Community Forums

haveaday · 03-04-2023, 09:31 AM

Hi,

I'm planning on adding a fair amount of solar to my coach. I'm going to need four runs of 6 AWG from the roof to the battery bay. Does anyone have any experience with the best path from the roof down to the storage bays? I believe my coach was pre-wired for solar, though that would only be a single run and not sufficient for my plans. I also haven't located either end of that wiring yet.

Ben

richpatty · 03-05-2023, 06:37 AM

If you have a solar prep, there will be a metal plate on the roof. If there is, take off the plate and you will need to cut a hole to reach the wire ends below that point. I used an oscillating saw. The wires should terminate in the bay next to your battery bay.

Wondering…why do you think you need 4 wiring runs? If you put them in parallel, or at least a Parallel/series combination, you can do far less wires. I only have one run for my 1440 watts.

If you need to pull a run, many folks use one of the vent pipes to bring down the lines to the basement.

Hope this helps.

haveaday · 03-05-2023, 06:41 AM

Thank you Rich, that does help.

Your question about why I need multiple runs is a good and reasonable one. I'm planning on installing 8 450 watt panels. I'm not going to be able to bring all 8 panels down on a single run, so I need to add a run or two no matter what. As long as I am, for issues of efficiency, shade tolerance, and the cost of larger MPPT controllers, it makes sense to pair them up and run them that way.

-Ben

richpatty · 03-05-2023, 06:54 AM

Quote:

Originally Posted by haveaday

Thank you Rich, that does help.

Your question about why I need multiple runs is a good and reasonable one. I'm planning on installing 8 450 watt panels. I'm not going to be able to bring all 8 panels down on a single run, so I need to add a run or two no matter what. As long as I am, for issues of efficiency, shade tolerance, and the cost of larger MPPT controllers, it makes sense to pair them up and run them that way.

-Ben

Ok…that is a lot of solar! So I can see the need for additional runs. Keep us posted on your progress. Not sure I know anyone with that much solar….have you mapped it out on the roof?

Rich

haveaday · 03-05-2023, 07:04 AM

Quote:

Originally Posted by richpatty

Ok…that is a lot of solar! So I can see the need for additional runs. Keep us posted on your progress. Not sure I know anyone with that much solar….have you mapped it out on the roof?

Rich

I've got it roughly laid out. I don't see a problem with real estate, but the placement of cross bars, etc might be a little challenging. I'm planning on running two of the ACs from a 48v battery bank and inverters.

-Ben

haveaday · 03-28-2023, 09:51 AM

It turns out that despite a solar prep sticker on my control panel area, the build sheet for my coach suggests the coach wasn't ordered with solar prep. So, it looks like I'm on my own for all of my runs. Right now, I'm favoring bringing the solar cabling down the rear cap, to the frame rails and then forward. That all looks pretty straightforward, except the top section of the rear cap isn't visible from the engine compartment. I looked in the bathroom to see if I could tell what was in that space, but didn't have any luck there either.

Does anyone know of any access to that portion of the rear cap? Is it just a free air area I can run through? Do I need to go back to the drawing board?

-Ben

AlanTerry · 03-28-2023, 09:57 AM

Look at the cabinets you might find two cabinets with a spacer between. That could be a chase you can use that’s what I did, although a different Rv than yours. Good luck.

MarkS · 09-07-2023, 12:22 PM

Rich, I'm planning on installing solar in my 2021 DSDP w/ solar prep. I am wondering if you have experience in finding the solar prep wires on the roof. I'm seeing elsewhere that you remove the metal cover plate and cut the fiberglass under the plate, but people are claiming the wires are not necessarily under the cover plate location and can be a bear to locate. Any tips or recommendations you can share would be helpful! Thanks! Also, any suggestions for how to cut the fiberglass? I don't want to accidentally hit something located directly under my cut. Do you recommend using a cutting wheel instead of a jig saw or hole saw? Thanks!

richpatty · 09-07-2023, 01:10 PM

Quote:

Originally Posted by MarkS

Rich, I'm planning on installing solar in my 2021 DSDP w/ solar prep. I am wondering if you have experience in finding the solar prep wires on the roof. I'm seeing elsewhere that you remove the metal cover plate and cut the fiberglass under the plate, but people are claiming the wires are not necessarily under the cover plate location and can be a bear to locate. Any tips or recommendations you can share would be helpful! Thanks! Also, any suggestions for how to cut the fiberglass? I don't want to accidentally hit something located directly under my cut. Do you recommend using a cutting wheel instead of a jig saw or hole saw? Thanks!

Hi, I have the same pre-wire and was a to find it under the plate. I was new to Newmar and was surprised to find that they don’t cut the hole for you! :-). I was lucky and once I cut through the fiberglass, the wires were pretty much right there…. For cutting, I used a oscillating saw which allowed me to control how deep the cut went. It also allowed me to cut a larger, square hole. And also helps if you need to cut more. A hole saw is a bit harder for that. It worked really well for me.
There shouldn’t be too much right under there except the wires and insulation so as long as you don’t go too deep, you should be ok.

rfg9585 · 09-07-2023, 01:33 PM

Ben,

I have 1350watts solar and make a single run down the fridge vent into the bay where my inverter is located. This is also where I put a board that I pre-configured with all my new components. Included here were several breakers and buss bars to accommodate all the incoming old\new wires.

Here's my install thread.....near the end you can see the components laid out.
https://www.irv2.com/forums/f56/fina...ll-517637.html

MarkS · 09-07-2023, 02:23 PM

Thanks Rich!
I've just studied the details of your install while reading Charlie's original thread. Nice work.

May I please ask you some additional questions:

1) Any recommendations for the junction box on the roof? Did you use AMSolar's Roof C Box? Or something with Zamp or MC4 connectors?

2) I see that you used a series/parallel configuration, with only 2 panels in series x 4 sets in parallel. Any reason why you didn't go with 4 panels in series x 2 sets in parallel? From looking at the specs of the charge controller, it looks as if it can handle the higher voltage. And the higher voltage would yield less voltage drop in the wire run to the basement.

Thanks!
Mark

Dutch Star Don · 09-07-2023, 03:36 PM

On most newer Dutch Stars, if you drop the plastic beauty cover on the kitchen Fantastic Fan, you can see into the roof cavity and the solar prep wires are just to the rear of the fan. This way you can guarantee that they're present.

"haveaday".....You might look at coming through the rear cap near the air scoop on the corner of the roof and run the wiring down beside it.

richpatty · 09-07-2023, 05:07 PM

Quote:

Originally Posted by MarkS

Thanks Rich!
I've just studied the details of your install while reading Charlie's original thread. Nice work.

May I please ask you some additional questions:

1) Any recommendations for the junction box on the roof? Did you use AMSolar's Roof C Box? Or something with Zamp or MC4 connectors?

2) I see that you used a series/parallel configuration, with only 2 panels in series x 4 sets in parallel. Any reason why you didn't go with 4 panels in series x 2 sets in parallel? From looking at the specs of the charge controller, it looks as if it can handle the higher voltage. And the higher voltage would yield less voltage drop in the wire run to the basement.

Thanks!
Mark

Hi Mark,

I did use the combiner box from AMSolar. It worked fine as it allowed me to feed the lines into the box and wire them into their screw junctions. Been working great since installation.

As far as the parallel vs serial, you have to decide the pluses and minuses. I went with 4 pairs as when you start putting them in series, if one of the panels gets shaded, it effects its mates, so you don’t want too many in series.
And parallel requires more connection runs back to the connector box…so maybe more work. Also as you chain parallel together, the amps go up and that can be a problem depending on the gauge of wire you have. So going 2 in series with 4 parallel pairs comes down in the middle of those two downsides. I have lower amperage (higher voltage) which is a benefit of series, but have some risk of any one panel getting shaded affecting it’s pair.

Hope this helps.
Rich

Gregs4018 · 09-12-2023, 12:40 AM

With the right Charger/Controller you can still use the 6 guage wire Newmar installed with no problem. I typically can do 10-12 370 watt panels in series on 10 AWG PV wire at an average of 38 volts DC per panel atc10 Amps. So that's 400Volts DC nominal in series at 10 Amps. Remember to add the rated voltage of each panel in series to pick the right charger/controller. As far as shading dropping string voltage, it is pretty minimal. The newer panels all have bypass diodes minimizing shading drop from one panel to another. If you are really concerned about that you can always add a Tigo Optimizer TR4-A-O for $40-50 per panel for improved isolation and optimization. The may get you 5% or so improvement.