Foretravel Owners' Forum

...do you have to find the frame work in the roof to be able to attach the panels and stuff?

I have read so many articles on adding solar that I am totally confused.

So I will see if this is simple way of doing it

I am looking at amsloar's 50A system and was wondering if there is room on the roof for up to 4 170w panels and still be able to move around up there on my 36' coach.

I would guess this is enough to keep my batteries up and on sunny days with the sun over head even run some of the systems.  If I did 4 panels that would give me a max of 680w but I realize getting the full amount is probably not a reality.

What is the roof construction is there plywood under the fiberglass or do you have to find the frame work in the roof to be able to attach the panels and stuff?

Currently I have 2 house batteries and 2 red top starter batteries, but I do have another rack where I could add a 3rd house battery.

If I add solar for charging the batteries I found a place to store my coach about 2 miles from my house instead of 40 miles for the same price.

Do some research into panel sizes, 170 watt is pretty small today. You might be able to fit larger 300+ watt panels.

Some members swear by using adhesive to stick the panel brackets on the roof.  Others like to use screws into either the fiberglass or the steel roof frame members.
AM Solar uses glue-on brackets for the installations they do in their shop.  We had ours done there in Sept of 2015 with glued-on brackets.  Have had zero failure of anything they installed in the 4 years since.

40' U320, eight 180 watt panels. I can walk (very carefully) from rear ladder to front with some careful step arounds.

Yes it is but you willneed supports to hold them at an angle. Easy tomake them.
JohnH

I wondered about the size but I thought the more watts the larger the panel?

Thanks, all my appliances are still gas so that may be a bit more than what I need but you never know, more is better :-)  how many watts are your panels.

If the batteries are at float does the system just shut off incoming power?

I am probably to clumsy to have that many. "LOL"

True, but it not proportional eg: 340 watt panel approx 78X39. 170 watt panel approx. 58X26. First time I bought panels, made a template out of cardboard and tried it on different spot on the roof to see where they could fit. You will also see the price per watt normally goes way down with bigger panels.
Bigger panels often mean higher voltage which means smaller wiring down to controller.
Been using uni-strut  and VHB tape for many years with no problems.

Steve, for the level of effort and $ put on as many high wattage panels that you can.  I have 4 300 watt full sized commercial panels, non-tilting with custom brackets that match the curve of the roof stuck on with 3M VHB tape.  This is a project many can do themselves.  I can get to everything on the roof that might need it.  I would suggest finding a panel that you think will work and make a cardboard cutout the same size, maybe several, and see how they will fit on your roof.  Your rear roof rack is a limiting feature there but you can work around it or remove it.

We can get more than 6KWh on a good summer day (about twice what we use).  Mid winter gloom, low sun angles maybe 2KWh.  It is sort of a best fit.  You want enough to fully recharge your batteries every day.  Adding another battery with the same use reduces the depth of discharge on each battery and increases their life. If you are lucky, very limited generator time. Send a PM if I can help more.

I put 4 285 watt panels (330 watts today) on our 36 foot roof. I screwed them down, some into the aluminum supports, some into the glass/wood. The roof is .400" thick, a think layer of FG and then the rest is wood. There were already at least a couple hundred screws into the roof so I added about 40 more. No problems or leaks in over 10 years. I have not touched anything since I installed it.
If you have a drill press, saw and just a little talent, make your own mounts. Just do a neat job without cables looking like a San Francisco trolly.
See my old list of materials, sources from years ago. Don't tilt the panels unless you are clever. If you try and get up on the roof to tilt them, you WILL fall off sooner or later and probably end your RV life.
Pierce

Eight 180 watt panels, 1440 watts total.
  36' coach I would probably do no more then 6 180 watts.  Less if only for storage purposes.  With the right solar controller it will taper down then shut off charging as needed for long battery life.

Thanks, I really dont want to burn up my batteries, I am not sure how old they are but so far they seem to be holding up OK.

Does not matter how much solar you have, a good solar controller will shut off, and not overcharge your batteries. If you read the forum, you will see many have gone to residential fridges. If you do that down the road, you will be happy with the extra charging ability.

You need to spend several days reading all you can online and don't be in a hurry.  Don't try and reinvent the wheel and learn from others mistakes. I like commercial panels as they are built like tanks. 39 inches wide and about 77 inches long with a 1 1/2" thick aluminum frame. About 52 lbs so they will take a lot of abuse from trees, wires, etc. Most will be 36 volts so four panels in a series parallel wiring with bring about 72 volts in only four wires down to the the controller. Could do all parallel and have more wires coming down. All series would bring 144 volts in only two wires but on a cold morning, the voltage would exceed 150 volts and is discouraged by controller manufacturers as well as giving a possible fatal shock to the installer or during maintenance. Figure about 1 1/2" clearance between the bottom of the panel and the roof at the lowest point on a curved roof or 1 1/2" under a flat roof like ours.

96" coaches need more planning as the 3 inches on each side make a difference.

A good MPPT controller will get about 2/3 of the potential wattage from the panels in summer.

Our coach with LED lighting and 4K TV never needs the generator with less than 500ah house battery bank. Propane fridge and no AC.

Pierce

I fit six 320 watt panels on my 34 ft U270.
Lessons learned:
1. Get Sunpower panels, model X22 370 watt panels are the most durable and efficient (22%), and well worth the cost.
2. Don't bother tilting them. Just add more panels.
3. I used VHB tape and aluminum brackets, which is working well after 2 years of outdoor use and 16,000 miles.
4. Leave at least 4 inches above roof. This aids in cooling and allows cleaning.
5. The panels can stick out over the side of the rig up to the mirrors. I did this and they cleared every obstacle.
6. Install as many panels as you can fit. On cloudy days, power is reduced by up to 90%, so you'll be glad you have the power.

I used 4- 300watt panels like Rogers, they are on one charge controller. I then saw I had more room and bought 2- 360watt LG panels and have them on there own controller.
I glued 2"x3" aluminum rectangular bars (5200 sealant) and then installed 3 hinges on a side of all the panels. They are now able to raise. With limiting cables on each they can be tilted forward past 90 degrees and left that way so I have almost total room to walk the roof to perform any maintenance. 3- 300 watt panels are tied together and lift as a unit on the drivers side. 3 panels monted on the passenger side each lift separately. They can be tilted from the ground using a pole to lift each of them and latching them into position.
The 3 panels tied together lift with a 12v scissor jack mounted in the middle of the 3. The jack has a wired hand controller and a wireless controller so they can be lifted from the ground also.
With the hinge mounts the panels are easy to remove if needed, just pound the hinge pin out and the panel is free to come off.

Last month I mixed two LG 335 with two LG 280 watt panels on my roof.  Now, I have 1187 watts, up from previous 560 watts.  63.8 Volts times 18.61 amps, equals 1187.31 watts.
I am using 4 LG panels with two 280 w panels installed two years ago at one end, (the front,) wired in series, and at the rear of the roof, two LG 335 w panels wired in series, both groups to combiner box on roof in parallel (so, 63.8 volts to controller) and down refrig vent to single mppt charge controller rated at 1400 watts at 12 volts. 150 volts/100 amps.
I choose one solar controller over two separate controllers because of reduced cost and the fact I could then use all the existing wiring without any additional wiring.  By doubling the voltage down the refrig opening, existing wire was fine.  Two controllers would have only yielded  43 more watts on the roof, 1230 vs 1182 watts.
The math was as follows.  Max power of 335 watt panels 34.1 (max power volt, VMPP) x 2 = 68.2 V x 9.83 (max power current, MPP) = 770 watts.  LG 280 31.9 volt x 2 = 63.8 v x 8.78 = 560 watts.  In parallel 63.8 volts (lower of two parallel voltages) x 18.61 amps (combined amps) = 1187.31 watts from my roof system.
Mounting hardware, wire, and combiner box were all from AM Solarin Springfield, Oregon.

There is no such thing as a "modified sine wave inverter." How can you modify a sine wave? It's nothing more than a &#@! advertising term when it should be called a modified square wave inverter.
Pierce

Roger, is 150/185 a typo?

I noticed the heat strips not heat pumps. Second or third time I have seen heat strips on nice coaches/rv's recently
  Victron are 5k watts 24/48 volt.
2 batteries?

I noticed the heat strips not heat pumps. Second or third time I have seen heat strips on nice coaches/rv's recently

Victron are 5k watts 24/48 volts max?

2 batteries?

Their published technical chart shows 85% at 3000 watts.  Two units would put the efficiency well Into the mid 90% range using two inverters at 1500 watts each.

The Victron marketing people sent me a link to their 24/48 volt chart when I asked for the 12 volt chart.

Asked them again. We will see.  Just want the facts, mam