Mounting solar on an RV roof, slight angle or no?

TucsonAZ · June 2014

I'm about to mount 8 solar panels (6x230w and 2x100w) on a roof, the roof is completely flat and I will be using 2" aluminum angle (1/8th inch) rails running the entire length of the roof on both side of the panels. I was planning to secure the panels with 4 screws though the angle and into the sides of the panel frame on each of the long sides. What I'm wondering is if I should make the fronts slightly (0.5-1.0 inches) lower than the backs to help with the wind forces on them while driving. Do any of you have any experience with this?

BB. · June 2014

Re: Mounting solar on an RV roof, slight angle or no?

A ~5 degree minimum tilt will usually make the panels more "self cleaning" (leaves/dust).

Will you be using exisiting holes in the panel frames or drilling your own? Drilling holes tends to void the warranties.

Also, if you will be using stainless steel hardware--Be sure to use a good amount anti-seize grease on the threads (available from automotive parts stores) on the thread. Many grades of stainless steel will gall and "lock" the threads at the drop of a hat and require you to twist the bolt in half to take apart.

-Bill

TucsonAZ · June 2014

Re: Mounting solar on an RV roof, slight angle or no?

BB. wrote: »

A ~5 degree minimum tilt will usually make the panels more "self cleaning" (leaves/dust).

Will you be using exisiting holes in the panel frames or drilling your own? Drilling holes tends to void the warranties.

Also, if you will be using stainless steel hardware--Be sure to use a good amount anti-seize grease on the threads (available from automotive parts stores) on the thread. Many grades of stainless steel will gall and "lock" the threads at the drop of a hat and require you to twist the bolt in half to take apart.

-Bill

They are the Solarworld 2.0 frames, there are no current holes in them so I will have to drill them, I was planning on just using self tapping screws as there is no access to both sides of the frame to use a bolt and a nut. My biggest worry is the panel getting ripped off the top of the roof while driving.

vtmaps · June 2014

Re: Mounting solar on an RV roof, slight angle or no?

TucsonAZ wrote: »

I was planning on just using self tapping screws as there is no access to both sides of the frame to use a bolt and a nut. My biggest worry is the panel getting ripped off the top of the roof while driving.

There must be a better way... I wouldn't trust self-tap screws to hold them at highway speeds. Also, I assume there must be a way to avoid drilling into the frames of your panels... clamps of some sort. Sorry, I've got no experience or advice other than to say keep researching it. Have you tried any of the RV forums?

--vtMaps

TucsonAZ · June 2014

Re: Mounting solar on an RV roof, slight angle or no?

vtmaps wrote: »

There must be a better way... I wouldn't trust self-tap screws to hold them at highway speeds. Also, I assume there must be a way to avoid drilling into the frames of your panels... clamps of some sort. Sorry, I've got no experience or advice other than to say keep researching it. Have you tried any of the RV forums?

--vtMaps

Well, there isn't much out there on the RV sites about mounting 1,580 watts of solar to a roof much less to an aluminum roof with aluminum studs as they all have rubber/wood roofs.

No clamps that I'm aware of for my application, I do have some ideas to beef it up such making little 1x2 L brackets out of the left over stock and adding a few of those which would act as a clamp of sorts. I could also use 1/4 rivets though I'm not sure if those would be any stronger. I figured with 8 screws in each of them I should be alright.

The Solarworld panels aren't the easiest to mount but were hands down the best price.

Blackcherry04 · June 2014

Re: Mounting solar on an RV roof, slight angle or no?

Have you looked at sites like this ?? I'd probably have a aluminum frame made where the panels slid in and were locked in place in a custom U channel.

http://www.amsolar.com/home/amr/page_24

TucsonAZ · June 2014

Re: Mounting solar on an RV roof, slight angle or no?

Blackcherry04 wrote: »

Have you looked at sites like this ?? I'd probably have a aluminum frame made where the panels slid in and were locked in place in a custom U channel.

http://www.amsolar.com/home/amr/page_24

I have an 8x20 roof that is completely flat without a single opening in it and I need to have the mounting points spaced out to hit the roof studs already up there, what they have would work great for a curved roof or if I was only putting a few hundred watts of solar up there but not for almost 1.6kw of solar.

I could make up some type of slide in system but I'm not sure where or what if any advantage it would offer me, I don't mind a few holes in the sides of the frames at all.

Blackcherry04 · June 2014

Re: Mounting solar on an RV roof, slight angle or no?

Well, I thought it might give some ideas on how other people do it. I have large aluminum shop that builds custom boat hulls 60-100', they can build anything. They have a 20' long shear and brake. I was thinking you might find something like that where you are.

I wouldn't be to hot about self tapping screws, I think they'd work loose. You could drill the frames and set rivet nuts where you could lock the threads.

Vic · June 2014

Re: Mounting solar on an RV roof, slight angle or no?

Tucson..,

As has been mentioned, you really should NOT drill any additional holes in the frames of your SW PVs. It will most certainly void any warranty.

The SW 2.0 frames, as you note, have only small holes for grounding the PV frames.

As you know, the traditional way of mounting these 2.0s is to use top-down clamps that are attached to mounting rails. The rails are attached to roof bracing structure in most applications. Would bet that the vast majority of all PV installations now use top down clamps for mounting PVs.

Am sure that you have seen the standard rails. Here is a link to our host's Iron Ridge brand of rails and top down clamps ... not necessarily what you would want to use ... but here is an example,:
http://www.solar-electric.com/xrsramosy.html.

I could not find a SolarWorld Installation guide, but they probably have recommendations of where the attachment points should be -- it is usually a range of dimensions.

FWIW, Have fun, Vic

BB. · June 2014

Re: Mounting solar on an RV roof, slight angle or no?

Solar World's data/installation sheets:

http://www.solarworld-usa.com/technical-downloads/datasheets

-Bill

TucsonAZ · June 2014

Re: Mounting solar on an RV roof, slight angle or no?

Blackcherry04 wrote: »

Well, I thought it might give some ideas on how other people do it. I have large aluminum shop that builds custom boat hulls 60-100', they can build anything. They have a 20' long shear and brake. I was thinking you might find something like that where you are.

I wouldn't be to hot about self tapping screws, I think they'd work loose. You could drill the frames and set rivet nuts where you could lock the threads.

I'm building the entire RV myself, all systems and right now I don't have the time nor budget to pay somebody to build a $2,500 custom aluminum rack to hold $900 in solar panels. I appriciate your feedback for sure and will seek out an alternate or over build what I'm doing as a result which was already above and beyond what they use for hardware in the link you provided. To give you some idea what I'm working with, this is what the frame specs are:

Attachment not found.

Honestly, I was surprised to hear anybody wouldn't think this was overkill, two 16 foot full rails mounted to aluminum roof beams with full support on both sides of the panels and 8 screws in each, I would think 4 would hold it and 8 would allow for 4 to work loose (something I've never personally had happen in years of rough off-road trails) and still have excess up there. Most RVs actually just "glue" the mounts to the fiberglass roofs?

I should start asking people to post their annual income along with responses as I'm getting the feeling most of you are 6 figures a year or better and I'm only 4 figures a year (:

TucsonAZ · June 2014

Re: Mounting solar on an RV roof, slight angle or no?

Okay, thank you all for the input, truly, I think I'm just going to get all kinds of buck wild crazy and go for this in the old school spirit of things with some self tapping screws.

I do understand the concerns but logic has to kick in at some point, spending $500 plus on a mounting system to keep a warranty intact on $900 in panels seems illogical to me. Not to mention that I'm not sure they even offer their warrantee on mobile installs and from what I've heard, warrantees are about worthless as chances are the company won't be around in 20 years so never buy panels based on warrantee.

I can use rivets over screws, I can even do 4 of each on each panel but from what I'm aware of, there is no mounting system out of the box for 1,500 watts of solar in a mobile application so I was hoping for experience relating to that as I already know what I'm doing wouldn't be correct on a residence.

TucsonAZ · June 2014

Re: Mounting solar on an RV roof, slight angle or no?

Okay, issue's solved, I just ordered 48 high power suction cups and a industrial vacuum pump, I'm going to mount the panels to the roof via suction and the pump will use about 1kw of solar per day I will still have 580 watts left for me, woot woot!

Cariboocoot · June 2014

Re: Mounting solar on an RV roof, slight angle or no?

If we could tone down the sarcasm a bit ...

The problem is the panels you picked are designed to be mounted via clamps. Fine for an application that stays in one place but not so good for one that bumps down the highway at 100 kph. Likewise the self-tapping metal screws are likely to come loose under the same conditions. You'd be amazed how many things get jarred loose going down the road. Especially if your roads are like ours and resemble a lunar surface. I've got the history of destroyed trucks to prove it.

So people quite rightly suggest you look for a firmer mounting. Yes, it all costs money. Too much money these days what with the price of aluminium and all. But protecting that $900 panel investment long-term is the thing.

There ought to be some way to more securely fasten those panels. Corner brackets perhaps. At the very least epoxy the screws.

jonr · June 2014

Re: Mounting solar on an RV roof, slight angle or no?

Loctite threadlocker has a proven history of securing screws and bolts in such conditions. If you don't care about ever getting them off, you could forget about fasteners and mounts and epoxy the panels directly to the roof.

BB. · June 2014

Re: Mounting solar on an RV roof, slight angle or no?

I had a couple of PMs with TucsonAZ--He is looking at using some sort of "pop rivet". He will drill the frames and accept that it will probably void the warranty.

He needs to do the install on a budget (and got a little frustrated)--Pop rivets are easy to drill out for servicing and install new ones--if needed.

-Bill

Blackcherry04 · June 2014

Re: Mounting solar on an RV roof, slight angle or no?

Yep, the cost of racking can be more that the cost of the panel, not a doubt. RV service is a special application for mounting panels. I am not a areo engineer, but I'd say the forces at 70 mph would be great. It might be a place for a deflecting device of some type. It seems like supporting them in the middle of the span might be a good idea, with the regular panel clamps would lock them together.

BB. · June 2014

Re: Mounting solar on an RV roof, slight angle or no?

To reduce wind loading... Something to prevent wind from getting under the panel on the leading edge can help--But may not be necessary as the front of the truck is a big air dam anyway-deflecting over the top of the array (unless the panels are just about overhanging the front of the vehicle).

Another way is to put a "fence" or "spoiler" just before the panels. Spoilers break up the airflow and pretty much kill any lift. Just an L shaped bracket installed before the panels and the top an inch or two above the panels (guessing) will disrupt the airflow enough to kill any lift.

Attachment not found.

-Bill

vtmaps · June 2014

Re: Mounting solar on an RV roof, slight angle or no?

BB. wrote: »

Just an L shaped bracket installed before the panels and the top an inch or two above the panels (guessing) will disrupt the airflow enough to kill any lift.

Or maybe (just guessing) the bracket will create a Bernoulli effect which lifts the panel.

--vtMaps (wondering if anyone has ever set up an off-grid wind tunnel)

TucsonAZ · June 2014

Re: Mounting solar on an RV roof, slight angle or no?

I did look at some wind tunnel results and they eased my mind slightly, not much going on for the first inch or two of the roof that's for sure. I will be using rivets, this truck was made with them anyway, they almost as easy as a screw and will be stronger/safer with this install. I did hear that panels should be a little further away from the roof, that being close impacts them somehow. I will need room to pull wires and stuff so there will be a small gap. I'm also doing two 100w panels at the very front which I can give a much steeper angle to and that should help with the larger panels and up my fuel milage to maybe 5-6mpg.

PS I can't function without the sarcasm, between the solar, fabricating seat mounts, the plumbing, the needed mechanical work on the truck and the budget, it's either sarcasm or strong narcotics.

zoneblue · June 2014

Re: Mounting solar on an RV roof, slight angle or no?

I guess you have two choices, go with the edge clamps, or drill the frames. If you go the latter route, then im with the others, tapping is out. What ive seen people do for RVs is a two peice bracket. You first bolt one bracket to the pv frame. Then bolt that bracket to the roof mounting bracket. Make sense? The brackets sticks out some so you can get at it.

Our local installer guy tells of instances where edge clamps have cascade failed, ie with the early gen mid panel clamps releasing in sequence after a single edge clamps fails. Not sure id be keen to use them on a RV. To much movement, vibration, maleability of al etc.

You ideally want some clearance for airflow, but many RV folk feel thats a luxury they cant afford.

Re panel waranty, i doubt any of these companys will be around in 25 yrs to honor the waranty anyway, but what you want to cover your butt on is any early (manufacturing defect) failures. Ask Bill about how that can happen. Thats a gamble youll have to take, seeing as you dont appear to have many choices.

Chris · June 2014

Re: Mounting solar on an RV roof, slight angle or no?

My RV is perminntly parked, but when I installed panels on the father inlaws motor home I used Z brackets....the ones in the center column here http://www.papsolar.ca/page_5.htm

And yes....all 6 panels I had to drill the frames to mount the brackets over a roof truss

TucsonAZ · June 2014

Re: Mounting solar on an RV roof, slight angle or no?

Chris wrote: »

My RV is perminntly parked, but when I installed panels on the father inlaws motor home I used Z brackets....the ones in the center column here http://www.papsolar.ca/page_5.htm

And yes....all 6 panels I had to drill the frames to mount the brackets over a roof truss

That's awesome Chris, it's nice to hear from somebody that's actually mounted them in a mobile environment. Did you use 4 per panel? I would have gone that route but it was more costly than the rails and wouldn't give me the freedom of mounting the panels anyplace I desired. Did you just use normal screws and follow up with Dicor on the roof? Normal screws into the bottoms of the panels as well or they're bolts right?

Chris · June 2014

Re: Mounting solar on an RV roof, slight angle or no?

Yup, just 4 per panel, but they were only 100 watters.......any bigger and I would have gone with 6. The Z brackets came with bolts and lock washers for panel attachment.......then for mounting to the roof I used a course 1" wood screw with Dicor on and under the brackets.

I found that wile drilling into the back of the frame if you place a chunk of 1X6 between the glass and aluminum it removed the stress of damaging the under side of the panel

Hope that helps

TucsonAZ · June 2014

Re: Mounting solar on an RV roof, slight angle or no?

Chris wrote: »

Yup, just 4 per panel, but they were only 100 watters.......any bigger and I would have gone with 6. The Z brackets came with bolts and lock washers for panel attachment.......then for mounting to the roof I used a course 1" wood screw with Dicor on and under the brackets.

I found that wile drilling into the back of the frame if you place a chunk of 1X6 between the glass and aluminum it removed the stress of damaging the under side of the panel

Hope that helps

It just makes me feel a little better about them not going anyplace with my setup. I have seem some mountings I thought were fairly crappy for sure, not safe by my standards. I can't screw into the backs of mine so I will have to go at them from the sides but with rivets I'm becoming fairly confident they will be staying where I put them. Oddly, I feel more comfortable with wood and screws even though I'm fairly certain the metal/rivets are much stronger.

Thanks a lot Chris!

Mustang65 · June 2014

Re: Mounting solar on an RV roof, slight angle or no?

I mounted my 250watt panel directly to the roof of the travel trailer (after consulting a few companies that install them). Since my travel trailer has a truss roof, I placed rubber padding between the center of the panel (front/rear) and the roof. The "Z" brackets worked great. I used large wood screws (as recommended by the installers) to anchor the 8 brackets to the roof. I check the bolts and caulking at every campsite. None of the bolts have required adjustments yet. So far the panel has gone 8,350 miles with no sign of any problems. It even survived the western Kansas wind gusts while driving to Denver last year. I will be adding one additional 250 watt panel on the front of the travel trailer's roof later this year along with 2 additional batteries to up the Ah to 520Ah, as we are planing longer dry camping trips.

So far, this setup has produced 8,511Ah and 113kWh according to the MorningStar MPPT LIVE data display. The travel trailer's internal battery charge controller has been turned off since the panel was installed.

One HAPPY (SOLAR) CAMPER,

Don

2013 Jayco Eagle 284BHS
250Watt Grape Solar Panel, MorningStar MPPT 60 Charge Controller
1500 Watt Ramsond PSI, 2 Trojan T145 Batteries (260Ah)
2 - AirSight Wireless IP Cameras (used as rear view cameras)
EnGenius WI-FI extender, D-Link wireless (n) modem
MagicJack Internet Phone
2012 Ford F150XLT, EcoBoost w/3.73
157" Wheel base, HD Towing Package

Attachment not found.

TucsonAZ · June 2014

Re: Mounting solar on an RV roof, slight angle or no?

Mustang65 wrote: »

I mounted my 250watt panel directly to the roof of the travel trailer (after consulting a few companies that install them). Since my travel trailer has a truss roof, I placed rubber padding between the center of the panel (front/rear) and the roof. The "Z" brackets worked great. I used large wood screws (as recommended by the installers) to anchor the 8 brackets to the roof. I check the bolts and caulking at every campsite. None of the bolts have required adjustments yet. So far the panel has gone 8,350 miles with no sign of any problems. It even survived the western Kansas wind gusts while driving to Denver last year. I will be adding one additional 250 watt panel on the front of the travel trailer's roof later this year along with 2 additional batteries to up the Ah to 520Ah, as we are planing longer dry camping trips.

So far, this setup has produced 8,511Ah and 113kWh according to the MorningStar MPPT LIVE data display. The travel trailer's internal battery charge controller has been turned off since the panel was installed.

One HAPPY (SOLAR) CAMPER,

Don

2013 Jayco Eagle 284BHS
250Watt Grape Solar Panel, MorningStar MPPT 60 Charge Controller
1500 Watt Ramsond PSI, 2 Trojan T145 Batteries (260Ah)
2 - AirSight Wireless IP Cameras (used as rear view cameras)
EnGenius WI-FI extender, D-Link wireless (n) modem
MagicJack Internet Phone
2012 Ford F150XLT, EcoBoost w/3.73
157" Wheel base, HD Towing Package

Attachment not found.

That's awesome and it looks great! I was on the 5th wheel bandwagon for a long time, that and motorhomes but I hate the leaks and the rot, I have never seen one I couldn't find it on, so frustrating and you need to be ever vigilant to make sure none of them develop. This is what caused me to go down the stepvan/utilimaster path, all aluminum and the construction is amazing if you don't mind putting in the copious amount of work needed to have a functional living space. I will say this however, were it not for my health issues I would have been very content in a 5th wheel and my F-250 five speed with the inline six!

On the flip side, here's a picture of the Utlimaster before I started cleaning it up, it's really hard to beat the access and ease of working on it, out of the rain, inside the "coach", and come on, a SBC 350 is about as cheap and easy to get parts for as they come!

Attachment not found.

Mustang65 · June 2014

Re: Mounting solar on an RV roof, slight angle or no?

Here is the wiring diagram of the Travel Trailer. I wired it so that I can just plug in the shore power into an outlet that is wired to the inverter or an outlet that is connected to the shore power plug. Not a fan of the automatic switch. When you finish installing your panels, post a picture... would love to see it. We are in the Georgia Blue Ridge Mountains for the next 4 months... just returned from Nashville for the Country Music Awards week... need to rest now, concerts every night. In October I need to head back home to finish installing the 10 solar panels along our privacy fence. Always something going on.

Don
2013 Jayco Eagle 284BHS
250Watt Grape Solar Panel, MorningStar MPPT 60 Charge Controller
1500 Watt Ramsond PSI, 2 Trojan T145 Batteries (260Ah)
2 - AirSight Wireless IP Cameras (used as rear view cameras)
EnGenius WI-FI extender, D-Link wireless (n) modem
MagicJack Internet Phone
2012 Ford F150XLT, EcoBoost w/3.73
157" Wheel base, HD Towing Package
Attachment not found.

ZoNiE · July 2014

Re: Mounting solar on an RV roof, slight angle or no?

Have you considered getting a 2"x2"(or whatever your panel thickness is) aluminum "C" channel and bolting them down the roof, then sliding the panels in? I'd look at doing something like that, with some rubber or weatherstripping on the bottom to keep them tight, with caps on the ends so they cannot slide out? I think this may be your best bet. Protection from wind, and no holes in the panels.

You may find this at Homeowner depot/Lowes, or try grainger or maybe a company that makes covered parking structures or commercial windows or something like that. Look for "Mullions."

Attachment not found.
http://ddmgaragedoors.com/parts/part/BRA-200300C.html

I have three 200 series solyndra panels that I plan to mount in a similar manner. MY problem is getting a small inverter that will take the High input DC voltage these things use. They are not normal. The tube design should help with the wind going down the road.

TucsonAZ · July 2014

Re: Mounting solar on an RV roof, slight angle or no?

ZoNiE wrote: »

Have you considered getting a 2"x2"(or whatever your panel thickness is) aluminum "C" channel and bolting them down the roof, then sliding the panels in? I'd look at doing something like that, with some rubber or weatherstripping on the bottom to keep them tight, with caps on the ends so they cannot slide out? I think this may be your best bet. Protection from wind, and no holes in the panels.

You may find this at Homeowner depot/Lowes, or try grainger or maybe a company that makes covered parking structures or commercial windows or something like that. Look for "Mullions."

Attachment not found.
http://ddmgaragedoors.com/parts/part/BRA-200300C.html

I have three 200 series solyndra panels that I plan to mount in a similar manner. MY problem is getting a small inverter that will take the High input DC voltage these things use. They are not normal. The tube design should help with the wind going down the road.

That would be a good idea though I would like the panels at least an inch off the roof just to keep them cooler. I'm fairly certain I will be fine, I'm planning to do 1/4" grade 8 bolts at 24" centers with each panel held into the rails via eight 3/16th rivets, this should offer me a very solid mounting, less heat on the panels (surface temps on the roof can be 170+) and I can't imagine a world they will be going anyplace that doesn't result in my own death.

Should I need some changes I will certainly look into your solution.

Iceni John · July 2014

Re: Mounting solar on an RV roof, slight angle or no?

I'm presently making support frames for my eight Sharp 255W panels that will be on my bus. I buy almost all my metal from Industrial Metal Supply - they have a new branch in Tucson. I bought my 6061 angle and 6063 channel from them, along with the stainless tubes for the telescoping support struts and the stainless piano hinge. IMS stocks most of the standard sizes of aluminum and steel, such as these: http://www.metalreference.com/10%20AL%20Ext%20Channel%20Equal.htm Otherwise, Orange Aluminum stocks some sizes and extrusions that IMS doesn't carry, but shipping to AZ could be expensive.

Definitely keep enough airgap under the panels so air can naturally convect under them, but also make the panels easily detachable just in case you have to replace one. Stainless hardware may be better than gr.8, but use plenty of anti-sieze to prevent thread galling.

John

Mounting solar on an RV roof, slight angle or no?

Comments

Categories