Solar Panels

Dennyha said:

If you add solar panels to your roof, I recommend a junction box on the roof. A heavy gauge wire connects the bus bars in the junction box to the solar controller (separated by a circuit breaker). You can then easily add panels in the future, by connecting them to the bus bars in the junction box, if you feel you need more solar watts, or if your needs change in the future. All wiring from the roof line down should never need to change if the project is planned right from the start.

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Any chance you have a picture of your junction box setup? Sounds like a great idea.

I'll be using a generic, plastic conduit box with 4 holes and a gasketed lid from the local hardware store.... a few members have posted pics and has sold me to do the same.

Dennyha said:

If you add solar panels to your roof, I recommend a junction box on the roof. A heavy gauge wire connects the bus bars in the junction box to the solar controller (separated by a circuit breaker). You can then easily add panels in the future, by connecting them to the bus bars in the junction box, if you feel you need more solar watts, or if your needs change in the future. All wiring from the roof line down should never need to change if the project is planned right from the start.

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Thanks for the advice Denny. Just this past weekend I was talking to Jim (Oregon Camper) about my desire to add a panel. I too was thinking to use a j-box on the roof "in-case" I wanted to add more panels later. If I do anything, I will make sure I use a proper conductor size from the combiner box to the controller.

Unsure exactly where I'd bring my leads down in this front bath model but pretty sure I won't use a tank vent stack.

jbeletti said:

Thanks for the advice Denny. Just this past weekend I was talking to Jim (Oregon Camper) about my desire to add a panel. I too was thinking to use a j-box on the roof "in-case" I wanted to add more panels later. If I do anything, I will make sure I use a proper conductor size from the combiner box to the controller.

Unsure exactly where I'd bring my leads down in this front bath model but pretty sure I won't use a tank vent stack.

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I think we got distracted and didn't finish that conversation. I question why you are hesitant to come down the vent stack. It is 100% dry and protected. Just measure the distance down where you want to pull the cables out and put some tape on them at that distance (so you know when to stop feeding wire down). Drill access hole...pull wires out...seal hole.

This is a fairly standard method, with RV's that have the refrigerator in the slide out. (as you can easily go down the frig vent in those)

Oregon_Camper said:

Any chance you have a picture of your junction box setup? Sounds like a great idea.

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As LBR noted above, I also used a generic junction box from Home Depot. Inside, I used JB Weld to attach a positive and a negative bus bar. After attaching 4ga wires to the bus bars, and running the wire through the roof line into the basement, I used non-leveling Dicor to seal the j-box to the roof. I then ran the solar panel wires through conduit. The conduit attached to the j-box with water tight fittings, and I sealed the other end of the conduit with silicone caulking. If I were going to do it again, I would opt to use the combiner box sold by AM Solar. It is pricey, but fabricating one from scratch was a bit of a struggle, and I'm tight on space inside the j-box. Their combiner box has more room, and working with 4ga and 10ga wire takes some room to manipulate the wires.

I did create a thread to detail my project. I did start with 200 watts on the roof, then added 200 more watts, and then added 200 more watts. At 600 watts, I think I'm good for the way I use the system.