Do you want to leave your car but you are frightened about the draining of your car battery

Are you thinking of disconnecting the car battery from the car before leaving your car

Here’s a detailed discussion in this article about how you have to deal with the car battery before leaving the car and about its procedure.

Can I leave my car battery disconnected overnight?

Leaving the car battery terminals disconnected overnight causes the battery not to drain and helps to preserve your car battery’s health. You can either disconnect the car battery, or you can use the negative terminal car battery switcher to disconnect the negative terminal.

can i leave my car battery disconnected overnight

Car batteries are the primary energy-providing sources responsible for the car to start if the car battery drains, the car won’t start.

The car battery has two cables that are connected directly to the two terminals termed battery terminals.

The battery terminals are of two types. One is the positive terminal, and the other is the negative terminal. A car battery has plates in it and leads oxide that is involved in the chemical reactions used to produce the potential energy that is used to start the car.

Draining the car battery cause the battery power to minimize to a specific extent that the car cannot start properly. A proper battery provides enough voltage to the car to start the engine, but if the battery drains, it will not be able to provide enough voltage to start and not work properly.

There is various reason that causes the draining of the car battery, so you should have to prevent or deal with that issue so that the battery would not drain. 

There are various factors that can cause your car battery to drain overnight that are as a parasitic draw, trickle charger, negative battery post, some fault in the steering wheel, because of dashboard lights, ambient temperature, and many more reasons.

In the car, we mostly use lead acid batteries, and that batteries do not get cold or flat means these batteries need a moderate temperature.

Safety measures you have to follow:

There are various measures that you have to keep in mind and need to implement on those before going to disconnect the battery terminal, and you have to handle the battery carefully.

How to safely disconnect the car battery:

As you are dealing with a car battery post that can drain, it might be due to some parasitic drain or somehow for another reason, and you have to change or disconnect the car battery or battery juice to avoid unnecessary expenses, you must know the right and wrong ways to do that.

Way of disconnecting and connecting the car batteries:

The car’s battery, when connected to the car for no use, results in healthy battery drains. To avoid this, you have to remove the battery terminals from the car.

There is a proper procedure to disconnect the car’s battery and also for the new battery to connect again.

First of all, when you are going to disconnect the car battery, make sure that the ignition key is locked, and the key is out of the ignition key.

This is for the safety purpose of turning off all the electrical systems or any other systems or other components related to the electrical system against any kind of electrical danger. Then make sure that all of the doors are closed, and all the led and doom lights are off.

Then you need to know which side of the battery terminal is positive and which one is the negative terminal. This is mentioned over the battery.

You can also make sure by using the fact that the positive cable tie is of black cover and the negative cable tie is of red cover.

Once you are sure which side of the vehicle battery terminal is positive and which one is negative, then start with the negative cable tie.

The negative sign represents the sign of electrons, and disconnecting the negative cable tie prevents the flow of electrons. The electrons travel from the negative terminal to the positive terminal which can be termed as the current flows from high to low potential and then removes the positive cable.

Similarly, when you want to reinstall the new battery, first attach the positive cable and then the negative cable. This is the right way of disconnecting the negative terminal of the battery and reconnecting the battery just to avoid any kind of electrical current.

Items required for disconnecting car battery:

As you are done with the basic knowledge about the procedure regarding the red terminal and black one. You have some items that are required during the same procedure.

Safety gloves:

Safety gloves are one of the most expensive affairs that are to keep in mind while dealing with metal parts. If you do, by chance, disconnect the positive cable rather than the negative battery terminal, you may experience a high-voltage current. For this safety, you are advised to wear safety gloves.

When the current touches, it passes from your body, causing the person to hurt, which is painful. If you properly connect the battery or want to safely disconnect the battery from the engine bay, you have to buy good quality safety gloves that will prove beneficial for you and your vehicle.

Socket wrench:

A socket wrench is one of the most equipment that is required to replace or disconnect the battery from the car. To save the life cycle of the car or preserve the battery juice for a short time, according to the car owner’s manual. You must need a correct size wrench for the visual inspection of the vehicle.

Removal of the negative terminal after the positive battery cable:

The battery was carefully disconnected from the vehicle. As discussed, there is a procedure to remove the battery from the vehicle when the vehicle is free for a long period of time to avoid minus sign-in battery functioning and to avoid the use of jumper wire.

Always the negative terminal is removed first. If you remove the positive terminal of the batteries first, it will cause electrical damage.

The negative terminal of the vehicle battery cable with a black cover is attached to the metal parts of the engine bay, but the positive cable with the red cover is attached to each of the systems of the engine.

When the positive terminal is removed first, the current is still reaching the metals in the car, and that current can jump within different parts that can cause the short circuit. So in order to prevent all of these hazards, disconnecting the negative terminal proves beneficial.

Will Disconnecting a Car Battery Harm Computer:

When you disconnect the battery terminal from the battery, the battery functions are stopped. The battery tested that it is used to start the internal combustion engine bay and many more functions of the car, including the electrical system.

The electrical system of the car is commanded by the computer of the car. The main function of the computer is to command the system what is put in the settings.

If you disconnect the battery tray for a long period, the computer forgets all the commands and functions to perform as they are removed from thier short-term memory. So the longer period of removal or disconnecting the car battery tray can harm your computer, and when you drive the car after a long the ECU forgets what to do, and you feel discomfort with the drive for a while.

So if you are doing to disconnect the car battery post for a longer period, you should have to do some safety features for your car computer, or you can start it after some time to save it from any kind of short circuit or electrical danger and to save money.

Will disconnecting the battery resets your engine check lights:

If you turn off the key in the ignition switch and then turn it on or not, some of the power is still in the computer electrical system that is used by the engine bay to turn on the check engine lights.

This power can cause complications regarding the automatic transmission of the engine to check. To overcome we need to disconnect the vehicle battery for some time.

This procedure removes all the power from the computer, and the engine check lights restart when reconnecting the battery to the car. This helps the car to behave ethically if you have to check whether the car is working properly or not.

How long can you leave the car battery disconnected?

Disconnecting the car battery terminals might be helpful, but not for a too long period. If you are going to leave your car for a few weeks, it is helpful that you disconnect the negative terminal and positive terminal of the car battery from the car and save it in a safe place; thus, you can store your car battery for about more than six months.

Will a car battery recharge itself overnight?

No, a car battery cannot charge itself overnight. A car battery is used to start a car that has the potential stored in it in the form of chemical energy as a result of chemical reactions taking place in the battery.

Battery recharge occurs when a battery charge is connected directly to the battery or, as a result of the alternator’s running, the current is regained during the car driving. But a car cannot charge itself overnight.

Can a battery drain with the negative cable disconnected?

You can leave a car with the negative terminal of the battery cables disconnected, but it can drain your battery. If you want to keep your battery safe without getting drained, you should disconnect the battery from the vehicle.

The connection of the battery to the car, even if it is not used, drains the car battery percentage of twenty percent of the total battery health, and if the negative terminal is disconnected, it causes the battery to drain about five to ten percent from the healthy battery.

Which terminal is removed first while disconnecting the car battery?

If you are going to disconnect the car battery from the car, there is a proper method to do that. You first have to remove the negative terminal of the battery cables and then the positive terminal.

It is only for safety purposes. If you used to remove the positive terminal first, it could cause the battery to cause electrical systems to create a short circuit.

What causes a car battery to drain?

There are certain reasons that cause the car battery terminals to drain. One of the main reasons why the car is not in use is that the battery is connected to the car when the car is in use; the led lights, faulty alternator, the weather, and many more factors can cause the battery to drain.

How can you preserve the battery without disconnecting the car battery?

If you want to preserve the car battery and not want to drain your car battery, but you are not able to remove the battery from the car, there is a way that you can do it.

If the car battery’s negative terminal is removed, it can preserve your battery as, in this case, the battery drains at less speed than when both battery terminals are connected.


From the article, you came to know how the car battery drains when the car is not at work and how beneficial to disconnect the battery from the vehicle. There are various factors that affect the car battery, and a definite procedure to remove or disconnect and reconnect the car batteries.

Similarly, some of the equipment is required to change the battery. So you must have to follow all these while you are going to take some free time in your car in addition to the anti-theft system.

Related articles:

Similar Posts

Leave a Reply

Your email address will not be published. Required fields are marked *