I'm looking to finally begin my solar install and I'm trying to plan the best route for my solar cables. Batts are on the tongue, front pass through area houses the inverter and is where I will mount the charge controller, fuses etc. I've got a 2017 Salem Hemisphere 312QBUD. My plan is to drill into the front cap from the roof and just drop wires down behind the hollow front cap. There is a 2-3" gap and its the route in from the bottom that the battery wires go to the inverter. I'm curious if anyone has done this routing or is familiar with the front cap and if the air gap behind the cap continues to the roof? I can't seem to get any confirmation from anyone. Anyone tried this route?

Not familiar with your rig, but the norm is to bring rooftop wiring down to charge controller via fridge vent or even grey vent. Then wires go from charge controller forward to the batts. Im not sure I would want to drill into the top then bottom of the cap. Having shorter wire runs is tempting, but using properly sized wires will minimize loss and allow less invasive hole cutting. Hopefully other TT owners will give some advice as my solar was done on a 5er

The front cap area is already accessible from below. Thats how I know its hollow from the bottom. My rig has a residential fridge (no I don't plan to run using solar), so there is no fridge vent. I could use a vent path to the underside of camper, but I'm hoping so see if anyone knows if the front caps remain hollow to the top. I would still have to drill a hole and use a combiner box or glandat the front lip of the rig, but it would provide an unobstructed route to the front pass-through if my presumption is correct. Also, the entire front of my rig is wide open and perfect for panels.

When we had a TT I ran the panel wires in Cord Mate II then in through the floor to the CC to avoid holes in the roof.

I'll will be doing something similar, as going trough the fridge vent is way to much of a detour for my setup.I will be going on the wall and use a "hide wire system", to achieve shortest run as possible.

MPPT controllers don't care about 50-70ft cable run, if you detour through the fridge vent. With PWM this could be a problem, yes.My 2*245W solar in series, #10 cable, goes through the fridge, then behind the cabinets and along the ceiling/wall corner, down to controller which is mounted inside in front bedroom. Don't want to expose +$300 device to elements. I used Wiremold cover to hide the cable on the wall where it was not hidden in cabinets.Battery cables are routed through the floor to Baby breakers box in front storage, then to controller.

Solar cable routing behind front cap | Good Sam Community

18 Replies

TUCQUALA
Explorer
Feb 15, 2018
My son was easily able to run down the front cap of his Wind River. F/glass sticks did the job from the inside connections in the front cabinet.

You could use this for the input on the top of cap, if fits:

https://www.zampsolar.com/solar-ports

Or just for one pair of wires:

https://www.amazon.com/Winegard-CE2000-Cable-Entry-Plate/dp/B009LX1HFO/ref=pd_sim_263_4?_encoding=UTF8&pd_rd_i=B009LX1HFO&pd_rd_r=EA61G4F5RCPCG48VZK98&pd_rd_w=EKdQu&pd_rd_wg=dYIDp&psc=1&refRID=EA61G4F5RCPCG48VZK98

I used the second one, with liberal Dicor and have no leaks!!!
Almot
Explorer III
Feb 15, 2018
CA Traveler wrote:
But no need for unnecessary losses either. I have 61' of 10 gauge wire at 92V and 8.2A for 0.5% loss. And with flat mounted panels the maximum amps and loss is less.

Why didn't you install 8 gauge MC4 wire then, to reduce unnecessary losses :) ?

But, thanks for illustrating my point. People trying to make the shortest run possible no matter what, sometimes don't do their math.
With 24V panels in series, losses up to 70ft are negligible. If this makes for easier or more aesthetically pleasing install, it makes sense.
epfd217
Explorer
Feb 15, 2018
Thank you for all the great suggestions. I'll have to make a trip to the rv to check that front cap. I have a lightweight, non-metallic probe I never considered using. If that doesn't get me where I want to be, I guess a fish tape is in order.

As I've said, I still plan on drilling a hole, I was just hoping to do it through the front cap instead of going into the rig and then creating a route through the interior. I prefer making one hole over two (or more) new holes. It sucks how much the electrical is hidden in the newer rigs. SO little room to work and even less room to expand or reconfigure devices.
CA_Traveler
Explorer III
Feb 14, 2018
One of the biggest taboos on these boards is drilling a hole in the roof. Many roofs have hundreds of holes from the factory. Secure the wire, seal it correctly and it won't leak. For my roof I don't spare the Dicor and it doesn't leak - if you've every gotten Dicor on your hands you'll understand.
CA_Traveler
Explorer III
Feb 14, 2018
Almot wrote:
RasMouSein wrote:
The MPPT don't care, you don't care...

THINK. Then - post.

At 65V*8A, V drop results in less than 1.5% drop at max wattage, at this length.

Less than 1% loss in daily harvest, or ~1AH out of 140-160 AH (max wattage is only a part of the day, if at all).

You may run #8 MC4 to cut loses lower yet, but I didn't find this necessary.
But no need for unnecessary losses either. I have 61' of 10 gauge wire at 92V and 8.2A for 0.5% loss. And with flat mounted panels the maximum amps and loss is less.
CA_Traveler
Explorer III
Feb 14, 2018
MrWizard wrote:
goto harbor freight or home depot or lowes etc..

buy a fish tape, that thing we electricians use to pull wire

push it in the hollow from the bottom and see how far you can extend it

if it goes all the way and bumps up against the roof, you are good

it it only goes part way and stops, then you know to find another way

the thing is very handy tool to have around and NOT expensive
Plus if there are any light switches, lights, etc on the inside wall pull them and use the hole for probing.

I use a 1/8" flexible fiberglass wire puller that also serves me well for probing. I also have a 4' long flexible drill bit that has served me well. No exposed wires covered or not for me.
fpresto
Explorer
Feb 14, 2018
I agree with Mr. Wizard. Verify that the gap goes all the way to the roof with no ribs in the way. If it is open then your idea should work perfectly.
MrWizard
Moderator
Feb 14, 2018
goto harbor freight or home depot or lowes etc..

buy a fish tape, that thing we electricians use to pull wire

push it in the hollow from the bottom and see how far you can extend it

if it goes all the way and bumps up against the roof, you are good

it it only goes part way and stops, then you know to find another way

the thing is very handy tool to have around and NOT expensive
RasMouSein
Explorer
Feb 14, 2018

THINK. Then - post.

Hehe that's why you had to edit your post...
grizzzman
Explorer
Feb 14, 2018
epfd217 wrote:
The front cap area is already accessible from below. Thats how I know its hollow from the bottom.

My rig has a residential fridge (no I don't plan to run using solar), so there is no fridge vent. I could use a vent path to the underside of camper, but I'm hoping so see if anyone knows if the front caps remain hollow to the top.

I would still have to drill a hole and use a combiner box or glandat the front lip of the rig, but it would provide an unobstructed route to the front pass-through if my presumption is correct. Also, the entire front of my rig is wide open and perfect for panels.

I don't know if this helps but I ran 4 6awg wires down the awning mount then to the pass through.
Find some bailing wire , drill a small hole and see if it goes through.

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Solar cable routing behind front cap

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