Using gutter-mounted roof-rack mounts for solar?

[Lasivian]

I'm working on a 1995 Ford E-350 extended van (About 12' x 5' of roof space) that will not be a long-term thing, but I figure I might as well go solar rather than a generator. (I'm planning towards a large sailboat when I find the right one so I might just end up moving the panels from the van to the boat later.)

In the interest of simplicity I was thinking about using 2 or 4 of these roof rack bar mounts and some aluminum rails to tie them together into a platform for solar. (I'm figuring 4x 100 watt panels.)

https://www.amazon.com/dp/B079K8PGS5/

It's more expensive than mounting directly to the roof of the van, but seems much easier to add and remove, plus water intrusion of roofmount holes is no concern. The strength of the mounts concerns me a little bit, but if the rack bars are all bolted into one platform it should be fine.


Thoughts?

Thanks

 

[wayne49]

That rack will work.

Use anti-seize on the gutter clamp bolts/nuts. I had one seize up, I drilled the welded nut out to use a longer bolt and a loose nut. No problems since.

I have an E350 and used a similar, if not the same, rack and pressure treated 2x4s back in 2015. It has worked for six years holding 4 100W Renogy panels in place. The 2x4s I used were 12 footers, there is additional room at the back to strap something down. I have a folding four step ladder that fits across.

The portion of the 2x4s forward of and behind the cross bars have deformed slightly after six years. I don't have a constant load on the ends of the 2x4s. I should cut the forward ends off for cosmetic reasons.

Suggestion, use angled aluminum for the panel supports instead of 2x4s. That is what I, and others, have recently used for panel mounting.

Try to center the weight over the rack tubes. I have the four panels wired as two serial pairs. Each pair is centered over a cross tube.

 

[jonyjoe303]

according to the specs they can hold up to 500 pounds well within the range of a solar panel. If you want to reduce the weight on your roof, instead of getting 4x100 watt panels, get 1x 365 watt or higher panel. It be an easier installation all around and you might only need 2 of these racks.

 

[abnorm]

^But tougher to mount a big panel on a boat later

 

[MrNoodly]

It might be easier to work with racks that use square section tubing rather than round. Easier to drill.

 

[DLTooley]

I’ve installed just one of those 60-72 cell 24v panels this year, love it. If you can pick up from the warehouse they are much cheaper, but harder to ship.

A lot of folks like San Tan Solar in Phoenix. Panels are cheap enough to just leave in place, unless the move is permanent. Do move the battery and charge controller!

 

[Lasivian]

I went with three rack mounts, and 2x 10' galvanized structs shackled to them.



I have 4x renogy 42x20 panels coming. I plan to mount them between the two rails in two pairs.

 

[DannyB1954]

I used gutter mount roof racks and u channel brackets from the big box electrical department. I went with the 160 watt panels as they fit across the roof nicely. If you want a look, my channel is not monitized, so not promoting it for profit
960 Watts for those wondering. I used it to power a 6,000 BTU window air conditioner for my dog if I needed to leave her while shopping. The roof vent was on a thermostat as a backup for the A/C
The brackets
the completed panels

 

[gizmotron]

Wow!

 

[[email protected]]

nice set up,, could have gotten by with 3 roof racks vs 3. they are very strong. we used to carry 3 extension ladders,, a 32 and a 24, plus a 6 ft step and a hand truck.. and on occasion several hundred pounds of wood in the form of 2x4 and 4x4..

they are strong.. good luck..

I used gutter mount roof racks and u channel brackets from the big box electrical department. I went with the 160 watt panels as they fit across the roof nicely. If you want a look, my channel is not monitized, so not promoting it for profit
960 Watts for those wondering. I used it to power a 6,000 BTU window air conditioner for my dog if I needed to leave her while shopping. The roof vent was on a thermostat as a backup for the A/C
The brackets
the completed panels

 

[DannyB1954]

nice set up,, could have gotten by with 3 roof racks vs 3. they are very strong. we used to carry 3 extension ladders,, a 32 and a 24, plus a 6 ft step and a hand truck.. and on occasion several hundred pounds of wood in the form of 2x4 and 4x4..

they are strong.. good luck..

I was more concerned with flexing at higher speeds. The longer the span, the more wind would have an effect. They were not that expensive. I needed two for the back as the roof vent was already there. The rear solar panels also act as a rain cover for the top air conditioner vents.

 

[mjbeam]

I used a pair of the gutter mounts that were on the van when I bought it. I removed the round cross bars and heated the brackets up with a small 1lb acetylene torch and bent them 90 degrees over a cinder block with a sledge hammer then repainted them. I used zinc plated steel slotted angle from Home Depot bolted to the brackets. This was the cheapest solution I could think of. It's been on there for a few years now with no issues. The panels are about 1/2 an inch above the roof of the van in the center.

 

[frater secessus]

It's more expensive than mounting directly to the roof of the van, but seems much easier to add and remove, plus water intrusion of roofmount holes is no concern.

Late to the party, but having an airgap under the panels will help breezes cool them (removing superheated air below the panel). Solar panels make less power as they get warmer.

It will also help reduce re-radiated heat from the panels affecting the van roof, if that's an important factor. When I tested it with a 5" airgap, black panels and white van it was hotter in the shade under the panels than in direct sun because of re-radiated heat. If I were in Alaska maybe I'd want more heat transfer into the van roof.

 

[unaccompaniedsenior]

Late to the party, but having an airgap under the panels will help breezes cool them (removing superheated air below the panel). Solar panels make less power as they get warmer.

It will also help reduce re-radiated heat from the panels affecting the van roof, if that's an important factor. When I tested it with a 5" airgap, black panels and white van it was hotter in the shade under the panels than in direct sun because of re-radiated heat. If I were in Alaska maybe I'd want more heat transfer into the van roof.

Use this principle in the wintertime to almost completely cut off the longwave radiation (heat) loss from the roof of your van. You can even get by without insulation.

 

[Lance22]

Late to the party, but having an airgap under the panels will help breezes cool them (removing superheated air below the panel). Solar panels make less power as they get warmer.

It will also help reduce re-radiated heat from the panels affecting the van roof, if that's an important factor. When I tested it with a 5" airgap, black panels and white van it was hotter in the shade under the panels than in direct sun because of re-radiated heat. If I were in Alaska maybe I'd want more heat transfer into the van roof.

Hmm...

Imagine having the flexibility and knowledge of being able to lower and raise the mounting height of the panels on top of the van to help heat or cool the van as well as help increase fuel efficiency during long hauls or decrease fuel efficiency when just in town..

a fascinating concept...