Solar panels

Topic: Solar panels (Read 1387 times) previous topic - next topic

Solar panels

June 23, 2011, 06:44:20 pm

We just finished our solar project. 730 watts with 6 panels, all mounted in forward of our front roof air. Three rows of two panels fastened to roof beams with panels mounted parallel to the side of our motorhome. Morningstar 60-amp MPPT controller mounted on bay wall with 50-amp breakers on solar in and battery out.

I expect to get about 50-60% of 730 watts in most of the country as we do not tilt or rotate panels and we are in hot weather. Solar do not reach their rated output when panels are hot. They love cold days and depleted batteries.

Barry & Cindy

Re: Solar panels

Reply #1 – June 23, 2011, 07:21:51 pm

Barry,
Could you post some pics. of your mounting hardware? We have been looking at doing the same thing and haven't found mounting hardware that seems well built.
Thanks

Re: Solar panels

Reply #2 – June 23, 2011, 08:48:22 pm

wow!

Re: Solar panels

Reply #3 – June 23, 2011, 10:32:33 pm

As I posted earlier we have started into the solar world and will have 600 watts on the roof(4x 150 watts). The panels are fastened on first with 3m double sided tape (the best there is) then the mounting brackets are edged with the levelling caulk. We also have the Morningstar controller and also another one by Tri-metric that shows me at a glance the charge coming in and state of charge of Batteries. I had them all put on by AM Solar in Springfield Oregon and they did a nice neat wiring job. With the 3 new AGM Lifestyle batteries, now I have put on a Power Pulse electronic controller to stop sulfation, hopefully all will work as planned. I made deflecters for the leading edge of the Panels so wind etc will be deflected over them while travelling. The panels can be tilted if needed.

Re: Solar panels

Reply #4 – June 24, 2011, 03:35:55 pm

We have been using solar panels for over 10 years and all panels have been installed the same way.

Even though no-hole adhesive mounting is quite popular and recommended by AM-Solar, we choose to use positive screw attached brackets. Adhesive mounts are glued very securely to roof surface which can be a layer of paint or gel-coat. Paint is only a skin on underlying roof and gelcoat is somewhat better attached. Adhesive mounts will not separate from paint, but there is nothing to assure that paint will not separate from its underlying surface.

It is recommended to not drill new mounting holes in solar panel frame. And these solar panel frame holes usually do not align with side-to-side metal roof supports. We are using panels that are about 2' x 5' and we align two panels end-to-end with about 2" open space where the ends are near each other.

We bolt 1-1/4" aluminum angles under the panel's long sides. The longest angle readily available is 8', so we add about 2'. The two panels are lifted to the roof and mounted on one 10' x 2' frame. We then use another 8' + 2' 1-1/4" angle that is bolted to the solar angle and then screwed down into roof metal side-to-side roof supports. Later if we want to lift panels up, we remove bolts holding angles to each other. One angle stays screwed to roof and the other angle stays bolted to solar panels.

We find roof supports with an electronic metal detector that locates edges and center of each roof support.

Using aluminum angles adds cost and prevents air movement from sides and is more than what is required. But I have not found a method that bolts to solar mounting holes and roof supports and offers security at driving 65 MPH in 40 MPH winds and can be easily unbolted from roof.

We tried to install an air deflector on the front edge, but found it prevented air flow under panel from that direction. Solar likes the cooling effect of air movement under panels to help lower temps.

Barry & Cindy

Re: Solar panels

Reply #5 – June 24, 2011, 06:47:30 pm

You neglected to mention that you did all of this work in the Foretravel parking lot in temps that where close to 100°F! Dori and I watched in the relative comfort of our coach as both of you slowly roasted in the Texas sun day after day. Having seen Berry & Cindy's work first hand, I have to say that if they were to open a shop, I'd be the first customer!

Glad everything is up and working and you are getting your expected results.

I'll also mention that Barry & Cindy are 2 of the nicest people you will every meet. If you see Homer in a campground be sure to go up and introduce yourself. You won't reget it.

Re: Solar panels

Reply #6 – June 24, 2011, 07:40:42 pm

Barry,
That seems like a very good way to attach to roof. Lots better than using a uni-strut frame that we were looking at.Thanks for the info.

Re: Solar panels

Reply #7 – June 24, 2011, 10:20:32 pm

I will take a few photos soon of our mounts. Barry & Cindy

Re: Solar panels

Reply #8 – June 25, 2011, 12:10:58 am

Quote from: Barry & Cindy – June 23, 2011, 06:44:20 pm

I expect to get about 50-60% of 730 watts in most of the country as we do not tilt or rotate panels and we are in hot weather. Solar do not reach their rated output when panels are hot. They love cold days and depleted batteries.

Barry - What was your decision factor for not using tilt capability?

Re: Solar panels

Reply #9 – June 25, 2011, 10:29:46 am

Quote

[RE: What was your decision factor for not using tilt capability?]

Eleven years ago we bought two 2' x 5' Siemens 100-watt solar panels ($475 each). (And a SolarBoost-2000 controller) Using angle mounts, I built the ability to tilt in all four directions. Tilting works because when the sun is low in the sky, it can hit the panels closer to 90 degrees, which generates more electricity.

But the sun moves about from one side of the coach to the other side during the day, so we found our panels not optimally tilted all the time. Sometimes the panels were tilted away from the sun.

We considered adding a turntable to be able to rotate the tilt-frame to match the sun's movements in the sky. When we dry-camped in the southwest, we saw lots of home-made designs, some with automated motorized rotation that tracked the sun. And we saw a rope hanging down that was used to pull the panels around. There are a few stories of pivots failing when driving down the road. We never built rotation capability for our panels.

It did not take long for me to realize that most of the time we did not take the time to tilt and our tilt-bars were just sitting the bay. We figured that by not tilting we were only getting 50% of rated output, so nine years ago we bought two more panels (Kyocera-120 $539 each). I figured we now have 100% of our original two panels without having to get up on the roof at every stop. And we could park in any direction again.

FYI, five year ago Kyocera replaced our KC-120 at no cost for KC-130 during a recall. This month we added two Kyocera-135 panels ($388 each), for a total of six panels. We installed a Morningstar TS-MPPT-60 controller and a double-50-amp breaker box. Solar panel cost have come down.

Panels have #10 electric wires connected to an AM-Solar combiner-box mounted on the roof. Cable from roof to bay-mounted controller is #6. Combiner-box makes for a very clean install and easy diagnosis of problems. Also pairs of panels can easily be wired in series for a 24-volt system.

Re: Solar panels

Reply #10 – June 25, 2011, 05:35:59 pm

Photos of Barry & Cindy's solar panels. . .

Re: Solar panels

Reply #11 – June 25, 2011, 05:44:30 pm

That is a really slick looking setup. It brings up two questions. Would more clearance between the coach roof and the bottom of the panels allow better air flow and therefore cooling? And, you said you used fairly large wire from the panels to the controller and I presume from the controller to the house batteries. Where an how did you run the wiring? Where is your battery compartment related to your charge controller.

Re: Solar panels

Reply #12 – June 25, 2011, 06:15:04 pm

Interesting!. Mine are mounted with the brackets on the ends, in the middle of the coach. Then the cables drop down the reefer vent. The controller is mounted in the forward wall of the reefer. Then a cable runs directly to the battery bank (about 15 feet).

Well done install!

Re: Solar panels

Reply #13 – June 25, 2011, 06:17:19 pm

Dave, how heavy are your cables from the panels to the controller and from the controller to the batteries?

Re: Solar panels

Reply #14 – June 25, 2011, 08:13:50 pm

10 gauge. My system doesn't exceed 9 amps. I'm running about 180W.

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Reply #15 – June 26, 2011, 12:14:05 am

Our solar panels have #10 (30-amp) wires to a roof mounted junction box.. From junction box #6 (50-amp) wires go through roof to behind TV to vertical wire channel behind driver's chair through floor to big bay where controller is mounted. Controller to battery is also #6 wires. All wires are type THNN. Roof wires are run in 1/2" LiquidTight flexible non-metallic conduit. Every effort is made to keep conduit for hitting roof when driving Wires and conduit from Lowe's by-the-foot.

Our batteries are in the bay forward of big bay. It is easy to run wires within bay area in our coach. Every coach is different.

The more air flow there is under solar panels, the better chance panels being cooler, which is a good thing. Since panels are mainly used when parked, the air flow will have to come from wind.

Barry & Cindy

Re: Solar panels

Reply #16 – June 26, 2011, 09:41:07 am

I'm feeling a wave of technological lust and envy when I look at Barry and Cindy's solar install. Clean, clean clean.

Chuck

Re: Solar panels

Reply #17 – June 26, 2011, 09:53:10 am

It looks really nice. Congrats on a fine job.

If I have the time and money before I hit the road, would like to do something similar.

Cannot get over how clean and white your roof is!!! I think you did the wise thing bolting down the panels. I wouldn't do it any other way. Adhesive is simply not going to work long term.

Steve

Re: Solar panels

Reply #18 – June 26, 2011, 03:54:28 pm

as for the adhesive and caulf application of panels like I have, I asked AM solar about that and the comment was they would not do it if they had had any problems and they have been in the business for a long time and are well respected in this field. I will let you know in a few years if they have fallen off !! I tried to pull them off a few days later (to test as I was not sure too) but no way Jose did they want to move. The nice part is if you want to reconfigure the layout at any time they can be then removed without screwing up the roof. Time will tell.
That's my feeling and I'm sticking to it (pun intended)

Re: Solar panels

Reply #19 – June 26, 2011, 04:46:20 pm

I also asked AM Solar and I see a lot of panels attached like yours John. I have no doubt they will hold up. AM Solar is very reputable, so have no worry. Just a choice on my part. If you have a gelcoat roof like most, gelcoat is very thjick, durable & strong and not easy to pull away from fiberglass. Our roof is now painted with slip resistant additives and I was concerned about how sticking just to paint upper surface would be a good idea.

Re: Solar panels

Reply #20 – June 26, 2011, 04:46:21 pm

Dave Head asked several weeks ago if our new Kyocera solar panels were using MC4 connectors. Solar panels come with junction boxes (J-box) that have conventional screw terminals inside or MC4 connectors which are quick connect plugs on the end of a wire and are designed for mating connectors with other panels and mostly designed for large grid designs. MC4 do not have screw terminal J-boxes and can be harder to use in a motorhome environment. J-boxes are attached to the underside of panels.

AM Solar now has some panels with MC4 connectors and they have instructions on how to cut off the connector plug and splice the panel wire to battery wires.
Our new Kyocera KD135SX-UPU panels have J-boxes which make it easy for me to connect.
Barry & Cindy

Re: Solar panels

Reply #21 – June 27, 2011, 04:41:01 am

Quote from: Barry & Cindy – June 25, 2011, 10:29:46 am

[RE: What was your decision factor for not using tilt capability?]

But the sun moves about from one side of the coach to the other side during the day, so we found our panels not optimally tilted all the time. Sometimes the panels were tilted away from the sun.

Good thought, thanks... I have always been stuck on the picture [limited as it was] of coaches parked out in Quartzite with the RV optimally positioned to make maximum use of the sun's angle. Admittedly a very limited design use of solar panels.

Re: Solar panels

Reply #22 – June 27, 2011, 06:28:16 am

Quote from: John Haygarth – June 26, 2011, 03:54:28 pm

as for the adhesive and caulf application of panels like I have, I asked AM solar about that and the comment was they would not do it if they had had any problems and they have been in the business for a long time and are well respected in this field. I will let you know in a few years if they have fallen off !! I tried to pull them off a few days later (to test as I was not sure too) but no way Jose did they want to move. The nice part is if you want to reconfigure the layout at any time they can be then removed without screwing up the roof. Time will tell.
That's my feeling and I'm sticking to it (pun intended)

I'd be seriously impressed if they stay glued down over time. Think I'll look into it a little more.

So tilting panels vs non-tiltling - is it worth the extra expense and weight?

Steve

Re: Solar panels

Reply #23 – June 27, 2011, 11:13:00 am

The tilting parts are just some stainless brackets that get put in place of the mounting screws/handles, and is a simple job. These allow for the panel to be altered as needed or left in a 50/50 position. If you are parked for a few days or more it might be worth it to do the climb on the roof and adjust, I will find out this winter in Mexico. The cost is minimal and the weight is not even an issue to carry them.

Re: Solar panels

Reply #24 – June 27, 2011, 10:46:53 pm

We've had the AM Solar panels attached with 3M adhesive for four years now with no problems in high wind and desert sun. We use the tilt-up brackets in the winter if we are boondocking for more than a couple of days. Makes about a 40% difference in output, so I do think it's worth it to spend 10 minutes putting them up or down.

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