Running new wiring for a solar setup

[NickinCO]

I have the factory 300w solar but the more I look at it the more I’m unimpressed with their wiring. With potentially adding an extra 600w of solar on the roof in spring I’m considering a second full system. It looks like I could cleanly run wires into the existing vent hole by replacing the vent in the curb side front compartment where the batteries are stored. See attached picture. This would allow for the shortest possible cable run and I think I can route them clean enough to not look terrible (up the front corner of the trailer). Thoughts? I’d swap to Victron controllers for both setups so they communicate and provide the same charge profile.

[howson]

Thoughts?

Not ideal IMHO. The "gotcha" with solar controllers (in particular Victron) is they start providing solar power (PV) only after the output of the panels is 5v above the battery's voltage. That means if a Battle Born is at 13.0v, a solar panel must exceed 18 volts to generate an output from the controller.

The advantage of tying all the panels together (in a series-parallel configuration) is the PV output typically exceeds the battery voltage earlier in the morning. With two setups, both sets of panels must overcome the PV limitation. Of course this is highly dependent on the panels used, etc.

It's a long read, but there's a lot of these "lessons learned" sprinkled in my install thread (I usually post as I go, warts and all). If you haven't had a chance to check it out, consider slogging through it as there just might be something that saves you time and $$. https://gdrvowners.com/forum/solar/1...n-2019-315rlts

Howard

[NickinCO]

The single factory 300w Jamboni panel has a vmp of 32 volts so that shouldn’t be an issue? this will be connected to a Victron 100/30. I’m in Colorado with excellent sun 99% of the time.

The other setup will likely be 4 180w panels with two panels in series and then paralleled connected to a Victron 100/50.

[howson]

The single factory 300w Jamboni panel has a vmp of 32 volts so that shouldn’t be an issue? this will be connected to a Victron 100/30. I’m in Colorado with excellent sun 99% of the time.

The other setup will likely be 4 180w panels with two panels in series and then paralleled connected to a Victron 100/50.

That could work.

I don't know this for a fact so it would take some sharp-pencil work on your part, but if you sold the Jaboni (and it's controller) could you then install six of the 180W panels and run just one Victron controller? One set of wires, one cut off, one circuit breaker...(it all adds up). Even if it meant replacing the OEM wires from the roof, at least you'd be using the existing path. Use an AMSolar junction box on the roof and it's really not that hard to put it all together.

Just my .02 and meant as "food for thought". What you're contemplating isn't "wrong" to the best of my knowledge.

Look forward to reading your future posts as you work through the upgrade.

[NickinCO]

That could work.

I don't know this for a fact so it would take some sharp-pencil work on your part, but if you sold the Jaboni (and it's controller) could you then install six of the 180W panels and run just one Victron controller? One set of wires, one cut off, one circuit breaker...(it all adds up). Even if it meant replacing the OEM wires from the roof, at least you'd be using the existing path. Use an AMSolar junction box on the roof and it's really not that hard to put it all together.

Just my .02 and meant as "food for thought". What you're contemplating isn't "wrong" to the best of my knowledge.

Look forward to reading your future posts as you work through the upgrade.

I hear ya, it would definitely be cleaner to do one system. The problem with the stock setup is best I can tell from where the panel is mounted and the cables enter the trailer (at the rear curb side), there’s at least 35’ of 10awg wire each way to get to the charge controller. Trying to replace that much cable seems like a monster headache,
and equally expensive (0 awg wire?! for 70’?) I’m considering even putting another hole in the side of the trailer near the roof for the wire to enter since I’m sure that vent is there for a reason. The roof directly above that cabinet is part of the front shell and I’m not sure it can be drilled? Going rearward would put me in the shower.

[acoleman43]

I hear ya, it would definitely be cleaner to do one system. The problem with the stock setup is best I can tell from where the panel is mounted and the cables enter the trailer (at the rear curb side), there’s at least 35’ of 10awg wire each way to get to the charge controller. Trying to replace that much cable seems like a monster headache,
and equally expensive (0 awg wire?! for 70’?) I’m considering even putting another hole in the side of the trailer near the roof for the wire to enter since I’m sure that vent is there for a reason. The roof directly above that cabinet is part of the front shell and I’m not sure it can be drilled? Going rearward would put me in the shower.

That's my issue as well. The existing wire goes through the roof trusses. To replace the factory wire you will have to drop the ceiling, install new wire, then reinstall the ceiling. To be honest, this might just be the easiest way to do it...no new holes in the roof for the wiring. Once the ceiling is dropped you can run all your wiring from the panels to the front storage area. You can even run your wires from the storage area to the control center......Either way it's a huge pain.

[NickinCO]

That's my issue as well. The existing wire goes through the roof trusses. To replace the factory wire you will have to drop the ceiling, install new wire, then reinstall the ceiling. To be honest, this might just be the easiest way to do it...no new holes in the roof for the wiring. Once the ceiling is dropped you can run all your wiring from the panels to the front storage area. You can even run your wires from the storage area to the control center......Either way it's a huge pain.

I dunno, that doesn’t fix the issue that a wire run that long just isn’t ideal. There’s so much room at the front of the trailer for solar it just boggles my mind how the factory thought the placement they use is “good”. At this point I’d rather drill another hole in the roof than pull down ceiling panels.

[Jimmer]

That's my issue as well. The existing wire goes through the roof trusses. To replace the factory wire you will have to drop the ceiling, install new wire, then reinstall the ceiling. To be honest, this might just be the easiest way to do it...no new holes in the roof for the wiring. Once the ceiling is dropped you can run all your wiring from the panels to the front storage area. You can even run your wires from the storage area to the control center......Either way it's a huge pain.

My 2021 Reflection 315RLTS came with solar prep which was just a set of 10 gauge wires running into the RV from the roof. I went with a new new entrance and combiner box on the roof, as shown in the pictures. It really was pretty easy, and the important part was not drilling through the AC ceiling duct. I came in through a closet, and no one will every see the entrance hole in the ceiling, unless they open the closet and look up.

Note that howson wrote "Use an AMSolar junction box on the roof and it's really not that hard to put it all together." Unfortunately, for a bunch of solar panels, you need to buy an additional bus bar for the AMSolar combiner box, and they no longer sell this additional bus bar due to Covid shortages. I spoke to them on the phone 2 or 3 weeks ago, and they said that they have a very limited supply of the second bus bar, and they are using that supply for their own installs, and they could not sell me what was needed. So, I used eBay and Amazon to make my own combiner box, as shown in the pictures.

[acoleman43]

NickinCO the box is about 21' long and the drop would be about 8' to 9'. about 30' total run for wires using the stock "hole". I've also considered a new junction box closer to the front but will still require either dropping part of the ceiling or adding some type of trim to hide the wiring into the storage area. One though was to place the new junction box next to the black tank vent. The wiring can go down, alongside the vent pipe (the small angle wall behind the toilet), then go under the trailer into the storage area. Because I want my GX Touch in the control center, I will have to run wiring from the storage area to the control center area so dropping the coroplast may be an easier way to go.

Jimmer there's no real closet in the 21G that's accessible from the roof. The only closet is under the front cap. I like your install, very clean and easy.

[howson]

Note that howson wrote "Use an AMSolar junction box on the roof and it's really not that hard to put it all together." Unfortunately, for a bunch of solar panels, you need to buy an additional bus bar for the AMSolar combiner box, and they no longer sell this additional bus bar due to Covid shortages. I spoke to them on the phone 2 or 3 weeks ago, and they said that they have a very limited supply of the second bus bar, and they are using that supply for their own installs, and they could not sell me what was needed.

Additional bus bar? What I referenced is AMSolar's C-Box that can handle up to 10 inputs from panels. If panels are wired in pairs (series-parallel), theoretically that means up to 20 panels could be be wired through this one box. That's a lot of panels!

What I was suggesting is removing the OEM junction on the roof of the OP's trailer and replacing it with the AMSolar box. One set of wires going from the roof to one solar controller. One type of panel so they all work together without any issue.

By chance are we not writing about the same bus bar/component? What I'm referencing is at https://amsolar.com/rv-combiner-box/20-roof and shown below.


Howard

[Jimmer]

Additional bus bar? What I referenced is AMSolar's C-Box that can handle up to 10 inputs from panels. If panels are wired in pairs (series-parallel), theoretically that means up to 20 panels could be be wired through this one box. That's a lot of panels!
...
By chance are we not writing about the same bus bar/component? What I'm referencing is at https://amsolar.com/rv-combiner-box/20-roof and shown below.


Howard

The AM Solar combiner can accommodate 4 bus bars (as shown in your picture), but only comes with 2 (as shown in my picture in this post). I thought I would need 2 bus bars for the positive and 2 bus bars for the negative in order to have what is shown in your picture, so I would have to purchase 2 additional bus bars. I now see I was wrong, as each bus bar can secure 10 wires, as you have pointed out. My error for not reading carefully enough. However, I'm happy with my solution which, although it wasn't needed, will allow me to connect 7 strings of two panels each and have a bit more room in the box for the wires.

[NickinCO]

NickinCO the box is about 21' long and the drop would be about 8' to 9'. about 30' total run for wires using the stock "hole". I've also considered a new junction box closer to the front but will still require either dropping part of the ceiling or adding some type of trim to hide the wiring into the storage area. One though was to place the new junction box next to the black tank vent. The wiring can go down, alongside the vent pipe (the small angle wall behind the toilet), then go under the trailer into the storage area. Because I want my GX Touch in the control center, I will have to run wiring from the storage area to the control center area so dropping the coroplast may be an easier way to go.

Jimmer there's no real closet in the 21G that's accessible from the roof. The only closet is under the front cap. I like your install, very clean and easy.

Why not drill through the front cap directly into the closet? I've been reading about drilling through fiberglass, it doesn't seem too terribly difficult? I do need to explore the option with the toilet vent. I've seen YouTube videos of the wire going directly down the vent even.

[Yoda]

I have the factory 300w solar but the more I look at it the more I’m unimpressed with their wiring. With potentially adding an extra 600w of solar on the roof in spring I’m considering a second full system. It looks like I could cleanly run wires into the existing vent hole by replacing the vent in the curb side front compartment where the batteries are stored. See attached picture. This would allow for the shortest possible cable run and I think I can route them clean enough to not look terrible (up the front corner of the trailer). Thoughts? I’d swap to Victron controllers for both setups so they communicate and provide the same charge profile.

Nick
In looking at your floor plan is the black/gray tank vet pipe that goes through the roof accessible in your pass through or somewhere? On my unit the dealer use the space beside it to come down into the trailer. When I did my additional panels I followed the same path.

Just a thought

Keith

Merry Christmas everyone

[acoleman43]

Nick
In looking at your floor plan is the black/gray tank vet pipe that goes through the roof accessible in your pass through or somewhere? On my unit the dealer use the space beside it to come down into the trailer. When I did my additional panels I followed the same path.

Just a thought

Keith

Merry Christmas everyone

See below.







NickinCO I suppose you could drill through the front cap. My preference is to not do that so I'm going to go a different direction.

[Yoda]

See below.







NickinCO I suppose you could drill through the front cap. My preference is to not do that so I'm going to go a different direction.

How is that angled wall in the bath attached. If it can be removed you could run into the belly and forward - a lot shorter distance than the wiring goes now.

Just a thought - they are probably running 10 awg from the existing panels now. You could follow the same route, but go in series on the panels to up the voltage and possible go with 8 awg or 6 awg and the wire would still be flexible enough to run the same route the existing does.

Trying to brainstorm here

Keith

On edit - how did they get the stock wiring to the inverter - through the attic? If so you could use one of the existing wires and pull the new through, but uses a double ended pull rope so you can pull the original wire back.