Foretravel Owners' Forum

Foretravel Motorhome Forums => Foretravel Discussions => Topic started by: goldbehen on November 05, 2015, 08:30:48 pm

Title: A couple questions about solar
Post by: goldbehen on November 05, 2015, 08:30:48 pm
I bought a renology 100w kit consisting of one panel a controller and cable.  Thinking about using it to keep the batteries charged while it sits a while. Considering using commercial Velcro to secure it. If I add in the future I'd look for the self adhesive panels I've read about. Any thoughts on Velcro in this application? Also should I drop the cable into the area where the control panel is located for the inverter  and mount the controller there? Can I access from above to that area and below to get out to the batteries? Thanks
Title: Re: A couple questions about solar
Post by: amos.harrison on November 05, 2015, 08:52:57 pm
I wouldn't trust Velcro.  For temporary installation, I'd use a good caulk.  It'll hold and yet you can cut it off if needed.
Title: Re: A couple questions about solar
Post by: Peter & Beth on November 05, 2015, 10:24:25 pm
I think industrial Velcro will work. The Ramco mirrors use this to hold the mirror pieces in place. Don't ask me how I know.
Title: Re: A couple questions about solar
Post by: jcus on November 05, 2015, 10:43:18 pm
I bought a renology 100w kit consisting of one panel a controller and cable.  Thinking about using it to keep the batteries charged while it sits a while. Considering using commercial Velcro to secure it. If I add in the future I'd look for the self adhesive panels I've read about. Any thoughts on Velcro in this application? Also should I drop the cable into the area where the control panel is located for the inverter  and mount the controller there? Can I access from above to that area and below to get out to the batteries? Thanks
Velco would probably work if you are not driving, use VHB 3m for permanent mounting. With only 100 watts you could put the controller anywhere, but would use at least 12 gauge from the controller to the batteries, or you could just spice it into any 12 volt circuit that is not switched.
Title: Re: A couple questions about solar
Post by: John Haygarth on November 06, 2015, 08:01:15 am
If you are not going to drive while it is sitting on roof why do you need to use anything? I would mount it to a woodwen frame and sit it on roof.
IF you are going to drive with it up there then definitly ise a caulk and 3M tape on all 4 corners at least.
JohnH
Title: Re: A couple questions about solar
Post by: goldbehen on November 06, 2015, 09:46:46 am
Actually I do want the option to drive it. If I caulk and use the 3m tape will that hold it at highway speeds?
Title: Re: A couple questions about solar
Post by: Pierce & Gaylie Stewart on November 06, 2015, 09:55:45 am
GE Silicone II will bond securely if both surfaces are clean when you install it. A razor blade will take it off. $6.24 at HD: GE Silicone II 10.1 oz. Clear Kitchen and Bath Caulk-HD5040 24C - The Home Depot (http://www.homedepot.com/p/GE-Silicone-II-10-1-oz-Clear-Kitchen-and-Bath-Caulk-HD5040-24C/100663319)

Pierce
Title: Re: A couple questions about solar
Post by: wa_desert_rat on November 07, 2015, 05:22:03 pm
Actually I do want the option to drive it. If I caulk and use the 3m tape will that hold it at highway speeds?
The 3M VHB tape is probably safest for driving at highway speeds. No issues for my two 240-watt solid panels at 70mph (downhill). I would think that a scalpel would be able to cut it off. You don't need a lot of surface area; each panel has 4 stand-off mounts and they are about 1.5 sq in in contact with the VHB tape which is in contact with the roof. I used self-leveling caulk over them.

But VHB is rated as more-or-less permanent so you might want to test it on an out-of-the-way spot to see if it can be cut free. 100-watts should cover all your parked needs (with the salesman-switch set to OFF). That's what I'm doing even though I have the unit plugged into 50-amp; I just think that the Classic 150 is a safer battery charging system than any of the alternatives.

Craig

Craig
Title: Re: A couple questions about solar
Post by: John Haygarth on November 07, 2015, 05:30:57 pm
My 5 panels have been on roof 3 yrs and just VHB tape and Dicor levelling caulk to hold each. never moved at all. Would not even worry about it and I check them every 6 ,months.
JohnH
Title: Re: A couple questions about solar
Post by: Dave Katsuki on November 08, 2015, 11:35:42 pm
And our 5 panels have been on the roof with VHB tape and Dicor for close to 7 years with no problems.  If your roof has been painted, need to remove the paint where the VHB tape is going to be applied.
Title: Re: A couple questions about solar
Post by: fouroureye on November 09, 2015, 08:51:32 am
As far as I can tell... mine have been on, like Dave's  for over 12 years... ^.^d

PO had purchased and installed 900watts, did cycle calculations Vs load-charge papers were from 1999
Title: Re: A couple questions about solar
Post by: goldbehen on November 09, 2015, 03:17:14 pm
Should I lay the panel flat and run the tape around the whole frame ? Do I need to take the paint off entirely or use an abrasive like barkeepers to prepare the surface? Thanks!
Title: Re: A couple questions about solar
Post by: rbark on November 09, 2015, 04:22:37 pm
You would want to use brackets on each corner to keep the panels raised off the roof.
Title: Re: A couple questions about solar
Post by: Pierce & Gaylie Stewart on November 09, 2015, 06:20:19 pm
I like about a 1" air space under the panels. The cooler the panels are, the more juice they put out plus the dark color is more likely to  heat the coach interior if they are mounted flat. Also easy to run flex vinyl conduit between and under the panels with the wires inside to make a nice neat job plus no UV for the wires that way.

The larger 6.5' commercial panels should have 6 mounts instead of 4 like the smaller panels have.

Pierce
Title: Re: A couple questions about solar
Post by: fouroureye on November 09, 2015, 07:16:14 pm
The 1" gap is problematic with the cleaning process especially wit 2 panels sidebyside..
Title: Re: A couple questions about solar
Post by: RTG on November 11, 2015, 06:51:30 pm
I don't know if this is heresy, but it seems to me that there is some useful info here:

http://www.youtube.com/watch?v=JT2HwPSEHuk
Title: Re: A couple questions about solar
Post by: Pierce & Gaylie Stewart on November 11, 2015, 08:44:14 pm
Don't see much wrong with mounting the panels this way. There are already over one hundred holes in the roof where vents, antenna, etc have been screwed down. A few more are not going to hurt. Just have to use a tiny bit of sealant.

What is super sloppy is the connection box with enough sealant to plug holes in the Titanic. What were they thinking? Don't like the loose wires on the roof. Easy to use flex vinyl conduit to make a neat installation and eliminate any sun damage and only adds a few $$.

As inexpensive as solar panels are today, it does not take that many to make tilting the panels unnecessary in winter. 600-700 watts along with a MPPT controller are plenty.  Climbing up on the roof at every campground is asking for an accident especially in winter. Converting to LED lighting and TV means full batteries by noon the next day no matter what you do the night before.

I used a stud finder to mount the panels into the aluminum frame but the roof itself is .400" thick so anywhere will really do.

The installation in the video is not what many Foretravel owners would be happy with.

I didn't use adhesive anywhere as I might want to remove the panels to work on the roof, install a vent underneath, replace a damaged panel from falling branches, etc, etc.

Pierce
Title: Re: A couple questions about solar
Post by: Ed W on September 06, 2017, 09:53:26 am
If I screw the panel brackets ro the roof, do I need to be concerned about hitting existing wires underneath? Like around the roof AC units? I have heard people talk about the wire chase. Is that in the edge of the roof where the side wall joins the roof?

Thank you
Title: Re: A couple questions about solar
Post by: John Haygarth on September 06, 2017, 09:59:26 am
Yes it is. If you really want to use screws just use a stud finder or find them (beams) on a damp cool morning as they show up nicely.
I used 3M tape over 4 yrs ago to hold mine and last time I looked they were still there, same place too.
JohnH
Title: Re: A couple questions about solar
Post by: Pierce & Gaylie Stewart on September 06, 2017, 10:15:53 am
I used all screws. The roof is .400" thick (Fiberglas and wood) so I used 3/4" stainless screws to go through the solar panel mount, the roof and the aluminum beams. In a couple of cases, I just used the roof. Worked perfectly.

Pierce
Title: Re: A couple questions about solar
Post by: lgshoup on September 06, 2017, 10:16:29 am
Our panels are held on with 3M tape since 2009 with no troubles. A wise man said that if you think you might need to tilt the panels in the winter then just add another panel so you don't have to get on the roof.

Our first panels were on the coach when we got it. Three 75 watt that were working fine but are approaching the end of their life. I'd built a tile system that allowed them to be tilted left-right and/or front-back. Got a lot of funny looks when I'd ilt them on both axis. Kind of like a big blue diamond standing on the roof.

When I replace the three older panels I'll probably use a 240 watt unit and just tape it over there the three-panel unit is now. The two newer panels that went up in 2009 are 120's so with a new 240 it would bring me up to 480 watts total.
Title: Re: A couple questions about solar
Post by: Tim Fiedler on September 06, 2017, 11:08:02 am
Check the search function for solar panel install here on the forum

Usual method is 3M VHB (very High Bond) tape to attach to roof, no holes in roof

Tim Fiedler

Sure Start Soft Start (http://www.gen-pro.biz)

TCER Direct (http://www.tcerdirect.com) generator-gas-prod (http://www.generatorgasproducts.com) 630 240-9139
Gen-Pro
Title: Re: A couple questions about solar
Post by: Roger & Susan in Home2 on September 06, 2017, 11:33:21 am
Ed, screws will work if you have to use screws.  But they are likely to loosen over time so they should be on your list of things to look at once a year or so.  Use at least two stainless steel screws on each bracket.  The aluminum framing is not real thick so be careful to not strip the threads.  Having to hit a frame member will constrain where your panels will fit. 

The VHB tape works very well.  Even if you use screws I would use the VHB tape.  Maybe your roof is painted.

I suggest locating your panels with the brackets attached in the place where you want then, blue tape around the perimeter of the base of the mount, move the panels and then sand the paint off close to the blue tape.  Clean well, use denatured alcohol. 3M makes a cleaner /bond enhancer to use with this tape.  Use VHB tape, set the panels in place, wait for a day or so if you can and then caulk with 3M 4000 UV from the base of the mount out onto the paint.  Even if the sanded area is 1-3/4" and you use 2" VHB tape you would have plenty of stick and seal the paint as well.
Title: Re: A couple questions about solar
Post by: kenhat on September 06, 2017, 11:54:57 am

Per Kent Speers (Mr. Urethane) use denatured alcohol. It doesn't leave a residue. I keep some in a clear diner catsup type bottle. I can just squirt a little on a rag or directly on the surface and go at it with a stiff brush. Followed by a clean up with a rag.

You're welcome. :)

see ya
ken
Title: Re: A couple questions about solar
Post by: jcus on September 06, 2017, 12:40:06 pm
unistrut - Google Search (https://www.google.com/search?q=unistrut&tbm=isch&imgil=qZw3ZsTFCNVT6M%253A%253BJUFlw-RuVFrxtM%253Bhttp%25253A%25252F%25252Fpipingcomponents.com%25252Fpipe-hangers-unistrut%25252F&source=iu&pf=m&fir=qZw3ZsTFCNVT6M%253A%252CJUFlw-RuVFrxtM%252C_&usg=__DWGK4bi62CrFVQcHDVDjGNmUqCI%3D&biw=1440&bih=777&ved=0ahUKEwjBrbLf_5DWAhUC94MKHfJrD80QyjcIWQ&ei=sSSwWYGRO4LujwTy173oDA#imgrc=qZw3ZsTFCNVT6M:)
This is what the home solar panel installers use. I put the VHB tape on the back of the unistrut and place on roof and use unistrut fasteners to hold panels to unistruts. Because of the great amount of contact area between the entire strut and the roof, never worry about things getting loose.
Title: Re: A couple questions about solar
Post by: Lon and Cheryl on September 06, 2017, 01:04:23 pm
If gluing with 5200 should the gel coat be sanded down to fiberglass for the best bond?
Title: Re: A couple questions about solar
Post by: Jim Sizemore on September 06, 2017, 01:30:13 pm
each panel has 4 stand-off mounts and they are about 1.5 sq

Craig
I attached these to standard door hinges and used 3M 5200 to the roof of my class B over a year ago. I modified the hinges so I can remove the pins to ficilitate tilting the panel(altho I have yet to do so...)
I have since read that 5200 does not like UV but good so far.
Jim
Title: Re: A couple questions about solar
Post by: Roger & Susan in Home2 on September 06, 2017, 01:53:22 pm
Ken, I actually scrubbed with acetone and a scotch brite pad first to make sure any organic stuff (oil, wax etc) was gone and then cleaned with denatured alcohol.  Thanks for reminding me of the denatured bit.  I have no idea what the difference between that and isopropyl alcohol is.  The 3M cleaner / bond enhancer was the last step.

Opinions follow...

A 1.5" square mounting tab is 2.25 sq in x 91 psi tensile strength for the 3M VHB tape is 204 pounds of holding per corner under perfect conditions.  That might be OK for small panels but with any reasonable safety margin not enough for bigger panls.  My 300 watt panels are 39x77.  I used 2"x12" brackets, one per corner. 

I would not use 3M 5200 to bond the brackets to the roof by itself.  Maybe with screws. It is tough and allows for some misalignment with the roof curve but this is not quite what it was intended for.  Seal around the edges of the brackets to keep water and air from getting under them with 3M 4000UV.  Some use Dicor.  I am partial to the 3M stuff.