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Join Date: Oct 2005
Location: In the Woods Pa
Re: 12V Boat Wiring
What other said, but with a little more detail. I'd wire direct to a separate battery for the trolling motor, you must have a fuse or a non-resettable circuit breaker. They make connectors with the CB/fuse built in. You might want to get a connector close to the motor so you can either remove the battery for charging by unplugging or get access to the batter through the connector for charging in the boat. You should use #6 wires at least for the motor. Try to use few connections/splices in the wire they cause voltage drops, heat-up and limit your top speed while using energy from your battery. Fuse should be about 25% higher than your motor running current (about 30-40 amps, check your motor specs). If the motor run is long, over 12 feet, go up in wire size. Use marine wire, so any gas in the boat will not harm the insulation. Sounds like you have an aluminum boat? Remember to support the wire so it doesn’t rub and short on the boat…it will blow a hole in your boat if it shorts to the hull with both + and-.
I like to use a piece of ˝ plastic pipe for the motor wires and a separate plastic pipe for the other stuff. Support the plastic again so it doesn’t fatigue the wiring, lots of vibration on a running boat.
I’d suggest a marine distribution panel. These have separate fuses and switches for each circuit running light/anchor light/bilge manual/sonar/accessories. I also add a cigarette plug, handy for a spotlight, aerator, etc.
The bilge pump should also have and automatic switch that by-passes the panel and goes to an automatic float switch; that circuit has a fuse (inline automotive type). Can be difficult to figure the wiring, but the float switch package has a diagram on it.
DO NOT use house wire nuts EVER. I solder all 12 volt connections then coat with marine grade silicone sealer. If you must use crimp-on connectors or terminals, coat with silicone to hold it together and avoid vibration fatigue.
Not a difficult job if you know a little about wiring, and take your time.
If you put a floor in your boat, you need to install an air inlet scoop on the front, facing forward with a flex pipe to duct the air under the floor. You also need a rear facing duct at the stern. This keeps fuel fumes from building up under the floor, where your wires are.
If the fuel tank is anywhere enclosed (above or below the floor), you need a 12 volt blower with a duct to take the air from the gas area to a vent at the rear of the boat (usually on the side of hull near the gunnel).
Remember a little extra time and money spend on rewiring it right NOW, means you will probably never have a wiring problem. Most folks take short cuts and then their boat is just like their boat trailer……wiring never works when you need it. And with gas, sparks can blow you out of the water.
Safety is always first in boats and boating. Enjoy you new boat.