Mounting panels

[Black Vulture]

OK, I have a question about how to mount my 2, 100 watt Renogy solar panels on my 2012 Chevy Express.

I bought the van with a really good rack on top and want to carry canoes, kayaks etc... with it so I don't want the panels on the rack.

So, I bolted the panels together using metal brackets (it's solid)

I have the white Drill free solar mounting "corners"
https://www.amazon.com/gp/product/B017BXBLGU/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1
I would like to not have to drill holes into the roof for the panels.

The roof of the van is not flat, it has little valleys (I don't know what you call them)

I was thinking of using butyl tape to fill the "valleys" and PV-804 Neutral Sealant to adhere the 4 corner mounts.

Then some eternabond tape to finish the job.

Has anyone mounted their panels in a similar way?

Any information would be greatly appreciated!!

Jeff

 

[highdesertranger]

a couple of things, that link you posted I cannot find anything. those little valleys are called ribs. I not sure I follow you correct me if I am wrong, the kayaks/canoes are going to be mounted above the panels? if so the panels will not work. even with the kayaks/canoes not mounted up there the shadow from the rack will kill the output of the panels. highdesertranger

 

[Black Vulture]

a couple of things,  that link you posted I cannot find anything.  those little valleys are called ribs.  I not sure I follow you correct me if I am wrong,  the kayaks/canoes are going to be mounted above the panels?  if so the panels will not work.  even with the kayaks/canoes not mounted up there the shadow from the rack will kill the output of the panels.  highdesertranger

I apologize for not being more clear. I'm only gonna use the canoe/kayaks on occasion not full time.

I diddnt know that the small shadow from the roof rack would kill the output of the solar panels.
I assumed the current would just not be as strong from the small shadow.
(yeah, I'm a newbe...lol)

https://www.amazon.com/Drill-free-S...017BXBLGU/ref=cm_cr_arp_d_product_top?ie=UTF8

 

[jimindenver]

You would use 3M very high bond tape with those drill free mounts.

 

[user 37446]

[font=Roboto, arial, sans-serif]Looking up the differences between the mono and the poly (crystalline) panels seems to indicate that poly are more shade tolerant. Mono's are typically cheaper and so you would have to watch what you are buying.  [/font]

[font=Roboto, arial, sans-serif]That's a real "basic" difference, and a possible way for you to choose.  An MPPT controller (versus a PWM) is supposed to harvest more energy due to it's efficiency factor (more expensive too) but thats another can of solar worms...[/font]

[font=Roboto, arial, sans-serif]read: http://energyinformative.org/best-solar-panel-monocrystalline-polycrystalline-thin-film/  dated August 5, 2017[/font]

 

[tx2sturgis]

I diddnt know that the small shadow from the roof rack would kill the output of the solar panels.
I assumed the current would just not be as strong from the small shadow.

Sometimes, depending on the panel, and the size and number of the cells in the panel, even a fallen leaf on the panel is enough to cut power production by a fair amount. 

Each cell in the panel has to pull its weight, and if one is shaded, it can act as a road block in that string of cells.

 

[highdesertranger]

yeah Texas is right, and if that shadow runs all the way across the panel like a rack bar would do it's probably going to cut production to near zero. highdesertranger

 

[frater secessus]

[font=Roboto, arial, sans-serif]Looking up the differences between the mono and the poly (crystalline) panels seems to indicate that poly are more shade tolerant. Mono's are typically cheaper and so you would have to watch what you are buying.[/font]

Mono are generally more expensive, as they are cut from silicon ingots rather than molds.   There is some evidence that poly do have better output in uneven light and mono better output in hot conditions. 

The differences are relatively minor these days.  Assuming there is enough roofspace it's likely fine to buy whatever is cheapest per watt.  If roofspace is at a premium,  mono tends to have higher efficiencies so will have a smaller footprint for a given power rating.

 

[jonsun]

dont fill in the roof ribbing, that makes good cooling/air channels

 

[frater secessus]

I bought the van with a really good rack on top and want to carry canoes, kayaks etc... with it so I don't want the panels on the rack.
So, I bolted the panels together using metal brackets (it's solid)
...
I would like to not have to drill holes into the roof for the panels.

If you mount the panels to the rack (just below flush) you will be able to:

• use the rack to mount the panels (no new holes)
• still use the rack to carry stuff;  caveats about shading as noted before
• and minimize or eliminate shadows from the rack when nothing is carried on the rack  

Do you have pics of the rack on the van?

I'm not carrying anything on my racks but the panels are pretty close to flush and the racks do not shade the panels:



A long item like a canoe would lay across the racks without touching the panels.  

Makenmend mounted his like this.

 

[closeanuf]

I like your rack, where did you get it?  Why did you mount it in the valley instead on top of the rib?  Just wondering.

 

[frater secessus]

That's where the factory rack mountpoints are; I didn't have to drill any holes for the rack. 

The mountpoints are situated on reinforced pads at the edges of the roof.   There is a T-shaped stud welded into each one of the pads;  6 on the regular 136" wheelbase and 8 on the 159" long wb. 

The vantech towerless H1 rack I bought uses two-piece shoes as a base for their crossbars.  You slip the smaller piece over the stud, place the rubber-bottomed piece over that and crank it down.  The smaller piece is snugged up into the bigger one and the T-stud is trapped.  



I'm probably not describing it very well.

 

[Pebbles]

 Why did you mount it in the valley instead on top of the rib?  Just wondering.

I can't answer for him, but for me? I plan on doing that the same way as they will be on the same plane and the ribbing and gives them a hidden look, as well as being a little more aerodynamic because they are now flush. I also think it gives the van a cleaner look then having stuff hangin all over it. Hope this helps?

 

[closeanuf]

Thanks, that's great to have a built in mount. I really like that rack.

 

[Black Vulture]

Sometimes, depending on the panel, and the size and number of the cells in the panel, even a fallen leaf on the panel is enough to cut power production by a fair amount. 

Each cell in the panel has to pull its weight, and if one is shaded, it can act as a road block in that string of cells.

Wow, even a fallen leaf? I never would have thought that.

 

[Black Vulture]

Thanks so much for all the info! I put the panels on last night! 
I used angle irons and 4 u bolts and just  put them right on the rack. 

I guess i can always change it up in the future. 
Im just really anxious to get the van done.

Next is the fantastic fan!

Im trying to put a picture of Bartholomew  (the van) on the forum but cant  figure it out yet...duh...lol

 

[DLTooley]

I too carry roof top boats. My main panel is mounted on my hood, and an older panel is semi-portable and deployed when camped - either on the windshield or leaning up against the canoe. This works good for peak absorption charging.

Let us know if you have any other solution to the boat dilemma.