How to Disconnect a Car Battery

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How to Disconnect a Car Battery

Do you know how to disconnect a car battery? Which battery cable should be removed first? let's say you need to clean or replace the battery of your car so you disconnect the battery. Here's what you do to disconnect the car battery.

How to disconnect a car battery

1. First is to park the car in a safe place then turn OFF the engine, make sure that the car is a park on level ground and the parking brake is engaged, and use a tire stopper for safety purposes of shift the gear into reverse gear if there is no parking brake or tire stopper.

It is very important to turn off the engine before disconnecting the battery because the battery contains electrical charge and flammable gas produced by corrosive agents, this is done to avoid the possibility of the fire accident.

2. Now, Locate the battery negative terminal. Usually it contains a black plastic indicator label or a negative symbol embedded on the battery casing, however, if you cannot find both locate the word “NEG” on the battery case near the terminal. The terminal with a red plastic label is the positive or with a positive sign embedded on the battery casing located near the terminal, sometimes a word “POS” is printed on the casing near the battery pole.

3. Once the negative terminal is located, check the type of tools to be used for loosening the terminal nut. Usually, an open wrench or socket with a size 10 mm is used to loosen the terminal nut.
Disconnect the negative terminal first, this is to prevent short circuit when the tools you use touches the body of the vehicle.

If you disconnect the positive terminal first, there is a possibility that the tool touches the vehicle body and short-circuited the system.

4. Disconnect the terminal. Start disconnecting the cable on the negative terminal. Remember that it is not necessary to remove the nut on the terminal you just need to loosen the nut of the battery cable to disconnect the terminal.

5. After the negative terminal was disconnected, proceed with the disconnection of the positive terminal.

6. Now loosen the battery clamp to completely remove the car battery.
A disconnecting car battery can become dangerous if not done correctly that is why it is important to know how to disconnect a car battery so that you may avoid an accident when you want to replace your car battery.

To replace the battery, be sure that the battery is mounted correctly, with the side of the terminal facing the right side of the vehicle. Be sure that the battery tray and the pressing board are correctly fixed so as to prevent the battery from moving in the event of an accident or emergency braking.

How to Jump Start a Car Battery

Jump starting a car is easy but should be done correctly so that accident such as a battery explosion can be avoided.

Read more : How to Jump Start a Car Battery

The disconnecting car battery will not only applicable when replacing a battery but also when you are about to work on any electrical parts of your car. When returning the battery do the sequence in reverse position which means that the positive terminal must be connected first before the negative terminal is connected.

Only use a battery of the same model and the same specification as that of the battery to be replaced. Otherwise, there may be some situations where the battery is of inconsistent dimensions or different terminal positions, thus it is likely to cause battery damage, leakage or fire.

Related Articles:
How to Jump Start a Car


  1. should I disconnect the battery when the car is being left idle for three months or more?

    1. Disconnecting the battery will only prolong its discharging than when it is connected to the car and is not a guarantee that it can still be use after three months. Battery will self discharge even when not connected to the car and usually it will only takes about 45 days approximately to self discharge. So, even when the battery is not connected and left it for three months the battery charge will be gone. My advise is to left it connected to the car and have someone start the car for at least every week to let it charge.

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