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Going to install 2 roof mount solar panels on my 159" WB. Using a combiner box and then having to run the charge wires thru the roof. What is the best way to get this wiring down off the roof to ensure minimal leak chances. Is there an optimal location?
thanks.
 

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Optimal location is the one that provides the shortest run to your charge controller and batteries.

I would place the hole on top of one of the ridges on the roof, minimize chance of water pooling around it.

I went with the AM Solar combiner box (http://www.amsolar.com/home/amr/page_72_16/roof_c-box.html). I sealed around the entry hole with 3M VHB tape, push butyl tape around the wire coming through the hole, and then the design of the box allows you to fill a reservoir around the hole with sealant (Dicor).
 

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Going to install 2 roof mount solar panels on my 159" WB. Using a combiner box and then having to run the charge wires thru the roof. What is the best way to get this wiring down off the roof to ensure minimal leak chances. Is there an optimal location?
thanks.
Hi,
Don't know it its the best way or not, but I brought my PV wire into the backup camera housing at the back -- no holes in the roof.
Some pictures here: http://www.buildagreenrv.com/our-conversion/promaster-diy-camper-van-conversion-electrical-and-solar/our-promaster-van-conversion-solar-panel-mounting/
Down toward the bottom of the page shows the wiring through the camera housing.

If you have not already purchased the PV panels, I'd consider getting one larger panel (you can probably get over 350 watts in one panel these days) -- this would simplify the wiring and eliminate the need for a combiner box on the roof. Not a big deal either way, but something to think about. If you go with one panel, the voltage will be higher which means less voltage drop and smaller wires, but also means you need a charge controller that will handle the higher voltage.


Gary
 

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They are available from many suppliers including
just search "cable entry plate." The problem is many sellers do not list the size and when it comes you might find it is too wide to fit on the raised rib on the roof. I went with a very small waterproof electrical box, cut an opening in its base for a waterproof connector and bought two waterproof grommets for the wire to enter. High bond tape and Dicor Lap Seal are your friends here.
 

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If your charge controller can handle the voltage then run the panels in serial (ie. daisy chain). You will have less voltage drop on your wire and will not need the combiner box. Look up the max open circuit voltage for the panels you're using and double it. If the total is under the maximum input voltage for your charge controller you're good. Mr. Hein used a pretty slick cable boot for the roof entry on his Sprinter:

http://www.mcmaster.com/#7008k84/=1022ej3

http://www.impact3d.com/solar_panel_wire_exit_installed.jpg
 

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Thank you for posting the links to my Sprinter build. The cable entry I used has held up well.

Some notes: It has snap closures on the sides that don't quite hold as well as I wanted so I later coated the whole fitting with Dicor. I spliced the leads coming from the solar panels together into an 8 gauge wire and fed that through the fitting into the van. The strain relief and portion of the wire is wrapped with shrink tube. I bonded a 1/8 thick ABS plate to the roof with VHB tape and then drilled the hole for the fitting.

I think a NEMA box VHB taped to the roof (see RDinNHandAZ photo above) is easier overall. Run the leads from the panels into the sides with grommets (sealed); splice them into a common wire going through a hole in the bottom of the box and roof. Here is a decent box:

http://www.amazon.com/gp/product/B005UPNQM4



Update: We have a new direct mount tower that when used with a Renogy 100 watt panel (also fits other panels) will result in what we think is a nice install on the Promaster roof. These towers mount directly to the panels so there is no need for crossbars. The pads for the tower bond to the roof with 3M VHB tap. Here is a CAD image of the layout.


 

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Hein,
You do fab the best looking stuff! Rock on.
 

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Hi,
Don't know it its the best way or not, but I brought my PV wire into the backup camera housing at the back -- no holes in the roof.
Some pictures here: http://www.buildagreenrv.com/our-conversion/promaster-diy-camper-van-conversion-electrical-and-solar/our-promaster-van-conversion-solar-panel-mounting/
Down toward the bottom of the page shows the wiring through the camera housing.

If you have not already purchased the PV panels, I'd consider getting one larger panel (you can probably get over 350 watts in one panel these days) -- this would simplify the wiring and eliminate the need for a combiner box on the roof. Not a big deal either way, but something to think about. If you go with one panel, the voltage will be higher which means less voltage drop and smaller wires, but also means you need a charge controller that will handle the higher voltage.


Gary
Im having trouble removing the rear camera housing to then run my solar cables through the housing.....the two screws at the back are just spinning , how did you remove the housing ?
 

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Im having trouble removing the rear camera housing to then run my solar cables through the housing.....the two screws at the back are just spinning , how did you remove the housing ?



Hi,
On mine, the two screws come out without a problem and the whole back of the camera housing comes out. The screws are only about half an inch long and screw into two brass looking fittings -- you can just see them in one of the pictures on this page http://www.buildagreenrv.com/our-conversion/promaster-diy-camper-van-conversion-electrical-and-solar/our-promaster-van-conversion-solar-panel-mounting/


I just tried unscrewing them again and they come out fine. Not sure why they would not on yours?


Gary
 

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Hi,
On mine, the two screws come out without a problem and the whole back of the camera housing comes out. The screws are only about half an inch long and screw into two brass looking fittings -- you can just see them in one of the pictures on this page http://www.buildagreenrv.com/our-conversion/promaster-diy-camper-van-conversion-electrical-and-solar/our-promaster-van-conversion-solar-panel-mounting/


I just tried unscrewing them again and they come out fine. Not sure why they would not on yours?


Gary
Thanks ....weird , on mine the whole stem came out , not the short screws , i had to keep spinning the screws with a drill , at same time pulling on the housing until it came off . But see how it is supposed to work now .
 

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My Wire Entry, Backup Camera Housing

Of course the idea came from this forum (GaryBIS). For my setup, imho, this might be the best location for running the solar cable. Backup camera housing was removed (2 screws), disconnected camera (2 screws), and popped out the break light, drilled hole in bottom right of housing at a slight angle and fed the cable through, one connector at a time (Anderson Power Pole). Discovered two small square flaps the other cables run through w/ an "X" cut into the flap and the APP cable went right in. I will add lap sealant (non self-leveling kind) to the hole later today. Only possible hiccup I see is the cable resting in the channel along the back of the van, which I'm sure seeing steady draining during rain; however, the cable does run up and then up again through the housing, which is external to the van. Anyone see any issues w/ this setup?

IMG_8268.JPG IMG_8271.JPG
 

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I'm not sure that you want/need to seal the cable entry since its on the bottom of the housing. When I took mine off to run the wires in, the housing is not sealed completely on the bottom, I assume for drainage. I don't see it in the pictures, but be mindful of rubbing where the wires enter the plastic. I put rubber grommets in the holes, but if your sealant holds the wires in place that shouldn't be a concern.
 
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