I am in the process of mounting solar panels on the boat. I have three 85 watt panels, and a single 65 watt. Plan is to mount them with the three 85 watters going through a controller and to the battery switch, so it can be diverted to the start/emergency batt. if it should be necessary.
First, there really should be no need to wire the panels so they can charge the start battery if your setup is properly designed. You would have either an echo charger or battery combiner keep the starting bank topped off whenever there is a charging level voltage on the house bank side of the device.
When at home or anywhere shore power is available, the batt. switch is normally off.
The solar panel outputs should be fused before the input on the solar panel charge controller. This is a good idea if you ever have to work on the charge controller or the solar panel circuits. I solved this problem by running the solar panels into a fuse block. The output from the fuse block goes to the input side of the solar panel controller. A switch on the output of the solar panel controller turns off the panel output as necessary, and allows you to shut the panels off so that the shore-power based battery charger isn't competing against the solar panel output.
The 65 watt panel will go through a seperated controller and direct to the house bank, as bilge pump is wired direct to it. Since I avoid as much as possible any connections/splices, the plan was to hard wire all connections, with soldered splices.
I generally recommend using a good crimp connection with adhesive-lined heat shrink tubing rather than soldering. Again, IMHO, having the panels go through separate charge controllers isn't ideal. However, since the fourth panel is smaller than the other two, it might make more sense to have it connected independently. It should probably be switched, so that it can be shut down when not needed.
Then realized that I live in hurricane alley, and the panels may need to be removed on short notice at any time. So I need to use some type of plug for connections. First thing that comes to mind is a standard plug like on a trailer connector. Possibly with some heat shrink over them of some thing to keep as much moisture out as possible. Any of you electrical gurus have a better suggestion for a plug, that would make a dependable connection and be easily removable. Also any comments on my wiring plans are also welcome.
What I did for my solar panel installation, and I have two 85 watt panels, and a 25 watt "maintenance" panel, is to use the Marinco trolling motor connectors instead.
Photo courtesy of Bass Pro Shops, click to see product page there.
These are polarized three-conductor cables with a water-proof twist-lock connection. What I did with the plugs on my boat was to run three wires to them. One wire is a ground, one goes to the solar panel input fuse block, and the other comes from a 12 VDC switch block. That allows met to use the same type of plug and socket for powering accessories, like my Davis Megalight, or to connect the solar panels to charge the batteries. Since the Davis Megalight is only really useful at night, and the panels are only useful during the day, there isn't really a problem with doing this. This allows me to easily disconnect and stow the panels in the case of heavy weather.
