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We have an extended Chevy express with a 24" high-top, on which we intend to install roof-mounted PV.

I'm really concerned with how to properly install the panels. We've selected six 100 W Renogy panels and a 400 Ah LiFePO4 battery pack, but it might be too much for our roof. I'm worried that if we are going 80 mph up I-5 and hit a 40 mph cross-breeze we could tear the roof off the van, rip the panels off the roof, destabilizing and roll the vehicle, etc. How can I avoid or minimize these risks?

I was initially thinking of laying three panels long-ways on each side of the van, with a ~20" section down the middle I can walk down and hang out or service the panels, and where the roof vent will go. Each section then would only be 22" wide (140" long) with space on both sides for air to dissipate to either side.

My plan is to build my own rack with bent heavy conduit and bolts. The rack should be pretty strong. But could unwieldy pressures blow out the panels? I don't know what thresholds they should withstand. The product shows 2400 Pa high winds and 5400 snow, but what does that correlate to in driving down the road?

You'll notice that with the current layout, the panels must go over each side by 4.5 inches. To me, this means they can be more affected by wind. If the roof was just flat instead of the bubble top, mounting might be much easier.

Air
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Liandri
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4 Answers4

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I work for a company that, builds custom truck bodies and upfits vans, though we do not work with GM/Chevy vehicles.

Your best source of information will be in the Body Builder Guide that GM provides to upfitters and others that use their vehicles as a base for their own custom vehicles.

You'll also want to review GM's Best Practices (found at the same link).

In general, you'll want to tie in whatever structure you create to the structure of the van itself, following the Body Builder's Guide and the Best Practices. Deviate from those at your peril/liability.

I would not use metal conduit as a structural material. It's not intended for that kind of use.

DLS3141
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There are a few different issues here.

Firstly is the integrity of the frame itself. As well as the loads from the weight of the panels and aerodynamic drag it will be subject to fairly significant vibration and weather exposure over it's life so corrosion and fatigue are potential concerns.

The next thing is establishing decent mounting points to the vehicle. Ideally you want to be bolting into structural members in the body of the vehicle rather than just single skin panels, even if this involves fabricating brackets to link the rack mounting points to something solid. Also the top section of extra high roof vans are often fibreglass or moulded plastic so you may well need to add an internal frame to extend the load down to structurally rigid parts of the vehicle. If you are lucky you may find unused seat-belt mounting points (if the same body is used for a people-carrier) which can be used. Otherwise you may have to drill into a pillar and back it with a plate and captive nut.

The final consideration is aerodynamic forces. Here the main concern is to avoid generating lift by getting airflow underneath the panels. A simple spoiler to direct airflow over the top of the rack will help a lot here but ideally you would want to have the whole thing sealed all the way around and perhaps have it slightly higher at the back. If you can create a smooth blend between the panels and the roof of the van you should avoid any serious issues.

Chris Johns
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I mounted 20 solar panels to the roof of my Airstream, which has a curved roof. I did this using two L brackets, attached together, then one attached to the panel, through the pre-drilled hole. The other bracket is attached to the top of the trailer using VHB tape. I topped off the attachment to the trailer with eternabond tape. This works great, no drilling, and seems to be the current standard.

Good Lux
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I would suggest building a support structure on the interior under the roof to help root the panels as well as distribute any force from driving more evenly. to help prevent air pockets and high upward pressure i would angle the panels with the front part being on the downward slope. this will increase drag but you should not have to worry about the panels or roof ripping off. also consider cutting off the bubble top and welding a flat piece of metal.

connor67
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