How to Wire an Auxiliary Battery

What You'll Need
Battery isolator
Crimp connector

In order to get the most use out of your auxiliary battery, it is important that you wire it properly. If you don’t, you will lose volts that could go into powering your utilities.

Step 1: Cables

Before you begin making any connections, you need to be sure you have the correct cables. The more voltage you use, the larger cables you will need. In this case, energy can be compared to running water, the more room available, the more energy will be able to flow. You do not want to power your appliances with only a trickle of the energy available to you. Don’t buy cables that are overly long. As nothing is 100 percent efficient, energy will be lost as it runs through the cables. The less distance there is between point a and point b, the less energy will escape.

Step 2: Connections

For safety and efficiency, you need to have flat, clean and smooth connections. Use crimp connectors to connect the cable ends to the battery. The type of connector you use should be determined by the type of cable you have. Be sure to tighten the connection frequently. A secure connection ensures a steady power supply. Run one cable from the positive connection to the positive connection on the main battery. The second cable, the negative or ground cable, should be connected to the negative terminal on the main battery. The cables should not run through an area where there is the possibility the wire may be damaged.

Step 3: Battery Isolator

A battery isolator should be used when there is any possibility of charging the auxiliary battery. The isolator will prevent the main battery from fully depleting its charge. If you need to start your vehicle, and the main battery is depleted, the isolator will use the auxiliary battery to start the car. It separates the batteries once the auxiliary is charged. It also monitors the voltage of both batteries. The isolator should be installed according to the manufactures instructions.

Step 4: Storage

You need to keep your battery in a cool, dry area. Do not store it in a place where there is any possibility of an explosion, fire or excessive dust. Most batteries are not completely sealed. Dust and moisture will only harm the battery and cause corrosion. Once the battery begins to corrode, it will be hard to make stable connections between the batteries.

How you wire your auxiliary battery will be determined by what appliances you choose to hook up. These are some basic guidelines on how to best utilize your battery. Whenever you have a new device you wish to attach to the auxiliary battery, follow any extra instructions given in the owner’s manual. That will give you a more precise idea how to deal with the space and appliances you have available.