Wiring a Boat Battery Switch

Lead Image
  • 1-4 hours
  • Intermediate
  • 10-50
What You'll Need
Marine battery
Battery box
Battery terminals
Battery switch
Philips screwdriver
Drill and bits

A boat battery switch is a safety requirement on most boats that are capable of holding several passengers and contain more than one battery. They are very useful for shutting off the power quickly when you need to in the case of an accident or injury. Some boats carry more than one battery so they can switch over to another when the first one depletes its energy. Being able to switch to another fresh battery is a great way to keep the electronics of the boat functioning. If you need to wire your own boat battery switch, here are some step-by-step instructions to do it correctly.

Step 1 - Choose Location for Switch

When you begin to plan out where you want to place your boat battery switch you will need to take some things into consideration. You want the switch to be within close proximity to where you will be driving the boat so you can get to it quickly. However, you do want to keep it away from the general traffic area. Below the driver's cockpit is a good place, as well as inside one of the seat compartments.

Step 2 - Measure for Wire Length

Use a measuring tape and measure the length you will need for the battery wire. It is important to keep in mind you should not measure in a straight line from the battery to the switch location. The wire is going to be hidden alongside the edges of the boat, or under the carpeting. Follow the actual routing that the battery wire will be following as it goes from the battery to the box. One very good tool to use for this application is a fabric tape measure that is often used by tailors. Once you have the length for the battery to the switch, you will need a second wire for going to the ground spot. Measure this length of wire in the same manner as the main positive wire.

Step 3 - Connect Wire to Solenoid

Measuring for the positive battery cable that runs from the battery to the box and the negative ground wire, is not the only measuring you need to do. You will also need to find the measurement from the battery switch to the solenoid where the battery's positive cable is going to be connected.

Step 4 - Connect Wires

Attach a battery terminal to the end of the positive cable and run the wire along the route you chose to where the boat battery switch is going to be. Attach one end to the battery switch with the use of your tools. Connect another wire to the solenoid by connecting the wire to the OUT terminal on the battery switch back to the solenoid.

Step 5 - Connect Ground Wire

After the wires have been connected to the battery and the solenoid, you will then need to connect the negative battery cable to something metal. Look for a place on the actual chassis or close to the main battery as you can. Connect this wire to the ground source and to the negative battery terminal.

Step 6 - Turn on Battery Switch

Once all the connections are made you can now attach the positive battery cable to the battery and turn on the switch.