Removing flexible solar panels mounted with VHB tape

DougH

If anyone else has used 3M's VHB tape to "permanently" mount flexible solar panels, once (or if) the panels die, you might be wondering how to get the permanent Very High Bond mounted panels back off without scratching up the T@B.  I did try a utility razor and such and couldn't even budge the corners of some panels we mounted (that passed on due to hail damange).

I don't think I read it on this forum (or the dementia is kicking in today), but someone suggested using the same thing windshield repair folks use to remove the adhesive on automobiles.

Worked like a charm.  Like cutting through warm butter.  Only took a few minutes to remove both panels that I'd way too thoroughly attached to the T@B.  Amazon has several offerings to help, and I ended up using the handles from one kit and the wire from another.  Then a microfiber cloth and WD-40 to remove the remnants.

http://a.co/d/8AUhb1i

http://a.co/d/9e6HCRQ

dhauf

DougH did this end up scratching the aluminum at all?  That is a great idea BTW.  I have used fishing line before to remove car badges etc.  Also did you have the factory solar set up that you removed?  Or was it something you stuck down?  I have the factor solar with the flexible panels and they seem pretty well stuck down as well.  I was wondering the same thing if any of those panels went bad and had to be replaced.  Great idea!

DougH

@dhauf : One small half inch scratch.  Not bad, and it adds further character to all the hail dents up there.  I'll cover it before putting the new panels up.  Not factory solar, just some inexpensive Amazon 100W.  Did I read correctly that the new factory solar option is just one 190W panel?  Couldn't find anything like that on Amazon.  So I just replaced mine with the BougeRV ETFE 100Ws.

dhauf

@DougH ok that’s not bad if it’s just a small scratch.  Once it’s got a new panel on you won’t see it.  Yes it seems the new T@b 400’s come with one 190w panel now.  Not sure about the 2019 T@b’s. I currently have a 2018 and it came with factory solar.  It had one 100w and one 50 panel in parallel on the roof.  I’ve had a bunch of issues with my new 2018 so NuCamp is building me a replacement 2019 unit.  I’m curious to see if they have changed to solar configuration any in the newer models.

DougH

I'm putting those BougeRV (Amazon) 100W panels on, so I glued a heat insulating layer to the panels and just placed them up their to see if it helped keep the roof cooler (I have a thermal camera).  It did.

The rough ETFE layer these new panels come with is supposed to help protect the panels and also pull in light at lower angles.  It really works.  Took this shot (haven't even taken the plastic packaging wrap off yet) with camper facing South, and with the sun getting ready to set at 16 degrees off the horizon.  The panels in series were still putting out 34.4V!!!  Not like my last set at all.  Not sure I need a third panel anymore if I only run the A/C a few hours a day.  Then again, now each panel cools the roof more, so.....

dhauf

That’s pretty cool.  I see some plastic over the top of the panels as well in that picture.  What is that?

DougH

Just packaging protection film.  Haven't peeled it off yet.

dhauf

Ah ok I kind of figured but wasn’t sure.  I also bought two 100w panels from amazon recently, they are allpowers brand and seem to work pretty well.  I was thinking of adding them to my system as well.

DougH

Nice.  I couldn't decide whether to go with what I did or the AllPowers, so just flipped a coin.

dhauf

I think they are both pretty similar.  I went with allpowers since I got them for $139 a piece on prime day.  What was the foam insulation you ended up using under the panels?  Sounds pretty good.

DougH

Fantastic deal.  Envious.

Heat Barrier (plenty of different sizes) : https://www.amazon.com/dp/B016QURUKA

rfuss928

Most panels need to dissipate heat.  Are you sure mounting to insulation is good for the panels?

DougH

I don't know.  I know the previous panels were subject to 130F+ VHB'ed directly to roof.  That thing gets toasty (dominant conduction vs. lesser natural convection off top surface). Without a rack, I was hoping this might cool the cabin and be better for panel efficiency.  Time will tell, or am I doomed?

dhauf

I can’t see how this would be any worse for the panels than installing on asphalt roof shingles which probably get even hotter.  The flexible panels are supposedly rated for installing on a roof so I’m not entirely sure either, but guess time will tell.  Good thing is they are relatively cheap so even after a couple of years if they break just get some new ones.  Probably by that time something better will be out there anyway.

Spectre9

Not that I have done an install over insulation, but I have had it in an RV for a few years and it falls apart. I hope the edges were direct-glued to the camper or someday you might lose some panels!

DougH

Didn't edge attach, but I ran a thick attachment wire through the grommets on each panel and around the air vent.  So if the insulation dissolves and panel comes loose, at least it won't fly off somewhere.

JonW

I mounted a flexible solar panel on my aluminum teardrop roof several years ago.  Has worked fine and no damage to the panels for 3 years, and the aluminum is painted dark grey and can get quite hot in the sun.

I didn't glue or use VHB tape to attach it to the roof.  I used aluminum U channel for the bottom and just aluminum bar at the top to hold it down.  I'm in the process of doing the same thing on my T@B and will post pictures when I'm done (probably in about a week).

Dalehelman

While attending the Fort Wardon rally this weekend. The subject of direct roof mounted solar panels heat dissipation was discussed. This product was suggested. Adam claimed it was very successful in dissipating heat.

Coroplast 48 in. x 96 in. x 0.157 in. White Corrugated Plastic Sheet

See this on Homedepot.com

OMSID#: 205351385
Store SKU#: 1000118572

OpenSky

Coroplast is polypropylene.  VHB (and most adhesives) don't work well with polypropylene, so I'd be concerned about reliable adhesion.  Was the bonding method discussed?

Glad to see the post about successful use of a cutting wire with VHB. I figured it would work with silicone adhesive, but was thinking it would not be successful with VHB tape due to the thin bond line and the integrity of fhe tape itself. 

I've been contemplating bonding a flexible panel to a thin sheet of aluminum (with VHB or silicone), then bonding that aluminum panel to the top with some (4-6) aluminum strips bent to conform to the curve of the T@B, as spacers.  This allows air convection under the panel to cool the panel (and the aluminum sheet provides a degree of thermal uniformity).  But, a lot more work (and expense) to install.

JonW

I used Coroplast in my teardrop in a few (interior) places.  I'd be concerned about it melting once the roof got hot from sitting in the sun.

Although I'm not sure it's really necessary, I'm planning on putting a layer of thin foam (a cut-up yoga mat, actually...) between my T@B roof and my flexible panels.  You couldn't do this if you were using VHB tape to attach the panels.

Ratkity

Wow, I love all this expertise! Keep it coming!

DougH

@OpenSky : Some of the newer panels tout a thin layer of copper or aluminum integrated right into the panels to eliminate the hot spots that were the scourge of solar cells a few years ago.

I put a heat insulator between the dark heat absorbing panels and rooftop primarily to keep the cabin cooler, not just for panel efficiency.  But something to allow flow under the panel would have been nice, so I'll avidly follow what folks come up. 

I tried to find studies on panel efficiency, longevity, and dissipation with hard numbers to justify the extra effort of spacers, but as @dhauf suggests, if a $100 panel only lasts a year or two, the next time around they'll be much more efficient... or in a couple years Nucamp will be offering a fusion powered, expandable, hover-T@B toy-hauler as an upgrade (went to an RV show yesterday and the tech keeps getting better).

dhauf

DougH said:

@OpenSky : Some of the newer panels tout a thin layer of copper or aluminum integrated right into the panels to eliminate the hot spots that were the scourge of solar cells a few years ago.

I put a heat insulator between the dark heat absorbing panels and rooftop primarily to keep the cabin cooler, not just for panel efficiency.  But something to allow flow under the panel would have been nice, so I'll avidly follow what folks come up. 

I tried to find studies on panel efficiency, longevity, and dissipation with hard numbers to justify the extra effort of spacers, but as @dhauf suggests, if a $100 panel only lasts a year or two, the next time around they'll be much more efficient... or in a couple years Nucamp will be offering a fusion powered, expandable, hover-T@B toy-hauler as an upgrade (went to an RV show yesterday and the tech keeps getting better).

@DougH Agreed! I think we tend to overthink this so many times.  I have a few different flexible panels some even mounted to the roof of my shed right on top of the shingles and have had no issues for at least a year so far and never put any other backing behind it.  I get almost 85-90% of the rated power on them, they are 100W panels.  On the factory set up also on my new 2019 Tab looks like they just mount it directly using some adhesive tape and doesn't seem to have anything behind it.  I would say stick it on and use it and don't worry about it.  The technology is changing so rapidly and the prices are getting cheaper every day on these panels.  I use a spray on wax on the top of the panels and use a microfiber cloth to keep them looking nice and shinny.  Other than that I don't worry about them.

DougH

@Spectre9 : You're psychic!  Just went on a tour through the Rockies.  Panels held fine until I got 40 miles from home (after almost 3000 miles), then the heat insulation layer on one panel gave up.  I had it wired down so it wouldn't fly off, but as you mentioned, I should have glued down the edges! 

Adam_Hough

I did not think about mounting my solar panels to the twin wall corrugated plastic sheets until after I had mounted them using eternabond tape.  The heat loss efficiency percent of a direct mount solar panel is roughly 9%. 

https://www.solar4rvs.com.au/blog/news-2014/flexible-solar-panel-product-testing/

https://nebula.wsimg.com/067a0b086bcdbb011d73c983b5cabcee?AccessKeyId=69CC3057D53E066A8205&disposition=0&alloworigin=1

As for the plastic panels taking heat, many of these panels are designed the be used on greenhouses.

https://www.greenhousemegastore.com/solexx-pro-52-in-wide-per-linear-foot?gclid=Cj0KCQjw3KzdBRDWARIsAIJ8TMTpoT_0QY2bbVBPwUpppCnwpiVwzB6RRrxNOcNK1RVQaIYkPs67zkoaAiA0EALw_wcB 

I have not actually research which bonding method would be best yet.

- Adam

 

Adam_Hough

Also the melting point of coroplast is 160*C (320*F) so it is doubtful the trailer would survive if the melting point was reached.  

<a href="https://www.coroplast.com/pdf/Corrugated%20Packaging%20&%20Graphic%20Grades_msds05212014.pdf" title="Link: https://www.coroplast.com/pdf/Corrugated%20Packaging%20&%20Graphic%20Grades_msds05212014.pdf">https://www.coroplast.com/pdf/Corrugated%20Packaging%20&%20Graphic%20Grades_msds05212014.pdf</a>

DougH

@Adam_Hough : Yup, the folks thinking of sandwiching something insulative between their flex panels and the roof are primarily just trying to keep a bit more heat from finding its insideous way inside (RE the solar4rvs article). Fortunately winter camping season is coming.

OpenSky

So an interesting approach might be corrugated roofing panels with the "hat" cross-section (trapezoidal rather than curved waves).  If fiberglass, or metal without rework, the channels would need to run laterally, but this would allow airflow behind the solar panel.  Basically, you run VHB or silicone adhesive on one face, lay it on the roof, then on the other face and lay the panel on this.

From a heat removal perspective, this is suboptimal due to the side-to-side channels which don't reinforce convection  or undertow-airflow.  But still much better than no airflow.

If one was ambitious, with a metal panel one could curve it by repeatedly rolling a hard roller in the channel of the side which will adhere to the solar panel, thus expanding it.  This would allow the airflow to have a vertical (and fore-aft) component.

DougH

@OpenSky : I also thought about running a few rectangular aluminum pieces (readily available) across the width (screwed in at side) and jump up to 400W with rigid attachment points at all four corners of each panel with a couple braces and VHB just for mid-support.  But then I remembered @dhauf 's wise admonition.  So I'm just going to clean up the roof and simply VHB the panels directly to the roof.  I feel like such a quitter.  As a consolation, I'll offset them so I can add a third panel as Christmas present.

druthazer

dhauf said:

DougH said:

@OpenSky : Some of the newer panels tout a thin layer of copper or aluminum integrated right into the panels to eliminate the hot spots that were the scourge of solar cells a few years ago.

I put a heat insulator between the dark heat absorbing panels and rooftop primarily to keep the cabin cooler, not just for panel efficiency.  But something to allow flow under the panel would have been nice, so I'll avidly follow what folks come up. 

I tried to find studies on panel efficiency, longevity, and dissipation with hard numbers to justify the extra effort of spacers, but as @dhauf suggests, if a $100 panel only lasts a year or two, the next time around they'll be much more efficient... or in a couple years Nucamp will be offering a fusion powered, expandable, hover-T@B toy-hauler as an upgrade (went to an RV show yesterday and the tech keeps getting better).

@DougH Agreed! I think we tend to overthink this so many times.  I have a few different flexible panels some even mounted to the roof of my shed right on top of the shingles and have had no issues for at least a year so far and never put any other backing behind it.  I get almost 85-90% of the rated power on them, they are 100W panels.  On the factory set up also on my new 2019 Tab looks like they just mount it directly using some adhesive tape and doesn't seem to have anything behind it.  I would say stick it on and use it and don't worry about it.  The technology is changing so rapidly and the prices are getting cheaper every day on these panels.  I use a spray on wax on the top of the panels and use a microfiber cloth to keep them looking nice and shinny.  Other than that I don't worry about them.

druthazer

@JonW.    Do you have photo and how you finally installed?   

I am getting ready to install 2 X Renogy panels.   

Thought about corogated plastic as insulating layer.  Saw something interesting on you tube  RV by Tito...  

How about where you mounted the panels and what orientation?   Thinking one fire-aft on right side of vent and one across behind vent.

Any new thoughts?

Maybe overthinking?