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Solar panel mounting orientation?

I know this all depends on how I'm parked in orientation to the sun so I'm asking for your experiences and how your panels are mounted.
I have 4 100 watt solar panels that I'll be installing on my 36' FT.  I made a tilting mount system that will have 4 legs/panel mounted to the roof with VHB tape + 1 screw and covered with polyurethane caulk.  I plan to wire these up with 2 in series then both sets in parallel with an mppt controller.
The front air conditioner is about mid way on the coach length.  In the very front of the roof I have an old in-motion sat. dish that doesn't work and I'll remove.  There is also the tv antenna.  I don't want to move the tv antenna so will have to be aware of shading when it's raised.
My tilt mount is designed so that the panels will tilt along the long axis.  I'm planning to mount the panels perpendicular to the length of the coach so that the high side will be at the middle of the coach's roof and I can tilt them by climbing on the roof rather than using a ladder.
Is there any preference in which side to mount them so that the low side is either on the passenger's side or driver's side?
If I mount them on the passenger's side I shouldn't have any shading from the tv antenna, or minimal.
Thanks!
Forest & Cindy Olivier
1987 log cabin
2011 Roadtrek C210P
no longer 1999 36' U320 build #5522
2013 Rzr 570 & 2018 Ranger XP1000
2006 Lexus GX470
2011 Tahoe LT 4x4
Previous 1998 45' 2 slide Newell, 1993 39' Newell

Re: Solar panel mounting orientation?

Reply #1 –
Quote from: folivier –
I know this all depends on how I'm parked in orientation to the sun so I'm asking for your experiences and how your panels are mounted.

Is there any preference in which side to mount them so that the low side is either on the passenger's side or driver's side?
If I mount them on the passenger's side I shouldn't have any shading from the tv antenna, or minimal.

I know this may sound strange but if you have an absorption fridge I would mount them on the opposite side as the fridge. The reason is this will put the fridge on the shaded side in relation to the panels. This will help with the efficiency of the fridge while dry camping.

Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Solar panel mounting orientation?

Reply #2 –
There are many others who have solar that will explain why they all seem parallel to the length. Maybe just choice or possibly aero issues while traveling. Information which may influence my install.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Solar panel mounting orientation?

Reply #3 –
I installed all four in the direction of travel. The commercial panels are too long to mount in any other configuration. They are fixed and cannot be tilted. With an RV fridge, I could not see any reason to tilt as they keep our batteries charged with float occurring before noon even in winter. While I do climb up on the roof for maintenance, I am very careful as the panels don't leave much room for walking. The idea of regularly climbing up to tilt them as we move from campground to campground in all weather conditions seems very chancy to me.

We have a large HDTV and use the micro and latte machine everyday without ever starting the generator.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Solar panel mounting orientation?

Reply #4 –
We have 6 x 160 panels.  Mounting "length-wise" parallel to center line of coach was only way to get them all to fit AND allow a safe walking path down the center of the roof, which was one of my personal requirements.  Our panels can tilt up to either side, using simple prop rods.

IF you run your panels parallel to center line, and IF your tilting device can only tilt one direction, then one consideration would be how you would rather orient your coach.  To get maximum solar exposure, you will want your coach parked in a generally east-west direction.  If you park facing east, you will have the morning sun coming through your front window, and afternoon sun on the rear of the coach.  If you park facing west, then the morning sun is on the rear end, and afternoon sun is on your front window.  The shady (cooler) side of the coach in the afternoon would also be a factor to think about, but your big awning can supply shade parked in either direction.

All else being equal, we prefer parking with front of coach facing east.  We have a residential fridge, so Mike's logic (above) does not apply to us.

Others will chime in with stuff I didn't even think about, I'm sure.

1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Solar panel mounting orientation?

Reply #5 –
Here are mine .. 300w each

VHB tape only no issues

Re: Solar panel mounting orientation?

Reply #6 –
Based on the fact that most, if not all, of our boondocking is done in the summer, my main concerns were getting the proper side up, access getting around the panels (4), and having them stay put out of the wind preferably. During the summer the sun is usually overhead so flat works. When the sun isn't overhead, tilting  usually isn't effective because we are parked in the woods, under those tall woody things with green stuff on the ends of their appendages that tend to reduce the efficiency of solar panels.
Now, down south is a different story. In the winter we do like to hook up to a pedestal so we can use our electric heater, our microwave, our TV(s), etc. The solar panels are then just along for the ride and to charge the house battery while we are parked somewhere without hookups.
Trying to make a single tilting scenario mandates always satisfying the original coach orientation. Not always possible.
Our orientation is three perpendicular to the coach axis and one parallel to the coach axis.  The three are mounted on a "self-designed" rack right behind the kitchen fan roof exhaust hood, I can remove two bolts and then tile the rack up for cleaning or max gain. The single panel (again, a self-designed rack) is mounted just to the rear of the King Sat dish. My racks raise the working top surface of the panels about 4" off the roof of the coach.
Works for us. Find a design that works for you. I'm 76 and don't care to go up on the roof to adjust panel angles for efficiency anymore.
Good batteries, clean tight connections, LEDs wherever possible, conscientious conservation practices, and you will be fine.

Nitehawk,  Demolition Lady, & our NEW master, Zippy the speeding BB cat.
1989 Grand Villa 36' ORED
Oshkosh chassis, 8.2 DD V8
2006 Saturn Vue AWD

Re: Solar panel mounting orientation?

Reply #7 –
VHB tape on unistrut to roof, mechanical fasteners for panel to unistrut.  Not adjustable so I try to fit as many panels as practical, to make up for it.
Jim C.
coachfree, previous 1997, 1999, 2000, and 2003 Foretravels.

Re: Solar panel mounting orientation?

Reply #8 –
As has been said before, rather than climb up and tilt them just install another panel to compensate. Panels on right side, fridge on left, all is good with the world! Remember to park facing east
Larry
1996 U295 36'
Build # 4805
Actually we sold it but just like to lurk

Re: Solar panel mounting orientation?

Reply #9 –
Here are photos of our installation:
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Solar panel mounting orientation?

Reply #10 –
We are researching solar panels and are curious about the flexible (thin) panels that are lighter weight and conform to the shape of the roof.  The downside is that they are not as efficient, from what I've read.  I would be interested in knowing about real life experience from those that have gone this route. 
2000 U320 mid entry  #5688
2006 Jeep Liberty


USMCR retired
SDFD retired
FEMA US&R TF8

Re: Solar panel mounting orientation?

Reply #11 –
Quote from: Sven and Kristi –
We are researching solar panels and are curious about the flexible (thin) panels that are lighter weight and conform to the shape of the roof.  The downside is that they are not as efficient, from what I've read.  I would be interested in knowing about real life experience from those that have gone this route. 


Flexible Solar Panel | Renogy Solar
Had 12 100 watt panels on my 99, easy to install [VHB tape on each corner] , lots of wiring [had to run series/parallel],  not as much heat transfer to roof as I expected, lightweight and because of smaller size, easy to use space on roof you could not with big panels,  but expensive, well over twice the price per watt.
Had them on about a year before I sold the coach in 2015, and the plastic coating on the panels were starting to cloud and yellow. Did not really check if this decreased output, but if they have not improved the quality substantially, would not go that route again.
Jim C.
coachfree, previous 1997, 1999, 2000, and 2003 Foretravels.

Re: Solar panel mounting orientation?

Reply #12 –
I have three, 300 watt panels (soon to be four) all oriented front to rear.  Mine are positioned for accessability to roof top equipment.  There will be two side by side between the air horns on the front, one in the center in front of the rear AC and one in the rear to the drivers side of the centerline.

I thought about being able to tilt my panels but after watching an old guy with a Bluebird coach struggle with his I figured not getting on the roof and risking falling off the roof twice for every time we stop wasn't worth it.  In practice with no tilt and no particular attention to orientation and clouds and trees and all else we have no problem getting to float on almost any day.  I am adding a fourth panel because I gave one and eapecially in the winter months the extra watts will be welcome on some days.

I went all parallel wiring.  Wire size or cost was not a factor.  Reliability, performance with variable shade and having no combiner boxes or anything extra on the roof seemed to work best for me.  There are lots of opinions about wiring.  Choose the way that works best for you.

I had my sheetmetal guy make two piece mounts that fit the curve of the roof anywhere you put them.  12" long x 2" wide. One on each corner of the panel oriented front to rear.  The part that the panel attaches to lets you set the vertical offset, about 2" seems good and the taller roof piece gives you a side to side panel locator.  I used 5/16" ss bolts and nylock nuts and VHB tape.  The aluminium mounts, nuts and bolts and VHB tape added up to about $13 per corner.  He can make more.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Solar panel mounting orientation?

Reply #13 –
I recommend:

1. No tilt
You will get too tired tilting the panels all the time.
Too complex. Simplicity will ensure long life.
Your panels will endure 100MPH winds. Think of a tractor trailer passing you in the opposite direction. Keep them hard-tied to the roof. I used VHB tape and it's holding up fine.
Allow at least 4 inches of clearance above the roof. The 4 inches allows for maintenance and provides good cooling in scorching summer temperatures.

2. Allow maintenance pathway
I oriented my panels both ways and it does not make a difference in performance, However, providing a maintenance pathway will yield safer and practical maintenance of roof components.

3. Add another 100 Watt panel
This will make up for the loss of not tilting. No fuss.
While you're at it, install as much solar as you can afford. With our 1920 watt system, we still have to run the generator in the cold winter and on cloudy, rainy days or while under a lot of shade.

See my Foretravel U270 solar panel installation video at  Tim's RV Tips #1 - RV Solar Panel 48 Volt Lithium Installation, January 5,...
1997 U270 34FT Build 5140 Cummins 8.3 Allison 3060R
Solar 1920Watts, 14KWH lithium. Orion BMS.

Re: Solar panel mounting orientation?

Reply #14 –
1st pic is seven 180 watt panels. Last pic is one more 180 watt panel added at front passenger side.  Hard to tell from photo, but there is a safe walking path from ladder to front of coach with a couple of side angle steps across the panels. 

AM solar equipment and mounts.
Dan - Full timing since 2009
2003 U320 40' Tag 2 slide

Re: Solar panel mounting orientation?

Reply #15 –
Here is a photo of the non-skid maintenance pathway on my roof.
1997 U270 34FT Build 5140 Cummins 8.3 Allison 3060R
Solar 1920Watts, 14KWH lithium. Orion BMS.

Re: Solar panel mounting orientation?

Reply #16 –
Tried to stay away from equip shadows.  LG panels. AM solar wire and vent combiner box.
97 U295 40, Build #5040, 6C8.3 325 HP
Oregon Continuous Traveler
Samsung Residential #RF20HFENBSR,
Xantrex SW2012, (3)AGM8D Hse, (2)AGM Grp24 Eng, Victron BMV-712, 1800w Solar 4 LG & 2 Sunpower
Extreme Full Body Pt w/hdlmps, new furn/floor, 4 down Lexus 2004 GX470 AWD curb weight 4,740 lbs
Prev: 1990 Barth, 10L 300 2 yrs; 91&92 Monaco Signature, 10 yrs, 10L C 300 &  6C8.3 300; 1997 ForeT 6C8.3 325 since May 2017.  Employed by Guaranty RV 14+ yrs.  Former VW New Car Dlr/Service Dlr, Sales Mgr, Rv Sales, and Service Adviser from 1968-2017
"Don't criticize what you can't understand" Bob Dylan

Re: Solar panel mounting orientation?

Reply #17 –
Other than the crank-up OTA antenna, the sun has to be quite low towards the horizon for anything else on the roof to throw a shadow on solar panels.
Check your angle necessary to "throw" a shadow on the closest panel sometime. Then do the math.
Nitehawk,  Demolition Lady, & our NEW master, Zippy the speeding BB cat.
1989 Grand Villa 36' ORED
Oshkosh chassis, 8.2 DD V8
2006 Saturn Vue AWD