diy solar

diy solar

Mobile solar mounting a an odd roof shape

jameshowison said:
Any know of a vent fan that can be mounted on the vertical section of the roof? Seems a shame to put it in the roof, stealing solar space (and creating unpredictable shade patterns). They also drive a lot of heat gain (unless mount under a panel, but then panel is so high!)

Perhaps something ducted? This is 120v so not ideal, but it is exterior mounted. https://www.supplyhouse.com/Fantech-RVF4XL-RVF-Series-Exterior-Wall-Mount-Exhaust-Fan-4-Duct-188-CFM
Click to expand...
Couldn't you just use an inline hvac fan and some nice dryer vent?
 
jameshowison said:
Any know of a vent fan that can be mounted on the vertical section of the roof? Seems a shame to put it in the roof, stealing solar space (and creating unpredictable shade patterns). They also drive a lot of heat gain (unless mount under a panel, but then panel is so high!)

Perhaps something ducted? This is 120v so not ideal, but it is exterior mounted. https://www.supplyhouse.com/Fantech-RVF4XL-RVF-Series-Exterior-Wall-Mount-Exhaust-Fan-4-Duct-188-CFM
Click to expand...
justinm001 said:
Couldn't you just use an inline hvac fan and some nice dryer vent?
Click to expand...
This fan has been on my list for awhile. It’s important for me to keep as much as I can 12v to limit inverter to mini split and wall plugs in.

https://www.etrailer.com/RV-Vents-and-Fans/Ventline/VP-543SP.html#exp-productdetails=.reviews
 
I don't have much time to get on the forum these days so I miss a lot. I have comments for some of the discussion items:
  • VHB tape to hold racking or ridgid glass panels - just f'n stupid. don't do it. pull your panties up and mount them properly with fasteners or....
  • Check out Merlin Solar Trailblazer panels. They are the only flexible panels we recommend and we use them for 90% of our mobile installations. We have mobile medical clinics on the road with these panels. The shells of these vehicles are Turtle Top Odyssey XL on Freightliner chassis. PM me and I can send you datasheets if you're interested.
  • The Maxxair Dome is a decent vent fan that can be mounted on vertical surfaces. It's not going to move as much air as a Maxxair Deluxe, but they are good in small spaces - especially those stuffed with inverters and chargers.
 
K8MEJ said:
I don't have much time to get on the forum these days so I miss a lot. I have comments for some of the discussion items:
  • VHB tape to hold racking or ridgid glass panels - just f'n stupid. don't do it. pull your panties up and mount them properly with fasteners or....
  • Check out Merlin Solar Trailblazer panels. They are the only flexible panels we recommend and we use them for 90% of our mobile installations. We have mobile medical clinics on the road with these panels. The shells of these vehicles are Turtle Top Odyssey XL on Freightliner chassis. PM me and I can send you datasheets if you're interested.
  • The Maxxair Dome is a decent vent fan that can be mounted on vertical surfaces. It's not going to move as much air as a Maxxair Deluxe, but they are good in small spaces - especially those stuffed with inverters and chargers.
Click to expand...
Thanks for the reply! So what’s your background with vhb tape? Like I previously said some say it’s good to use alone and same say it’s not.

I have no problem mounting my panels with more than just the tape. Originally I was going to make an aluminum roof rack with 3-4 legs on either side mounted to the wall framing through the wall panels. It will take a lot of aluminum, planning and time to make. So not set on that being the method of installation

Essentially I’m looking for the most efficient ways that I may not have thought of.


And I’ll definitely check out the Merlin’s! I’m literally completely open on what products to use because we’re still kind of early into our build. 3-4 months will probably be the latest before we start our solar installation. So I have time to brainstorm and research. Where can those panels be purchased? And what’s the longest you’ve had them installed? Just curious if they’ve been used long term

We also are using a a Turtletop for our platform. The VanTerra which is a bit smaller
 
midwestsolarnoob said:
I’ve read so many horror stories on flexible panels! I wish the technology was better it would save so much time and energy. But sadly it’s not.

I do like your idea for a mounting base. I honestly never thought of it before. I could easily make some custom brackets to attach panels. Would it be smart to use two charge controllers with two sets of different sized panels to fill in the extra space? Our whole goal is to be as independent of the grid as possible.

Also using the tape and angle iron would save our roofs integrity. Sadly very thin fiberglass.
Click to expand...
I have had the flex panels, one only made it a few months before dying, and it was secure 100% of the time to a roof. At the time I did not know that it needs air under it and being directly on the roof it burned the fiberglass and discolored it, could have burned the panel to death too. Junk, stay clear of these.

I can get pics if that helps of the angle iron aluminum (angle aluminum) mounted with VHB. I had not heard of the high temp VHB but that is a great idea as to remove the bond I just use a heat gun and at high temp it pulls right off, tho u do have to still pull).
My current rig has the panels laid out longways, front to back, and the angle aluminum is only on the front and back side (short sides of the panel). I used tape all the way across, maybe 18 inch side length, and just used self-tapper/ self-drilling #10 screws to go thru the angle iron and the panel. Way secure.

Is your fiberglass roof smooth or textured? If smooth, then no issues, just clean the roof well before applying tape. If textured then you will want a thick tape and more of it bc tape will not get into the groves so you will need more sq footage of tape to make up for this. I have seen people add Dicore Lap sealant to their tape on the edges of angle iron for more grab. Drill into your roof as a last and desperate resort, you will have leaks and water is death.

The bond is very secure. Unless you mount the panels in a sail formation the wind is not going to be an issue. Mounted flat on the roof and only 1/2 an inch air gap is not going to catch any wind at all. I know many knee-jerk comments are imagining that air will roll over the vehicle and directly hit the panels with full force of highway speeds as if you had an air nozzle aimed an inch away from it, and somehow get under the panel and explode with force, but this ignores all known aerodynamic logic. The air on the roof will be turbulent, and will be going different directions at once. You vehicle is almost certain to NOT have laminar flow therefore will not see direct airflow, and even with perfect flow the panel will be imperfect and cause turbulence. It is amazing to me how little tape I need to secure the panels to the roof, and I could probably stand there and pull the whole thing off with one hand if I wanted to, yet never any issues on the road. Actually, I have one corner on the the back of the rear panels that really are just on there for looks. The angle iron is only 3 inches at each back corner and one of them really does not hold, so is even less secure, and yet, thousands of miles.....

This whole DOT thing... lol, just nod your head and say thank you.

My current camper is camper #6 and all have had taped on solar.

The guy above has no experience whatsoever with VHB tape, noe at all, or if he does he failed miserably using it. It works and it works amazingly. It is fine to disagree but dont use f word to poopoo something that works so well and KEEPs you from drillling f word stupid holes in your roof, lol. Im just kidding, but never drill holes in your roof unless it is to get revenge on somebody really really bad.
You really learn how well it holds when you go to remove it. 1500 degrees of flameless heat will be needed and a scraper or putty knife and a lot of swearing.
 
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midwestsolarnoob said:
Thanks for the reply! So what’s your background with vhb tape? Like I previously said some say it’s good to use alone and same say it’s not.
Click to expand...
I use VHB tape often in our shop, just not for holding down tracks for solar panels on the roof of a moving vehicle. One use for this tape is to hold glass panels onto skyscrapers, so I don't doubt its adhesive properties. I would even grudgingly accept the notion of using fewer fasteners with VHB tape applied along the entire length of the rail and two end fasteners and a middle, but why take the chance of one or more panels coming off the roof and into the windshield of the person behind you?

That's why I believe it's f'n stupid. And I won't do it when customers ask. 75% of the time, once I show them the Merlin panels, show them the installation on the slideout of my personal RV, and tell them the labor cost is far lower to install them with no extra roof penetrations, they agree to try them. In the last 18 months, I've only had one fail and it was due to poor quality seam sealing tape. Once we switched to using 2" Eternabond we've had no failures.

I installed glass panels on the roof of my personal rig three years ago. I installed the Merlin panels on the roof of the slide earlier this year. Their form factor is very low and easily slide under the bulb seal. I used two TBS180L panels in series. We ran the wires along the same cable management device under the slide with the other wires to a separate solar charge controller. The extra 300ish watts covers most of the energy budget for my mini-split A/C. Every watt helps :)

P.S. The heating issues of other flexible panels are well known and I can vouch to it. I had at the time what I thought were the best flex panels I could find, the Sunpower flex panels with the Maxeon cells. They performed well but I only used them as makeshift solar window awnings. About two years ago I came across Merlin Solar when doing some research. I even got to speak with the inventor of the technology and current CEO. They sent me data from Intertek proving the durability in wind testing and partial cell shading that causes hot spots for other manufacturers. He convinced me to give them a try so I ordered a few units to install and test. The panels were purposely designed to be used on curved, flat, commercial, membrane roofs.

We now use them on all of our mobile builds, including commercial builds, unless a customer absolutely must use glass panels.

I'm not selling anything to anyone here on this forum. I'm just giving you my professional experiences with this product.
 
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0truck0 said:
I have had the flex panels, one only made it a few months before dying, and it was secure 100% of the time to a roof. At the time I did not know that it needs air under it and being directly on the roof it burned the fiberglass and discolored it, could have burned the panel to death too. Junk, stay clear of these.

I can get pics if that helps of the angle iron aluminum (angle aluminum) mounted with VHB. I had not heard of the high temp VHB but that is a great idea as to remove the bond I just use a heat gun and at high temp it pulls right off, tho u do have to still pull).
My current rig has the panels laid out longways, front to back, and the angle aluminum is only on the front and back side (short sides of the panel). I used tape all the way across, maybe 18 inch side length, and just used self-tapper/ self-drilling #10 screws to go thru the angle iron and the panel. Way secure.

Is your fiberglass roof smooth or textured? If smooth, then no issues, just clean the roof well before applying tape. If textured then you will want a thick tape and more of it bc tape will not get into the groves so you will need more sq footage of tape to make up for this. I have seen people add Dicore Lap sealant to their tape on the edges of angle iron for more grab. Drill into your roof as a last and desperate resort, you will have leaks and water is death.

The bond is very secure. Unless you mount the panels in a sail formation the wind is not going to be an issue. Mounted flat on the roof and only 1/2 an inch air gap is not going to catch any wind at all. I know many knee-jerk comments are imagining that air will roll over the vehicle and directly hit the panels with full force of highway speeds as if you had an air nozzle aimed an inch away from it, and somehow get under the panel and explode with force, but this ignores all known aerodynamic logic. The air on the roof will be turbulent, and will be going different directions at once. You vehicle is almost certain to NOT have laminar flow therefore will not see direct airflow, and even with perfect flow the panel will be imperfect and cause turbulence. It is amazing to me how little tape I need to secure the panels to the roof, and I could probably stand there and pull the whole thing off with one hand if I wanted to, yet never any issues on the road. Actually, I have one corner on the the back of the rear panels that really are just on there for looks. The angle iron is only 3 inches at each back corner and one of them really does not hold, so is even less secure, and yet, thousands of miles.....

This whole DOT thing... lol, just nod your head and say thank you.

My current camper is camper #6 and all have had taped on solar.
Click to expand...
Definitely not going with any flex panels other than possibly might using the Merlin panels that K8MEJ mentioned. Although they’re very pricey, the technology and online reviews look good. I’m thinking of using a flexible and rigid hybrid system now. Something along the lines of using a flex panel or two for where the roof tapers down at the front, maybe one on the hood? I haven’t done the research on mounting one there yet lol but a heat deflection material interior side on the hood and possibility for an extra 150-200 watts might be worth trying.

I’m always down to see photos of builds!

I’m a professional automotive technician. I’ve done DOT inspections for commercial companies many times. I’m not at all worried about the DOT bs. I was more curious as the references for stating it being a DOT violation


But okay you have definitely swayed me into the tape using. I may still use possibly 3 mechanical fasteners (screws or bolts) per angle iron strip on the roof. I have another idea of mounting custom brackets from 2-3 points on either side wall into the steel frame Then aluminum strips (not mounted through roof) to each angle iron piece. It’ll save my roof and allow for guaranteed anchoring. I’m planing on mounting surround led light pods and bars to these custom brackets. Alittle added safety for BLM land and dark country roads.

I appreciate all the help
 
midwestsolarnoob said:
But okay you have definitely swayed me into the tape using. I may still use possibly 3 mechanical fasteners (screws or bolts) per angle iron strip on the roof. I have another idea of mounting custom brackets from 2-3 points on either side wall into the steel frame Then aluminum strips (not mounted through roof) to each angle iron piece. It’ll save my roof and allow for guaranteed anchoring. I’m planing on mounting surround led light pods and bars to these custom brackets. Alittle added safety for BLM land and dark country roads.

I appreciate all the help
Click to expand...

Low-profile aluminum strut channel with stainless steel hardware is my hardware of choice for solar panel mounting. It won't rust and leave rust stains on the roof or down the side of your vehicle.

Good luck with your project!
 
K8MEJ said:
I use VHB tape often in our shop, just not for holding down tracks for solar panels on the roof of a moving vehicle. One use for this tape is to hold glass panels onto skyscrapers, so I don't doubt its adhesive properties. I would even grudgingly accept the notion of using fewer fasteners with VHB tape applied along the entire length of the rail and two end fasteners and a middle, but why take the chance of one or more panels coming off the roof and into the windshield of the person behind you?

That's why I believe it's f'n stupid. And I won't do it when customers ask. 75% of the time, once I show them the Merlin panels, show them the installation on the slideout of my personal RV, and tell them the labor cost is far lower to install them with no extra roof penetrations, they agree to try them. In the last 18 months, I've only had one fail and it was due to poor quality seam sealing tape. Once we switched to using 2" Eternabond we've had no failures.

I installed glass panels on the roof of my personal rig three years ago. I installed the Merlin panels on the roof of the slide earlier this year. Their form factor is very low and easily slide under the bulb seal. I used two TBS180L panels in series. We ran the wires along the same cable management device under the slide with the other wires to a separate solar charge controller. The extra 300ish watts covers most of the energy budget for my mini-split A/C. Every watt helps :)

P.S. The heating issues of other flexible panels are well known and I can vouch to it. I had at the time what I thought were the best flex panels I could find, the Sunpower flex panels with the Maxeon cells. They performed well but I only used them as makeshift solar window awnings. About two years ago I came across Merlin Solar when doing some research. I even got to speak with the inventor of the technology and current CEO. They sent me data from Intertek proving the durability in wind testing and partial cell shading that causes hot spots for other manufacturers. He convinced me to give them a try so I ordered a few units to install and test. The panels were purposely designed to be used on curved, flat, commercial, membrane roofs.

We now use them on all of our mobile builds, including commercial builds, unless a customer absolutely must use glass panels.

I'm not selling anything to anyone here on this forum. I'm just giving you my professional experiences with this product.
Click to expand...

Thanks for that info - will look into those.
 
0truck0 said:

I used one of these before and liked it a lot. Though I used it on the roof because I put solar panels where the 14x14 vent was and only had room for this round vent.

Roof vents do work on a wall and people do mount them on the wall. The hinge goes up of course.
Click to expand...
How was the noise from it? Was it relatively quiet vs a max air deluxe fan? I like the idea of them because they’re so small and short. Also does it move a lot of air?
 
K8MEJ said:
Low-profile aluminum strut channel with stainless steel hardware is my hardware of choice for solar panel mounting. It won't rust and leave rust stains on the roof or down the side of your vehicle.

Good luck with your project!
Click to expand...
I’m between that and the aluminum angle iron. I might have to use a combination of both. But thanks for all the help!
 
K8MEJ said:
I use VHB tape often in our shop, just not for holding down tracks for solar panels on the roof of a moving vehicle. One use for this tape is to hold glass panels onto skyscrapers, so I don't doubt its adhesive properties. I would even grudgingly accept the notion of using fewer fasteners with VHB tape applied along the entire length of the rail and two end fasteners and a middle, but why take the chance of one or more panels coming off the roof and into the windshield of the person behind you?

That's why I believe it's f'n stupid. And I won't do it when customers ask. 75% of the time, once I show them the Merlin panels, show them the installation on the slideout of my personal RV, and tell them the labor cost is far lower to install them with no extra roof penetrations, they agree to try them. In the last 18 months, I've only had one fail and it was due to poor quality seam sealing tape. Once we switched to using 2" Eternabond we've had no failures.

I installed glass panels on the roof of my personal rig three years ago. I installed the Merlin panels on the roof of the slide earlier this year. Their form factor is very low and easily slide under the bulb seal. I used two TBS180L panels in series. We ran the wires along the same cable management device under the slide with the other wires to a separate solar charge controller. The extra 300ish watts covers most of the energy budget for my mini-split A/C. Every watt helps :)

P.S. The heating issues of other flexible panels are well known and I can vouch to it. I had at the time what I thought were the best flex panels I could find, the Sunpower flex panels with the Maxeon cells. They performed well but I only used them as makeshift solar window awnings. About two years ago I came across Merlin Solar when doing some research. I even got to speak with the inventor of the technology and current CEO. They sent me data from Intertek proving the durability in wind testing and partial cell shading that causes hot spots for other manufacturers. He convinced me to give them a try so I ordered a few units to install and test. The panels were purposely designed to be used on curved, flat, commercial, membrane roofs.

We now use them on all of our mobile builds, including commercial builds, unless a customer absolutely must use glass panels.

I'm not selling anything to anyone here on this forum. I'm just giving you my professional experiences with this product.
Click to expand...
Have you used the vhb tape for plywood to metal ? I’ve seen they made it. Might use it for mounting the sub walls to frame.

Also I do completely understand the idea of having safety nets. As I’m sure also the vhb tape is more than adequate. But I know I could easily add additional mechanical hardware to guarantee a problem free mounting system. We’re going to be traveling and relying on our build full time. So no room for mistakes. Especially if for instance, a low hanging tree limb pull some tape up without us knowing. Next thing we know, $2k in panels gone on a highway.
With that being said I think I’ll have to mount with both the tape and fasteners. It would ease my mind on the road.

The Merlin’s do look good. The technology is smart. I just with I could find some solid reviews on 5+ yr old installs. That would definitely lean me in their direction. Atleast for a hybrid rigid/flex system.

Also what kind of mini split are you using? Have you measured the power use at all? I’m curious of how much to budget towards it outside of the typical 800-1000 watts on most spec sheets. I’ve heard some say they average around 3-500 watts.

Thanks for all the info!
 
midwestsolarnoob said:
Also what kind of mini split are you using? Have you measured the power use at all? I’m curious of how much to budget towards it outside of the typical 800-1000 watts on most spec sheets. I’ve heard some say they average around 3-500 watts.

Thanks for all the info!
Click to expand...
I use an LG 12k BTU 120V mini-split. Above 12k they move to 230-240V units. Power usage is in the neighborhood of 200-600W depending on the temp differential I'm trying to maintain inside vs outside. I have not measured daily consumed energy since I don't really care. The way we use our RV is that most 120V loads are either very small (i.e. TV) or short-duration (microwave). I still rely on propane for cooking and heating water when we dry camp. I just can't get enough solar to quickly replenish my 14.3 kWh battery bank when using electricity to heat water for 3 people and run the A/C all day. And I don't really want to lug a genset around. Even my little Honda 2000i converted to propane is more hassle than I want.
 
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