solar panel mounts

[GlennWest]

Been looking at panel installation pictures on here and others also. Noticed that many use 3 mounts per side on the longer panels. In looking at new panels on line they only have predrilled 2 mounts holes per side. So ya'll think think that is needed on longer panels and why? My Teton rides very smooth. 

[lappir]

I don't yet have any panels. Will the predrilled mounting brackets match up with something solid to screw into? 

If not I might use an extra mount that did. 

Won't know till I decide to do though. 

 

Rod

[GlennWest]

Only one I have mounted was on my truck. Small 100 watt panel. Yes the predrilled holes mated up to the z brackets. I drilled nothing on panel.

[mptjelgin]

I have had panels as large as 260 watts with only four mounts. They were very solid and I had no issues. 

[GlennWest]

Looks like to me if more was needed, more factory holes would be in it for mounts. Now I am leaning toward 530 watt panels. They are 90" long. And they have holes for just 2 mounts per side.

Edited November 28, 2021 by GlennWest

[Chad Heiser]

My cutoff is 60”.  With 60” or less panels, I use two mounts per side.  With panels that are longer than 60”, I use three mounts per side.  

The large residential panels we are discussing here are typically intended to be mounted in a static position on a rail system.  Often no holes are used at all in residential systems.  The mounting rails have squeeze mounts that slide into the mounting rail and then clamp down on the top of the panel frame.

In an RV installation there are more factors to contend with than in a residential installation.  The movement of the trailer as it bounces down the road, tree limbs and other hazards as you drive through RV parks, wind loads potentially from more than one direction at the same time while driving, etc.  Because the RV mounts have to contend with more forces than residential mounts, I error on the side of caution.  

With the 80” REC panels I installed on my rig, I could see the panels bow slightly while they were sitting on saw horses being prepped for installation.  These panels have slim (30 mm if my memory serves) frames rather than the typical thicker (50 mm if my memory serves) frames on many panels though.  

To get three z brackets per side on a large panels, I often have to drill holes.  I have even had to drill holes on smaller panels I only used two brackets per side on to get them in the correct location.  Some panels don’t have matching holes on both sides of the panel.  I basically always plan to drill holes for mounts.  Sometimes I get lucky and don’t have to, but there really isn’t a predictable pattern used across panel manufacturers for frame holes that I have found in my experience.

[GlennWest]

Thank you. What I was searching for. For a 90" panel 3 per side adequate? 

Edited November 29, 2021 by GlennWest

[Chad Heiser]

1 hour ago, GlennWest said:

Thank you. What I was searching for. For a 90" panel 3 per side adequate? 

That’s what I would do.  On my 80” panels, I come in 10” from the end and one dead center on each side.  With a 10” longer panel, I’d probably come in 12” to 15” from the end.

Edited November 29, 2021 by Chad Heiser

[GlennWest]

Thank you again.

[KodiakJack]

Our 305 watt panels have 3 mounts per side.

Later,

J

[GlennWest]

Could one use the residential clamp down mounts on an RV? Know I would likely need to add a screw in top to prevent side movement due to movement of RV. The mini rail system looks like an easy way mount and not very costly. 

[Zulu]

My panels were only 65" long, but I attached my Z mounts to an aluminum rail that was glued & screwed to the roof. So if the panels flew off, the roof would come with them.

[GlennWest]

See I intend to use 500 watt panels. run them opposite of what you posted. I can see getting to center support a problem. They will be 80ish" long. Running in a bolt from top should simplify this. I just thought, Why not use the VHB tape on center support at panel. I could just push down at center. Use angle iron. Need to go taller than z mounts.

Edited December 5, 2021 by GlennWest

[franco-bolli]

Hey Glenn

On 12/5/2021 at 11:38 AM, GlennWest said:

 Running in a bolt from top should simplify this. 

In a previous life, I worked for a solar panel manufacturer that, as have many, went out of buisness in 2012 just before the solar boom took off.

When drilling into the frame around the edge, especially from the top side of the panel, be VERY cautious  that you can determine where the glass stops in the aluminum frame. It used to be that solar panels were made a lot like a sandwhich of layers of materials. If the edge of the glass is nicked or cracked, there goes the 20 year warranty, because it will be a source of moisture or other contaminants getting in and causing delamination of the layers.

If I understand the set up, with two panels side by side lengthwise like this:

_________________
|            |            |
|            |            |
|            |            |
|            |            |
|_______ |_______|

If they are going perpendicular to the vehicle travel and butted up against one another, holding the center down (stable) would definitely keep the flutter or panel vibration down.  BTW, the company I worked for never tested for wind buffeting when mounted on a vehicle and I can't imagine that many companies would.

I don't have a solution to hold them down in the middle gap, that wouldn't require a second elbow in your forearm to tighten the screws. Other than a slight gap between them that will allow access to the bolts that hold the "Z" brackets down which would let you use 3 brackets per long edge.

I have a 260W panel mounted crosswise on my trailer, and I'm using the "luggage rack" on the roof to hold it down. 4000 miles and no issues yet. Everything still seems solid. I have no idea about the vibration it's experiencing. I may need to mount a "go pro" camera on the roof to watch is as I travel.

Using the UHB / VHB tape is a crap shoot. I've used it in places that required a prybar to get apart and others where it wouldn't stick for long.  Both surfaces were cleaned with alcohol, dried, and then lightly warmed the tape and surface. Press and hold for 20+ seconds.  I hope you get good results with your application.

Best of luck, and it will be interesting to hear what you come up with.

 

Edited January 21, 2022 by franco-bolli
added detail about UHB tape

[justRich]

I used well nuts on my current (and previous) camper to secure the panels using only two brackets per side.

[GlennWest]

Two brackets per side is fairly easy. Adding one to center a challenge. Panels I looking at are 80" long. 35mm thick. I could mount panel to a length of angle and then just screw down angle at ends. This would add to cost and weight though. Finding 450 watt in 80" length. My panels will be 7"ish high. Need to clear vent and mini split. That leaves room for lower panels on slides. I could put 4 more lower. Be a little work in that, just thinking out loud. lol

Edited January 21, 2022 by GlennWest

[Randyretired]

I started years ago making my own mounts.  Angle aluminum to attach to the roof and flat and or aluminum up to the side of the panel.  Then bolted through the side of the panel. The aluminum angle on the roof can be as long as necessary, with as many bolts as necessary to meet the needs.  Lots of Dicor.  On the larger panels I also use 3 mounts per side.  At least on the leading edge.  The final bolt placement for the middle mounts are fabricated on the roof to meet the curve.  Mounting the large panels by myself is difficult.  I use equipment to lift the panels up but moving the panel into position without tearing the roof is challenging. 500 watt panels would seem to require 2 or more people and even then it won't be easy.

 

[GlennWest]

That sobering. Might research different panels. See some 370 watt 50ish pounds. Would require two more panels but they are smaller. Be easier to work with

[hemsteadc]

25 minutes ago, GlennWest said:

 Would require two more panels but they are smaller. Be easier to work with

Especially if you want to tilt them.

[GlennWest]

Never will tilt. Unless stoped for months and even then not likely. 

[Randyretired]

I used to tilt when panels were so expensive and the panels were small (100 watts).  Now that the panels are bigger the thought of wind storms catching the panels is to scary.  Even with the small ones I put them down when high winds were forecast. Also getting on the roof is tougher now.

[hemsteadc]

18 hours ago, Randyretired said:

 the thought of wind storms catching the panels is to scary.  Even with the small ones I put them down when high winds were forecast.

I get up to 50% better harvest when tilted, but sitting in high winds blowing directly at their backs is not pleasant when they act like big sails and make the RV rock pretty good... which is where I am right now. 

[franco-bolli]

It's suprising how much energy is lost when there are shadows on the panel. 
Whether caused by overhead branches, leaves settling on the surface of the cells, dirt/ grime or dust from what the wind kicks up at a campsite or from the road.

Take a good look at the other items you have in the area of where the panels will mount. Even though my panel is up off of the roof, the A/C unit or the  roof vent may cast a shadow on the panel depending on which way the sun is oriented in relation to my parking spot.

Considering the panel is mounted in a fixed position, I'm working on an additional set of panels that I can deploy when I'm parked.  I have two more panels that are about 150W and plan on joining them down one long side with a hinge and put a latch with a handle on the opposing long edge so that they can be carried like a suitcase. I'll add another plug in point on the side of the rig so that I can get the solar power to the charge controller.  I'm working on a method to use the extendable legs from a camera tripod to adjust the angle of the panels to get the most energy.

So far, I've collected the hinge and handle parts and machined the alumimun for the tripod leg mounts and have the tripod legs I found at a goodwill store. I have the extra connecting wire and the wall mounted plug.  Now I just need good (read warmer) weather and the extra time I ordered from Amazon (but it's still on back order!) to get this done.
 

The comment about the weight and cumbersome handling of the panels when on the roof should not go un noticed.  I only had one panel, NOT 80" long and it was a bear to handle on the roof, trying to step around all sorts of trip hazards like vents, skylights and A/C units.  Use a buddy and plan what you're going to do with the panel BEFORE you get it on the roof.

 

If someone know how to turn on spell check in this forum, let me know...

[GlennWest]

Tilting has advantages definitely. Going to have mine 7 inches high. Going to do some research and see if I can tilt with an actuator and remote. Just don't want to have to get on roof to do this.

[Darryl&Rita]

Tilting panels came about as a result of $2+ per watt panels. With prices where they are, tilting should only be considered by the young.