I am going to install a 100 watt Renogy flexible solar panel to the top of my 2350 Phoenix Cruiser. It will supplement the existing 100 watt regular Renogy panel I installed earlier this year. The 100 watt does an OK job keeping the batteries charged when boondocking, but I need just "a wee bit more" power as Scottie used to say on Startrek. This panel only weighs about four pounds and is 42" by 21" by about an eighth of an inch thick. Here it is:http://www.amazon.com/Renogy%C2%AE-Monocrystalline-Bendable-Solar-Panel/dp/B00IK19VF6/ref=sr_1_1?ie=UTF8&qid=1404922295&sr=8-1&keywords=renogy+flexible+solar+panelMy question is this: what should I use to fasten this on the roof with? On the first panel I installed, I made struts, used Z mounts, drilled into the roof and sealed all the mounting with Dicor. Since this one is light and flexible, it can be mounted directly flat on the roof and I don't know whether to use 3M tape, stick it down with DICOR or use some kind of exterior construction glue. Any comments or suggestions would be great. The diameter of the small grommets on the panel would only allow for using a screw of about 3/16" diameter if I drilled into the roof, which I would really like to avoid, so I would like just to stick it on there using something. Thoughts?PSW

Up to you but I would not stick anything to the roof. Note that you would be sticking to the membrane and that may/may not void any warranty you might have. These membranes are delicate enough as it is.If I were you I would fasten it to a frame then apply the frame to the roof using screws (which you already have anyway). The frame would be of a big enough size to allow some growth, just in case down the road that "wee bit more" is not enough.

IMHO - if it is not screwed / bolted to the rig, there is a very high risk of loss during travel!!

I know a couple who have traveled thousands of miles with a solar panel stuck to their fiberglass trailer's roof with VHB tape, and they have had no trouble. The VHB tape seems up to the task. But if you have a membrane roof, I don't know how strong that stuff is.

I have a brother that works for 3M. He gave me a roll of their high strength tape and said it would be fine with my 100 watt panel. Me being an engineer used the tape under the feet and then covered the top of the feet with Eternabond. 2 years later I still have no doubts it is on there for good. Hope I never have to remove the panel from my fiberglass roof.

I taped mine down with eternabond tape and no problems with it.

Glue, Tape or ? to attach a light weight solar panel?

Almot
Explorer III
Aug 01, 2014
PSW wrote:
Believe me: all 200 watts of solar will do is keep your batteries topped out assuming you use good battery management techniques. It won't be enough to really run anything.

I think 200W is more than one needs for maintaining 2*6V in a parked rig with everything off. 50W panel would do just fine.

OTH, for living, 200W is just barely enough. On a bright day it would supply the charge lost on a few lights, pumps, an hour or two of laptop or a TV, and hour or two of furnace (intermittent cycling), and parasitic loads - DC circuit of fridge, sensors etc. Many people wouldn't need anything else. As long as you avoid running high-power 110V devices like microwave, toaster, hair drier etc, and the weather is not terribly bad - it is possible to live off 200W solar. Energy conservation and battery monitor is a must, in this case.
PSW
Explorer
Aug 01, 2014
Believe me: all 200 watts of solar will do is keep your batteries topped out assuming you use good battery management techniques. It won't be enough to really run anything. There are a lot of posts over these years on battery management and a search will bring them up. Almot is right on target with his post immediately above. These panels are not generators, they are supplementors only.

Paul
Almot
Explorer III
Aug 01, 2014
dapperdan wrote:

My goal is to try and keep our 2 6 volt batteries close to full while parked at our storage lot (with no electricity). We have a residential fridge which, with an inverter will run a couple of days on our batteries or so the salesman said. I just want to be able to fire up the fridge before loading it up for a trip and NOT discharge the batteries too much, my thought is a couple of 100 watt panels will do the trick.

I think salesman lied. In 2 days a 12-15 cu.ft size residential fridge with inverter will suck your 225 AH dry. I wouldn't count on it running more than 24 hours before SOC drops by 100 AH or to 40-50%.

2*100W solar could, under ideal conditions, contribute 50 AH during the same period. So your bank would drop to about 70% in one day. Under less than ideal conditions solar won't contribute much, so the bank will still drop to 50-60% in one day.
TXcampingfamily
Explorer
Jul 31, 2014
This couple might have the type of panels you are talking about. They posted information on their website. If it's not the same brand maybe it can just give you some more ideas or information.
westend
Explorer
Jul 30, 2014
Harvey51 wrote:
I ordered the Renogy 100 watt kit on Amazon. Ditto on the real world recommendation - it means a lot. I have a metal roof and will have trouble convincing myself to drill holes in it, though I'm sure a bit of caulking will keep them dry. I'm thinking about where to run the wires, too. How about winter - cover it or take it off?
Where are you house batteries located? You can run the wiring from the roof down a sewage vent or fridge vent if that's adjacent to your battery location. Otherwise, i would use a box or fitting on the roof and seal it appropriately.
No need to store the panel in Winter. Mine makes it through MN winters fine, tilted. I like the idea that it is always keeping the batteries in good shape all year long.
Harvey51
Explorer
Jul 30, 2014
I ordered the Renogy 100 watt kit on Amazon. Ditto on the real world recommendation - it means a lot. I have a metal roof and will have trouble convincing myself to drill holes in it, though I'm sure a bit of caulking will keep them dry. I'm thinking about where to run the wires, too. How about winter - cover it or take it off?
dapperdan
Explorer
Jul 27, 2014
PSW wrote:
dapperdan, we will always get a lot of opinions on these forums and that is a good thing. All I can say is that the Renogy systems worked well for me, 200 watts monocrystaline does all I need a solar system to do for me (keep my batteries up for boondocking) and I believe in the old KISS (Keep it simple, stupid) system for myself, since I may well qualify for the final S. Also, I have no intention on keeping my RV for thirty years (I would be a hundred years old) so I plan accordingly. AND, being cheap, I don't like to spend a lot when a little suffices. So, I am a happy little Okie.

Paul

Thanks for the reassurance Paul, I've been looking at Renogy systems/kits for a few days now and it's really reassuring to hear from somebody in the real world using the system and happy with it. Like you, I don't want to over think the whole project but I don't want to waste money either.

My goal is to try and keep our 2 6 volt batteries close to full while parked at our storage lot (with no electricity). We have a residential fridge which, with an inverter will run a couple of days on our batteries or so the salesman said. I just want to be able to fire up the fridge before loading it up for a trip and NOT discharge the batteries too much, my thought is a couple of 100 watt panels will do the trick.

A month or so ago I turned on the fridge before a weekend trip and didn't realize the batteries were already low (60%) and ran the batteries down to where the inverter kicked off, NOT good!! We have a EU3000i Honda but I got to thinking there's got to be a better way. That's when the solar idea entered my mind. LOL

Dan
PSW
Explorer
Jul 27, 2014
dapperdan, we will always get a lot of opinions on these forums and that is a good thing. All I can say is that the Renogy systems worked well for me, 200 watts monocrystaline does all I need a solar system to do for me (keep my batteries up for boondocking) and I believe in the old KISS (Keep it simple, stupid) system for myself, since I may well qualify for the final S. Also, I have no intention on keeping my RV for thirty years (I would be a hundred years old) so I plan accordingly. AND, being cheap, I don't like to spend a lot when a little suffices. So, I am a happy little Okie.

Paul
dapperdan
Explorer
Jul 27, 2014
PSW wrote:
I am going to install a 100 watt Renogy flexible solar panel to the top of my 2350 Phoenix Cruiser. It will supplement the existing 100 watt regular Renogy panel I installed earlier this year. The 100 watt does an OK job keeping the batteries charged when boondocking, but I need just "a wee bit more" power as Scottie used to say on Startrek.

This panel only weighs about four pounds and is 42" by 21" by about an eighth of an inch thick. Here it is:

http://www.amazon.com/Renogy%C2%AE-Monocrystalline-Bendable-Solar-Panel/dp/B00IK19VF6/ref=sr_1_1?ie=UTF8&qid=1404922295&sr=8-1&keywords=renogy+flexible+solar+panel

My question is this: what should I use to fasten this on the roof with?
On the first panel I installed, I made struts, used Z mounts, drilled into the roof and sealed all the mounting with Dicor. Since this one is light and flexible, it can be mounted directly flat on the roof and I don't know whether to use 3M tape, stick it down with DICOR or use some kind of exterior construction glue. Any comments or suggestions would be great. The diameter of the small grommets on the panel would only allow for using a screw of about 3/16" diameter if I drilled into the roof, which I would really like to avoid, so I would like just to stick it on there using something.

Thoughts?

PSW

This topic REALLY interests me as I'm right now researching supplementing our RV with a little solar as well. Everything I read so far, and I'm in NO WAY an expert says to be careful to let the solar panels "breath" a bit as temperature has an effect on performance. Performance seems to be subjective though, wire size, length of run, solar controller style and size of battery bank all play a roll in performance. If it works for you and your situation then all is good I guess.

After reading this thread I'm pretty sure I'm going to go with at least 2 100 watt panels, I thought about just one but especially after reading your dilemma 2 maybe even 3 might be in order.

There's a lot to consider huh? BTW I'm glad to hear your experience has been positive, makes me even more excited to get going on my solar "project"!

Dan

Dan
Almot
Explorer III
Jul 26, 2014
PSW wrote:
what should I use to fasten this on the roof with?

What the roof is made of? if it's thin metal or fiberglass like on motorhomes, then 3M VHB "might" work but only if it's perfectly flat. I would still consider 4 anchor screws, one at each corner.
PSW wrote:
On the first panel I installed, I made struts, used Z mounts,

It's better to use L-mounts, with bolts into the panel sides. But with your particular panel this could be a challenge.

PSW wrote:
Since this one is light and flexible, it can be mounted directly flat on the roof

I'm not sure about that. Panel needs some space underneath for heat dissipation.

PSW wrote:
The diameter of the small grommets on the panel would only allow for using a screw of about 3/16" diameter

You don't need screws larger than #10, and you can drill your own holes for #10 where you want them.

PSW wrote:
This panel only weighs about four pounds

Because it has no glass. Monocrystalline cells are covered in clear plastic instead. I would be skeptical as to long-term performance, i.e. scratches and other things affecting transparency.

PSW wrote:
Some have been critical of the charge controller, but all I know is it works for me and can easily accomodate several of these panels.

Probably a separate topic, just wanted to note that there is more to controller than its ability to accommodate several panels. Adjustable setpoints and remote temperature compensation are very important.

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