hour straight into the the car behind me… Oh man, let me stop here before I get sick.

I am going with flexible, light weight panels on the roof, but still using 3M VHB tape to mount them down, with added SikaFlex to fill the gaps and reinforce it. This recipe will ensure a bond so strong that it’s equivalent to bolting the panels into the roof. On the point of bolting and screwing the panels, I’m avoiding this too because I don’t want to add any more holes in the van than what is absolutely necessary. So 3M VHB tape and SikaFlex will fuse the panels to the roof as if they were welded. Removing them in the future should be as easy as using a guitar string (probably the lower E), and with side-to-side motion, cut through the bonding material and slice off the panels.

Ok, so here’s my approach:

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I’ve purchased 2x 200w SunPower flexible solar panels on eBay. Both will be sandwiched on a sheet of 10mm thick ducted polycarbonate and edged sealed to close off the side gaps. Panels will be joined together using the polycarbonate joiners resulting in a single 400 watt solar array into a single unit. The panels I’ve purchased are slightly wider than the inner ridges of the roof (see above image), so the panel overhangs ever so slightly. I’m not too concerned by this, though I’d like to ensure the edges are fully mounted so to avoid any wind flapping (not sure that’s even a thing). I’ll probably use a spacer of some kind, perhaps another layer of the polycarbonate to raise it up. The polycarbonate has it’s own corrugation since this material is often used for housing and roofing applications to allow water to flow down the incline. I plan to angle the polycarbonate sheet so that the corrugation is perpendicular to the ribs of the roof. This will allow water that happens to get underneath the panels, and potentially into the corrugation of the polycarb, to flow towards the sides of the roof where the Sprinter van has stock canals for channeling water to the rear of the van.

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Corrugated Polycarbonate Sheeting

There are two (even 3) major benefits with this approach. First, the corrugated polycarb sheet creates an air gap underneath the flexible solar panels. Consider a 40 degree summers day in Australia. That roof is metal and can reach extreme temperatures in direct sunlight. With panels mounted flush to the roof, that’s a sure-fire way to reduce the lifespan of any flexible solar. So adding an air gap is a no-brainer really. Also, this particular polycarbonate sheet that I’m buying from Bunnings acts as a UV shield, so in direct sunlight, it should keep the van much cooler, theoretically shading the van in direct sunlight.

So that’s my execution plan for solar panels. Only time will tell really as all of the above is theoretical at this stage. Below I’ll list the products I’ve purchased below. These are all from Bunnings in Australia, but I’m sure you can find them at Home Depot or similar if you’re overseas.

If you are interested to learn more about my Sprinter Van Build Series, visit my personal blog at https://9th.Life

Written by

Hello, my name is Marco. I am a blogger living in Sydney. This is my blog, where I post stories about life and the things that entertain me. Thanks for visiting

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