Larger solar panels on a van

Hello! I’m hoping I can find some help with using larger sized solar panels for my van build. I have already started buying/ordering stuff for my van, which will be a 2019 promaster 159” WB extended. I haven’t purchased any solar stuff yet but I have a solar setup in mind, the panels are two 300 watt mono panels which are quite large. The panels measure 65” long by 39” wide, and there are two of them. So ideally I’d want to utilize the space and mount them sideways on the roof of the van as I still want to have 2 roof vents on top (front and back). So my question is will these large panels be ok mounted sideways on the roof? I can’t seem to find many people with large panels like this on a van. I’m planning on bolting them through the roof of the van, but still I’m concerned about a panel ripping off while driving. ANY input/experience on using larger panels would be very helpful and much appreciated!


yes you can mount them that way. On my small astrovan I had a smaller 120 watt panel mounted sideways, it extended a little over the edges. When I got a larger 240 watt panel I was also going to mount sideways to avoid putting it over a vent, but it extended too far over the edges for my liking. Eventually I mounted lenghtwise, I remove the cover off the roof vent and just put the solar panel over it which it cleared by about an inch.

As long as you use 4 “L” brackets, one on each corner of the panel, you should be good to go. Whether sideways or lenghtwise, the bolts will keep it secure. I had them on the roof almost 6 years, lot of freeway driving, panels are on there tight. Nothing says you can’t use 8 “L” brackets to mount them if you want more security. But almost everyone uses 4.

Don’t let the vents dictate how you going to mount them, if you have to put them over the vents, thats an option. Once a panel is over the vent, that will prevent rain from coming in, and it won’t block the airflow. Never had water come into my van from the uncovered vent. You can also instead install side vents. To me it was an eyesore having the panels stick out over the edges.

in this picture you can see the 240 watt panel install lenghtwise, there are a total of 4 roof vents, only one under the panel, the other 3 on the edges. Haven’t use those roof vents in years and instead rely on side vents for ventilation. The “L” brackets I used I bought at home depot for less then 10 dollars, they were longer then the “Z” brackets they usually use to mount solar panels. I needed them long to clear the vents. If I could do it again I would have never installed roof vents and mounted the panel closer to the roof. Just for a neater look.

Thanks for the help and the pictures! I’m hoping the solar panels fit sideways without sticking out. I can’t find dimensions of the roof for my van anywhere online or from the dealership. I know the interior is 73” wide and the pro masters don’t have much of a taper/slant on the sidewalls so I’m hoping they fit nice. I guess that’s the risk I take buying the panels before I actually have the van I ordered. But seriously thanks for your input on this issue, I feel a lot more confident already

1 Like

My panels are 31.8 × 62.2 and mounted sideways. The crossbars in the pic are 65", plus the vinyl end [caps]. 65" panels should fit fine.

More info in this post.

From the pic, it looks like the solar panel roof rack/mount system is custom, and bolted in through the steel roof. Am I correct?

I assume no leaking?
Did you have access to the steel from the interior when you mounted this?
Did you use any special method to mount so as to avoid leaks?

I’m finding many people are afraid to go through the roof… but then again, seems like many people do this with some success, too. Would you comment?

From phone so will be brief. Stock vantech h3 rack for pm. The pm already has rack mounting tabs on the roof that the rack bases bolt onto. So No holes required to mount panels, but one small hole + cable gland required to pass solar wires. I paralleled in the gland and passed one set of wires through.

No leaks. Gland and roof vent mounted on butyl tape, screwed in, and lapped with sikaflex. Pretty standard.

1 Like