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How to Attach a Car Battery-Mounted Power Cut-off Switch

car battery switch

Many people who store their vehicle for a length of time like to disconnect the battery from the electrical system of the vehicle. This prevents the vehicle from unintentionally draining the battery. With the battery disconnected, the risks of sparking and fire are also lessened dramatically.

Disconnecting the battery is generally accepted to be a safe storage practice because you never know what kind of furry critters or outside forces could cause an unexpected electrical problem during long-term storage.

Rather than using tools to disconnect your battery cables each time, a battery disconnect device (also known as a power cut-off switch) can be easily installed at the battery, and the power can be disconnected in a matter of seconds using a knob.

Part 1 of 1: Safely install a battery disconnect switch onto your vehicle

Materials Needed

Step 1: Locate the battery in your vehicle. Most car and truck batteries are located under the hood of the vehicle, but in some models, they may be located under the rear seat, or in the trunk.

wrench on cable end

Step 2: Remove the negative battery cable. Disconnect the negative battery cable using a wrench.

  • Tip: On older American vehicles, you would need a 7/16 or 1/2 inch wrench to do this. On newer or foreign vehicles, a 10-13mm wrench is most commonly used to disconnect the battery cable.

cut of switch attached to battery

Step 3: Install the battery cutoff switch. Install the battery cut-off switch onto the negative battery terminal, and tighten it on with the appropriate size wrench.

Ensure that the switch is set to the open position.

negative battery cable connected

Step 4: Connect the negative terminal to the cutoff switch. Now connect the factory negative battery terminal to the battery disconnect switch, and tighten it using the same wrench.

Step 5: Activate the switch. This is typically done by turning a knob that is part of the battery cutoff switch.

hand turning switch

Step 6: Test the battery switch. Test the battery switch in the “On” and “Off” positions to make sure that it is working as expected.

Once functionality is confirmed, visually inspect the battery and connections to confirm that nothing else is coming in contact with the battery terminals or newly added battery cut-off switch.

Whether you are storing your vehicle for a period of time, or you have a vehicle that drains your battery for unknown reasons, a battery terminal disconnect is an easy solution.

If disconnecting your battery on a regular basis due to a drain isn’t the solution of your choice, consider getting a certified mechanic from YourMechanic to inspect the battery if it is dead and replace it.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
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