Anyone have some pics or links to a DIY solar panel roof mounted combiner box?My solar is acting up and not charging, I think its the quick connects coming off the panels to the main line on the roof. Figure I need to remove the quick connects and either solder the connections or run them into a combiner box. Since I need to mess with the stuff on the roof I might as well add another panel for a total of 3 at 300 watts so 3 lines coming into the main line is probably to much to solder together plus if I need to replace a panel having all 3 connected together would be a pain so I might as well just add a combiner box on the roof.

YoutubeThat's an $8 DIY combiner, just a water proof box and some bus bars. I'm working on a 4 panel system, 2 series into 2 parallel so that one looks like what I need.

You can dispense with a cb by connecting in series.

time2roll wrote:MC4 combiner box:Or go 3:1Thats what I have now on the roof. When you wiggle the connectors I get 14.4 volts when not wiggling them I get 12.3 which is what the battery's are charged to. Kind of think I didn't catch the lack of charge in time and it cost me a battery. Guess there not as water tight as they claim to be.

2oldman wrote:You can dispense with a cb by connecting in series.I guess I need to study up on solar again. Installed my system 4 years ago and after the install I guess I purged the info from my head as I don't remember all the particulars.After a quick refresher reading I want to stick with parallel as most of the time I'm in shady areas. Parallel has been working great for the last few years with just 200 watts on the roof.

Solar combiner box. | Good Sam Community

hedge
Explorer
Oct 18, 2018
Instead of using cable glands, I made my box to accept mc4 connections so the connections themselves became the passthrough to the box and then the panels plug into the box.
grizzzman
Explorer
Oct 17, 2018
grizzzman wrote:
Colo Native wrote:
Made my own

Home Depot? I have 4 panels parreled to that same box
I have 4 more glands due to running two #6 pos and neg.
This allowed me to run them down the awning mount.
grizzzman
Explorer
Oct 17, 2018
Colo Native wrote:
Made my own

Oops double post
Optimistic_Para
Explorer
Oct 17, 2018
Muddydogs wrote:

Thanks for the pic. I'm going this route as well, I have some thick copper and aluminum I can cut down and tap for a couple buss bars. Can't find any waterproof box inlets for the smaller solar cable but I figure I'll get a couple bigger waterproof inlets and just fill the extra space with some caulk once I get it together.

These come in various sizes:

Cable Glands
Muddydogs
Explorer
Oct 17, 2018
Colo Native wrote:
Made my own

Thanks for the pic. I'm going this route as well, I have some thick copper and aluminum I can cut down and tap for a couple buss bars. Can't find any waterproof box inlets for the smaller solar cable but I figure I'll get a couple bigger waterproof inlets and just fill the extra space with some caulk once I get it together.
big_buford
Explorer
Oct 17, 2018
Just cut 2 mc4 connectors out of a buddys system not charging. I would assume all MC4's are not created equal?
Colo_Native
Explorer
Oct 17, 2018
Made my own
mike-uswest
Explorer II
Oct 16, 2018
I have used two of the AM Solar boxes, and they are quick and efficient.

Mike
pauldub
Explorer
Oct 16, 2018
I used one of these.

AM Solar also offers a combiner box that suitable for RVs.
Muddydogs
Explorer
Oct 16, 2018
Spridle wrote:
In your case, a combiner box is nothing more than a water tight box with terminal strips inside. You will have to secure the box to the roof. Assuming you have two panels you will need 6 entry glands to keep the cable entry points water tight. A quality box is expensive.
Combiner Box Hyperlink

You could replace your MC-4 connectors because yours are either damaged, cracked or never tightened and water got inside. MC-4 connectors dont leak if they are not damaged and installed correctly. They are used on every commercial solar installation I have seen. Also tiewrap the connectors so they are not setting on the roof in a puddle of water or snow.
Crimp Tool Hyperlink
and the connectors, get the correct size for your wire gauge.
MC-4 Connectors hyperlink
You should replace your two "Y" combiners, water probably got inside.

I would say the problem is the connectors have set for 3 years in water or snow all winter long as my trailer is stored outside, some years I have a couple feet on the roof almost to the point where I start thinking about removing some. I'm sure the Wyoming wind hasn't helped when towing either.

I'm sure everything was tight when I installed it but who knows now? I haven't checked the connectors myself as it was all we could do to get the smallest guy in hunting camp on the roof when I noticed the problem. Once home I pulled the battery's and put the trailer up for the winter figuring I would deal with it in the spring. I'm just trying to get a plan now, pick up supplies and decide if I want to add one or two more panels to the system.