Solar Panel Cabling

Cabling for our Solar Panels

When we purchased our Catalina 34 in 2015, it had solar panels mounted on top of the cockpit Bimini, the wire from the panels were ran down the Radar Mounting Pole and into a 'hole' in the combing that was closed off with a healthy glob of Silicone caulking.  Our updated Solar panel system deserves better.

Our plan is to run the cables (4)from the solar panels (2) via a conduit that has a waterproof connection to the combing.

Step 1. Remove the existing cable clamshell at the Combing.

The clamshell was secured to a fitting plate with 3 screws and that plate was screwed to the combing with another 4 screws and a - once was rubber - seal, now long deteriorated.

The solar wires pass through a poorly drilled out not circular hole.

The new Conduit requires a minimum of 1 5/16" hole, but the locknut on the fitting works with a max hole size of 1½" 

The existing wires from the Solar Panels are 6AWG, so I have ordered 30' of both Red & Black 6AWG tinned copper fine stranded wire and appropriate ring terminals - they should arrive today ( 8/15/2026)

Ok, perhaps tomorrow! 

The new conduit is already on the boat ready for installation, as are the end connectors.

I have helped several other sailboat owners install there solar systems, and the conduit works out really well.

Step 2. Run all of the solar panel cables from the Combing, through the Conduit 90º Elbow and conduit up to the area below the panels. Terminate them inside a waterproof box that will be mounted on the side of the Aluminum 4040 Solar Panel mounting frame.

Secure the Conduit to the side of the Radar Mounting Pole with heavy duty ties, then along the support brace from the Pole to the Panel mounting frame.

 I'll connect the Conduit to one end of the box and then add 4 cable glands for the 4 wires from the panels. Inside the box I'll install this terminal block in order to connect the solar panels and the 6AWG wires that are in the Conduit.

So that should be a neat installation.

Step 3.  Run the wires from the conduit connection inside of the combing, forwards inside the Cockpit Port Side Locker along the existing wire loom. Then through the bulkhead into the Head compartment behind the cabinets, through the forward bulkhead separating the head and the Nav table, and then down to the new MPPT & Breaker.

Step 5. Test the new panel:- Open the breaker for the Aft Panel supply, Close the breaker for the Fwd Panel supply. Check the Victron Display and the VRM for the data from the new panel.

Easy.  ( Ok, it's a boat! ) Close the Aft Panel Breaker and we should see the increase in solar power generation, assuming our batteries need it. I'll turn on the water heater for a few minutes, that should demand more solar power.

So, that's the plan, all of the bits should arrive in the next few days and some I already have on the boat. We'll plan to go down on Tuesday to do the work if the bits arrive.

Ok, today's update.

The terminal block inside the connection box is completely wired. The 4 wires from the conduit are installed with 6AWG Ring Terminals and the 4 wires from the solar panels are connected installed with 10awg Ring terminals, both have heat shrink covering the part of the ring terminals not touching the terminal studs. Box closed.

Down in the cabin, turning on the 'Fwd Breaker' then waking up the Victron Display, it shows that we're getting solar power, only 120W but that's probably because all of my tools for the job are still sitting on top of the panel. Stowing the tools and we're up to 240W better but considering the blue sky and the Sun overhead, not ideal. Probably due to the dirt on the panel. The water at the dock is turned off right now so we'll clean the panels on Monday.

Meanwhile --- I pull out more of the Port Side Cockpit locker contents, mostly spare lines and shore power cables then adjust my belt for doing Boat Yoga and reach into the locker up towards the combing where the conduit elbow enters. I had threaded all of the wires for the panels through the ring that secures the elbow on the inside of the combing during the install, so that would not be an issue. However! I could not get the ring on the threaded portion of the elbow. Just not quite enough thread on the end of the elbow extends from the inside of the combing to allow getting the ring in place.

Having lost a few pints of fluid during all of today's activities, I decided to take a break till Monday, closed up the boat and headed home. Good news - The water is back on at the dock.

Later in the day, my good buddy Mike, visited for some adjustment to his new Victron Bus Bar, it needed drilling out. While in the shop wagging our tongues, I showed the issue I had with the Conduit elbow using the spare parts I have in the shop. He suggested I use a thinner -O- ring. Duh! Great idea Mike! I can remove the -O- ring and use Butyl tape, that should allow the thread to protrude nearly another 1/8" inside the Combing. Duh! I'm pretty confident that will work. But just incase, instead of cutting out the -O- ring on the outside, I'll pass it in through the hole and the threaded ring so that if I have to take a different approach at least the -O- ring will be intact and in position.

So, the plan on Monday is to use that method to fix the conduit elbow in place then I'll thread the new solar panels wires through the bulkhead into the bathroom behind the cabinets, then into the main cabin above the Nav table and finally down between the liner and the hull and into the area beneath the Nav table. There they will connect to the MPPT Aft disconnect switch and then to the MPPT controller.

During all of this, we had the solar panels off line for about 72 hours and we used the AC to cool the boat for about 8 hours. Our Battery Bank was down to 43%. I think that is the lowest they have ever been since installation 3 years ago.  Even though we only have one panel connected right now, they are charging. It's partially cloudy down at the boat ( at least, according to our Victron Remote Monitoring system data ) but we're getting ~ 200 + watts of solar right now. That's a good sign.

Ok, time for a review.

Remember, this is South Florida, despite that we're suffering from a drought right now, that doesn't mean that it does not rain! And it does not mean we're clear blue skies all day long. The Victron system shows the weather as either Cloudy or Sunshine - not much in between. So it's not easy to tell from the data that the boat is getting max solar.

However. 

Solar Production over past 7 days ( < 8/27/2026 )

From the data graph above, we've had a max of 252 Watts production during the past 5 days and then today, after the second panel and mttp were connected, 494 Watts. That's from 640Watts of panels. So not the max but it never is.

All of the cabling is now complete although the cable management under the Nav Table leaves a lot to be desired - it's not neat and tidy. 

So I'm going to call this project complete. I'll take some pics and show them in another post.

We're gearing up for a long Labor Day trip to Lake Worth next weekend, sailing from Port Everglades up to Lake Worth Inlet, then hopping down the ICW on Sunday/Monday. It will be a good shake down cruise and we will definitely need the AC overnights.

So, see you on the water.

Paul