Forum Discussion

Fubeca's avatar
Fubeca
Explorer
Oct 05, 2014

My solution for a cheap combiner box - roof mounted

So I decided to parallel my panels to allow more flexibility in my campsites due to partial shading.



I wanted a nice combiner box - but couldn't bring myself to spend the money.

I bought a cheap box at Home Depot, and a couple of small buss bars which I attached with JB weld. After a short time on my temporary trailer, I noticed the box lid was slightly deforming.

I decided to put a galvanized cover over the box to ensure I didn't have any issues when it was on the Trailer.

So I found a relatively cheap galvanized roof vent, drilled out the rivets and attached it to the roof above my Cbox with dicor.



Sorry for the poor pictures - all I had was a cell phone.

  • pigman1's avatar
    pigman1
    Explorer
    Oct 05, 2014
    I just use a 6" square PVC box, the small ground bus bars and waterproof fittings to bring 4 panel feeds in. I have the leads fused in the box and my 6ga feed down to the controller comes out of the bottom. I've used the same setup on 2 class A's and never had a problem. Cost less than $20 for everything.

    Do whatever works for your setup. Higher price doesn't mean better.
  • BruceMc's avatar
    BruceMc
    Explorer III
    Oct 05, 2014
    westend wrote:
    BruceMc,
    What type of fitting do you have for the roof entry?


    Similar to this type: (updated - link to pic of metal fitting was broken)



    I mounted it in the hollow aluminum frame rail by drilling into it from the roof, then enlarging the hole with a file. Once large enough, I threaded the fitting into the hole, then removed & added sealant & re-installed it. The result:



    I added additional sealant on the grommet where the wires passed through.
    By having the connector under the panel, it is out of the sun and rain.
  • RoyB's avatar
    RoyB
    Explorer II
    Oct 05, 2014
    I am not much of fan for drilling through the RV ROOF for anything.

    I have used the PVC ELECTRICAL BOXES (LOWES) and drilled a large hole in the center of it. Then I can mount this box to the side wall close to the roof and hopefully come out inside a ceiling mounted cabinet.

    The PVC Electrical box can use a weather tight lid and uses several combinations of PVC TUBING connections into the Electrical box.

    This is great using inside cabinets to go thru the floor also... The Electrical box seals real good using RTV sealant etc...





    Food for thought...
    Roy Ken
  • westend's avatar
    westend
    Explorer
    Oct 05, 2014
    BruceMc,
    What type of fitting do you have for the roof entry?
  • BruceMc's avatar
    BruceMc
    Explorer III
    Oct 05, 2014
    I ran #10 wires into the roof under each panel, then ran them to my connection box next to the charge controller. Therefore I have no visible wires on the roof, and no combiner boxes in the weather.
    Here's a series of pics from my solar install.
  • westend's avatar
    westend
    Explorer
    Oct 05, 2014
    Attaboy!
    You're right, the solar merchants want big money for the combiner boxes and a guy can build one easily. I used a PVC 1 1/2" LB, two buss bars, some HDPE for spacers, epoxy, and an all=weather fitting for the two MC4 cables.

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