How To Disconnect A Car Battery?

Your car won’t start. You have a dead battery. We know, it’s a pain! You’d like to pull it out and get it checked at an auto parts store or maybe even replace it—and you want to do it yourself to save a few bucks.

If you haven’t attempted to disconnect a battery before, we’re here to help. It’s simple and requires just a couple of tools. But you need to know how to do it properly to ensure your safety and make sure that nothing bad happens to your vehicle or its electrical system. Follow these steps and the operation will go smoothly and quickly.

When Do You Need To Disconnect A Car Battery?

Car batteries are one of the most crucial components of your vehicle, but you may need to disconnect them for a variety of reasons:

  • To perform maintenance on your vehicle: Some types of maintenance require you to disconnect the battery to prevent the risk of electrical issues or danger to yourself and your vehicle.
  • To replace or recharge the battery: Batteries need to be replaced from time to time (every 2-5 years in most cases), so disconnecting the battery would be mandatory for replacement. Additionally, if your battery is dead and can’t be charged while seated in its holding tray, you would need to remove the battery and then charge it.

How To Disconnect A Car Battery?

Ready to disconnect your battery? Here’s what you need to do:

#1. Turn Off the Engine.

Begin by turning off your engine and removing the keys from the ignition. Attempting to disconnect the battery with the engine running could cause bodily injury and vehicle damage!

#2. Locate the Battery and Terminals.

In most vehicles, the battery is in the engine compartment. However, some cars have batteries in the trunk or under the rear seat. Consult your vehicle’s manual to determine the battery’s exact location.

After you locate the battery, look for the battery terminals. The negative terminal should display a negative symbol (-) and usually has a black-colored cable, while the positive terminal should have a positive symbol (+) and usually has a red-colored cable.

Related Posts: How to Tell Positive and Negative Terminals on a Car Battery?

#3. Disconnect the Negative Terminal.

how to disconnect car battery

It’s important to disconnect the negative terminal first to prevent any electrical shorts. Use your wrench to loosen the nut or bolt securing the terminal. After it’s loose, carefully lift the cable off the battery post and set it aside.

#4. Disconnect the Positive Terminal.

Repeat the same process as Step 3 but for the positive terminal. Ensure that the positive and negative terminals don’t touch each other or any metal surface. NOTE: Isolate the positive cable end by wrapping it in a non-conductive material such as a towel.

#5. Loosen and Remove the Battery Hold-Down.

The battery hold-down holds the battery in place while driving the vehicle. Locate the fasteners and loosen or remove them as necessary with your wrench, then remove the battery hold-down.

#6. Remove the Battery.

Carefully remove the battery and ensure it remains level as you pull it out from the vehicle to prevent battery acid from spilling. Also, be mindful of its weight. Car batteries can weigh 40 pounds or more, so lift with your legs to help avoid back injury. After you remove the battery, set it on a dry, flat surface.

Related Post: How to Charge a Car Battery?

How to Reconnect a Car Battery?

Your negative and positive cables are a good distance from the battery terminal. Your battery is lying on a flat surface. And most importantly, you’re safe because you were careful when removing your car’s battery.

If you can check all those boxes, then you’re ready to learn how to connect a car battery correctly!

1. Clean Cable Contacts And Battery Terminals.

Your replacement battery (or existing one if it’s still good) should not be installed until the cable contacts and terminals are corrosion- and debris-free. Follow the steps in this blog article to do it properly: How to Clean Battery Terminals with Stuff You Already Have

#2. Install The New Battery.

Now for the fun part: learning how to connect a car battery properly.

  • Lift your new battery (remember to keep it level) and set it in the battery tray or compartment.
  • Reinstall the battery hold-down
  • Reconnect and tighten the positive cable to the positive terminal.
  • Reconnect and tighten the negative cable to the negative terminal.

Installing a new or existing battery may reset your car’s clock. Set yours back to the correct time, and then you’re done!

#3. Test the Battery.

Now, it’s the moment of truth! Start the car and check if everything is functioning properly. Test the headlights, horn, and other electrical components to ensure they work as expected. If there are any issues, double-check the battery connections and make sure they’re secure.

If You’re Storing Your Vehicle

A Final Note: If you’re removing the battery cables to store your ride for an extended time, know that a fully charged battery will hold its charge for six months to a year if you disconnect the negative cable.

If you’re disconnecting the negative cable and leaving the battery in place, be sure to push the cable out of the way. If there’s any chance that it might spring back into place and touch battery terminal, use zip ties to hold it in place.

Better still, buy yourself a battery-disconnect switch (it attaches to the negative terminal), which will serve the same purpose as removing the cables and will be there whenever you need it.