Anyone made there own combiner box if so how and what did you use. Am solar has one for $80 but I am sure it can be built for a lot less.

Thus is what I am going to do. Combiner box

Calkidd wrote:Thus is what I am going to do. Combiner boxPretty much what I did. I did use pre-made electrical ground bars I got from Lowes. I glued a PVC divider between the hot side and the ground side, used waterproof cable connectors where the panel wires come in and my heavy weight down wires to my controller leave from the bottom of the box with a conduit connector and a conduit going all the way down to the RV basement. I also bring each pair of panel wires (six 140W panels) into the box individually and connect them to the bus bars with a mini fuse in the + side. This allows me to connect or drop off individual panels without having loose hot wire ends touching things they shouldn't. Also makes troubleshooting individual panel output easy.

That's what I used. I could have went a little bigger, it was tight w/ 3 panels and the buss bars.

$6 4x4 PVC weather junction proof box from Home Depot. Comes with a rubber gasket. The sun will do a number on it. Should last some years, depending on the area.AM Solar have a J-box that mounts on the side of fridge vent, $60. It's "supposed" to go under the vent hood, but on finished installs I see the soft hood plastic bulging a little there.

Almot wrote:$6 4x4 PVC weather junction proof box from Home Depot. Comes with a rubber gasket. The sun will do a number on it. Should last some years, depending on the area....Used one of those. Painted it white to help against the UV.

Solar combiner box | Good Sam Community

45 Replies

Colo_Native
Explorer
May 02, 2016

This is what I made up still need to paint it.
Colo_Native
Explorer
May 02, 2016
Calkidd wrote:
I took what I originally posted here and did a little modification. Instead of an electrical box I used a junction box and drilled my own holes to best suit my needs.

That is what I ended up doing as well the only thing I did was add a piece of plastic between the bus bars just in case they broke loose. I plan on painting it to help with the sun issues. If I could figure out how to post pics I will.
Orcadrvr
Explorer
May 02, 2016
Calkidd wrote:
I took what I originally posted here and did a little modification. Instead of an electrical box I used a junction box and drilled my own holes to best suit my needs.

Nice Job!
grizzzman
Explorer
May 02, 2016
Calkidd wrote:
I don't see a reason for a fuse at the box. Unless there is something I am not aware of. I have a 50 amp circuit breaker between the panels and the controller.

The 50 amp breaker will do nothing for a panel failure or a wire short for that matter. Do you REALLY believe a 30 amp source would EVER trip a 50 amp breaker? I agree that you need a switch there and it will serve OK for that. Electricity will ALWAYS take the path of least resistance. If a panel short's out ALL of the 28 amps will go to that panel. Even if it doesn't start a fire, melted EVA could cost you a new membrane roof. I would also rather have 3/4 of a array then NO array while camping. But other then that I see no reason to fuse there. :R
Calkidd
Explorer
May 02, 2016
I don't see a reason for a fuse at the box. Unless there is something I am not aware of. I have a 50 amp circuit breaker between the panels and the controller.
grizzzman
Explorer
May 02, 2016
Calkidd wrote:
I took what I originally posted here and did a little modification. Instead of an electrical box I used a junction box and drilled my own holes to best suit my needs.

Nice work. I have that box and buss bar out in the garage. Have you decided not to fuse at the box?
Calkidd
Explorer
May 02, 2016
I took what I originally posted here and did a little modification. Instead of an electrical box I used a junction box and drilled my own holes to best suit my needs.
pigman1
Explorer
Apr 30, 2016
Calkidd wrote:
2ga? Seems excessive. Are you running 200+ amps from your panels?
Excessively long run to the charger and battery bank and I was looking to keep line losses to the absolute minimum. Perhaps a bit of overkill, but the additional cost was well within my budget. Don't use the overall current capacity of the wires, calculate the actual percent line losses based on distance and max current carried. I was shooting for approximately 2% line loss. A good line loss calculator
Colo_Native
Explorer
Apr 30, 2016
I found a place online to buy sunlight resistant wire
http://www.wireandcabletogo.com/XLP-USE-2-RHH-RHW-2/
rocmoc
Explorer
Apr 30, 2016
Colo Native wrote:
Should I run 10 awg wire from the box down to the controller or bigger can't find uv protected wire in larger sizes

I used #4 as recommended by HandyBob's Solar site, https://handybobsolar.wordpress.com/rv-solar-quick-answer/ and ran the wire enclosed in Conduit. Easy purchase at any local electrical supply.

What is critical is the length of the wire from the junction box to the controller. Longer the run heavier the wire. All explained on Bob's site.

rocmoc n AZ/Fld/Baja