Nowadays car owners add a variety of electronic devices to their vehicles. Sometimes they are simply too much to handle for the car battery. In order to make this last longer, it might be a wise idea to install a second battery. This can provide power for one or more devices and protect the first battery from draining too fast. A second battery can be installed anywhere in the car, but it has to be in a place that allows it to connect to the alternator. In the absence of this connection, the battery drains in no time.
Here are the steps for installing a second battery in your car:
Think about the place where you want to install the second battery. You might consider the engine compartment, but in most of the cases, there is no room for a second battery there. Instead of making changes, you might better install the battery in the trunk especially if you want to power the subwoofer with it.
Start by installing a battery tray of the adequate size. You have to screw it in the trunk’s floor and you have to drill a hole close to it in order for the cables to fit. Pay attention to the gas tank because you do not want to make holes in it.
Disconnect the car battery by first taking out the negative cable and then the positive one that connects the battery to the alternator. You can unbolt the cable or simply cut it off close to the alternator.
Continue by installing a battery isolator. Connect the cable you have just disconnected from the alternator to the isolator by removing part of its insulation and re-connecting it to the side terminal of the isolator.
Make a connection between the alternator and the central terminal of the isolator usually marked with an A. Use two extra wires: one should go from the alternator to the central terminal and one should travel from the third terminal of the isolator to the second battery.
The longer wire should connect to the positive terminal of the second battery. Then this terminal should connect to the device you want to power. You can either screw or crimp the wire in order to ensure this connection.
Bolt the wires or secure them using clamps to the chassis. Make sure the wires and the clamps you are using do not interfere with any other components. The clear path that you should find for the wires differs depending on your type of car.
Power the car by reconnecting the first battery. Remember to start with the positive terminal. Then ground the second battery by connecting a wire from the negative terminal to a metal component like the chassis.