Learning how to disconnect a car battery is an important skill that could save you a lot of money when doing it yourself rather than hiring a professional mechanic. To disconnect the battery, you need to follow these steps:
Auto Repairs Are EXPENSIVE
- Prepare necessary equipment
- Locate the battery
- Differentiate between the negative and positive terminals
- disconnect the cables
- Take the battery out while holding the clamp
Cars batteries are not designed to last forever, and there will be a bit of time to either replace or repair them. In some situations, repairing the car battery requires disconnecting the battery and taking it out. Thus, learning how to disconnect the car battery is an essential skill that could save you a lot of money.
The good news is that you can disconnect the car battery yourself, which means you don't have to worry about hourly rates for hiring a professional mechanic. However, since the car battery has some electrical voltage, it is important to follow a certain procedure to disconnect the battery without causing any issue to yourself or the vehicle.
This article provides you with a step-by-step procedure on how to disconnect the car battery. The procedure is simple enough, and even if you don't have any previous experience with disconnecting car batteries, you should follow along and not have any trouble.
Why do I need to disconnect the car battery?
Before we discuss the details on how to disconnect the car battery, we would like to give you an overview of situations where you need to disconnect the battery here at once you know these situations, you understand how important it is to learn this skill before an emergency happens where you don't have any close by help or support.
Here are some of the common situations where you need to disconnect the car battery:
For maintenance purposes
your car's battery is one of those components that cannot be repaired while sitting in its tray. Therefore, before performing any maintenance, you have to take the battery out. Learning how to disconnect the car battery and take it out yourself can save a lot on repairing the battery.
Note that fixing a car battery is not a cheap process, and the more you can do towards it, the more you can save.
For charging purposes
in some vehicles, you might need to recharge the battery using a certain external charge source. Therefore, you won't be able to do so unless you take it out.
For replacement purposes
obviously, if your car battery is at the end of its lifetime, the only solution for you to get your vehicle going is by replacing the car battery. To replace the car battery, you must disconnect the old one and take it out before installing the new one.
Keep in mind that car batteries need replacement once every two to five years, which is not a very long-time frame during the lifetime of your car. Therefore, learning such skills through a short article can help you save money that you'll have to pay once every two to five years.
For storage purposes
some automotive experts recommend disconnecting the car battery when you're planning to store it for extended time frames here; of course, there might be some debate about whether to disconnect the battery or not, but if you decided to go this route, learning how to do so by yourself without needing a mechanic can save you some money as well.
How to disconnect the car battery?
No, you understand exactly when it's important to disconnect the car battery; here's all you need to do to disconnect the battery safely without causing any problem:
Prepare tools and equipment
before you start the job of disconnecting the car battery, you must collect all your tools to save yourself a lot of time and effort. Imagine you start the job and figure out that you have to purchase a certain range? That will take you a lot of time and will make the process much longer.
In general, you will need the following items:
- The vehicles owner’s manual
- a 10-millimeter open-end wrench
- a socket wrench
- an adjustable open-end wrench
- Eye protection
keep in mind that you might not necessarily use all of these wrenches depending on your vehicle's type, but it's good to have them as a backup.
Choose the right location
although disconnecting a car battery does not involve any mess and will not cause any leaks around you, it is important to choose the right location for disconnecting the battery.
An ideal place would be your vehicle's garage or the backyard, where there are not many people or traffic close by.
determine the battery location
depending on your vehicle's make, model, and year, the battery might be located in different corners. Therefore, you must refer to your vehicle's owner’s manual to locate the battery. Usually, the battery should exist under the hood and be secured with a couple of bolts. Of course, this might not be the case in your vehicle, and your manual should give you a better idea.
Referring to the manual shows you where the battery exists and provides it with some guidance on how to detach it based on your vehicle’s specifications.
Familiarize yourself with the battery terminals
you might already know that the battery has one positive and one negative terminal. Disconnecting the car battery requires a certain order, and you cannot simply remove one terminal before the other. Therefore, understanding where and how to distinguish between the positive and negative terminals is a must.
Obviously, the vehicles owner’s manual might have some details, but in general, the positive terminal is either marked with a “+” or comes in red color in old vehicles. On the other hand, the negative terminal is marked with a “-“sign or comes in black color.
Disconnect the battery cables
Among all steps in disconnecting a car battery, is connecting the cables is the most sensitive step that needs to be done with caution. Before you do so, you must put on any protective glasses and make sure that the ignition switch is turned off.
When disconnecting the cables, it is essential to remove the negative cable before the positive one. To do so, you'll need to use a certain wrench, and you might have to wiggle the cable a little bit to get it out freely.
Note that you must not let your wrench touch both the positive and negative terminals at the same time because this could cause some sparks that might put your life at risk. Even if you will know for sure that your car's battery doesn't have any charge or it's not in bad condition, it does not necessarily guarantee that you don't have any residual charge.
When taking out the negative terminal, it is very important to place it away from the positive one while you're working on it. It is not rare that as you are wiggling the positive terminal, the negative cable touches the positive one and causes some damage is.
The worst part about messing up between negative and positive terminals is that it might cause some damage to the electrical components in your vehicle.
Once you are familiar with the right way of disconnecting the cables, disconnecting a car battery should be a piece of cake, and you won't have any trouble in the other steps.
Take the battery out
once the positive and negative terminals and cables are disconnected, the final step is to take the battery out. Remember that depending on your vehicle's type, the battery might sit on a certain clam connecting it to the tray, so it doesn't get out by itself.
Therefore, an additional step of removing the clamp is needed. To do so, you can use a socket wrench, and you will most likely need some extension because the bolts that are holding the clam are usually located at the bottom, where you can't easily reach them.
After disconnecting the clam, you can go ahead and remove the battery from the tray.
That's it! You did it!
Which battery terminal do you take off first?
Whether you’re disconnecting the battery or trying to perform a jumpstart, it is very important to understand the order of which terminal to disconnect first.
In general, you must disconnect the negative terminal before the positive one. When you're putting the battery back, you must connect the positive terminal first and then the negative one.
Long story short, you don't want to leave your negative terminal connected to the battery by itself without a positive one.
Why is it recommended to disconnect the battery for storage purposes?
As we indicated before, some automotive experts recommend disconnecting the car battery if you're planning to store it for extended timeframes. When disconnecting the car battery, you'll get the following benefits:
You'll save a lot on the battery charge
When you disconnect the car battery, you are preventing it from draining. However, many internal components might still deplete the car battery even if the engine is not running. For example, the car's clock and the onboard computer system still uses the battery charge when the engine is not running.
You'll save a lot on buying a new battery
if you disconnected the car battery, it would not rain, and therefore, its lifetime can get extended. Thus, you don't have to worry about purchasing a brand-new battery even though it is not very expensive, but it's still a good amount of money to save.
Are there any alternatives for disconnecting the car battery?
If you did not have the time to disconnect the car battery and still would like to save its charge, you could use a trickle charger. The trickle charger can slowly recharge the battery as it drains out. Therefore, it will act like the battery is not connected to any electrical components, and no charge is taken away from the battery.
How long can a battery last if disconnected?
According to experts, if you disconnected the car battery, it could last up to six months. But, of course, it can last even longer if you charge the disconnected battery from time to time.
Conclusion
Understanding how to disconnect a car battery is a very important skill for any driver. It can save you a lot of money do it yourself down hiring a professional mechanic.
To disconnect the car battery, you'll need to prepare the necessary equipment, locate the battery, differentiate between the positive and negative terminals, remove the cables, and then take the battery out.
If you notice that you will need to remove the battery frequently, it might signify that your battery is not in great condition. If that's the case, replacing the battery might be a must to keep your vehicle going and save you many headaches. Keep in mind that battery prices are not very cheap, and if the car's battery is not the only problem in your vehicle, it might be the right time now to sell your car to Cash Cars Buyer instead and use the money towards a better vehicle.
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FAQs
What is the correct order to disconnect a car battery? ›
When disconnecting the cables from the old battery, disconnect the negative first, then the positive. Connect the new battery in the reverse order, positive then negative.” When you are replacing your car battery, It isn't always easy to remember the order in which to disconnect and reconnect the terminals.
Which terminal to disconnect first? ›Disconnecting the Old Battery
“Disconnect the negative terminal first and then disconnect the positive terminal,” Hines tells us. The reason it should be done in that order, he says, is to mitigate the risk of electrocuting yourself.
If you disconnect the positive terminal first, one slip of your wrench could send a direct short to the ground, which can be very dangerous. Its possible that you could experience a huge spark, the wrench could melt in your hand or the battery could even explode!
Which battery terminal must be disconnected first and why? ›Removal of Old Battery
Remove the negative (-) terminal first. This precaution is necessary to avoid damage to wiring and the battery by accidentally grounding tools. Remove the positive (+) terminal.
Never connect the black cable to the negative (–) terminal on your dead battery. This is very dangerous, could result in a possible explosion. Make sure you follow the instructions in your owner's manual when jumpstarting your vehicle.
Do you connect black or red first? ›Do You Hook Up Red or Black Jumper Cables First? Once the two vehicles are in place, turn off both and open the hoods. Attach the red jumper cables first. Start by clamping one red cable to the positive side of the battery that won't start.
Will disconnecting my car battery reset the computer? ›Disconnecting your battery and draining the power to cause an ECU reset is one of the most common fixes for a check engine light that won't go away on its own. Doing so is equivalent to a hard reboot on a desktop computer, which is a standard way to eliminate many common problems.
Do you have to disconnect both negative and positive? ›The positive and negative battery cable ends each have a nut or bolt connecting them to their respective battery post. Your job is to disconnect both. However, DO NOT disconnect the positive terminal before the negative one. Doing so can cause an electrical short.
Why do you disconnect the negative terminal first on a car battery? ›Negative first
It's important to disconnect the negative side of the battery first, otherwise you can cause an electrical short if the positive is removed first.
It is not a problem.
The reason they say to remove the negative first is because it is safer for you. The negative cable in all modern cars is attached to the chassis of the car. SO when you put your wrench on the negative post to loosen it, and the wrench hits the chassis, nothing happens.
What cable goes first when jumping a car? ›
First the clamp of the red cable is connected to the positive terminal of the assisting vehicle. The other end of the red cable is connected to the positive terminal of the broken down vehicle. Then the black clamp is connected to the negative terminal of the assisting battery.
When installing a battery disconnect switch positive or negative? ›Install the disconnect switch on the negative battery cable: Installing the switch on the negative side of the battery reduces the potential for sparking, just as connecting the negative battery cables AFTER connecting the positive cables reduces problems with electrical fireworks.
Why do you connect positive first? ›Connect positive first, negative having less potential won't arc. The higher the voltage, the greater the chance of arcing and fusion. On a car if negative first and you are touching any metal part of car, when attaching positive there is possibility of arcing through you. Your body becomes part of the circuit.
Which wire do I disconnect first on a car battery? ›Disconnect the Battery Cables
The terminals will be marked positive and negative. Make sure you disconnect the negative terminal first. Lay the disconnected negative cable carefully to one side, making sure it's well away from the battery terminal.
The red one is positive (+), the black one is negative (-). Never connect the red cable to the negative battery terminal or a vehicle with a dead battery.
Why do you connect red first? ›You connect the positive terminal first. It is easy for your wrench or tool to make contact with something grounded on the car. If you connect the positive terminal first, the ground isn't connected. So your first connection is safe.
How do I reset my ECU after I disconnect the battery? ›All you need to do to reset your ECU is interrupt the power flow from the car battery to the car's ECU. The most efficient way to disrupt the ECU's power supply is to disconnect the negative cable from the negative terminal.
How long does it take for the car computer to reset? ›Here's something you probably don't know: after clearing the car's computer you will need to drive for about 50 to 100 miles. As you drive your car the computer will monitor all the sensors and register the results.
Will the car battery drain if I disconnect only the negative terminal? ›Will the Car Battery Drain if the Negative Cable Is Disconnected? A car battery will self-discharge at a rate of 5-15% per month with the negative terminal disconnected. However, the alternative option of leaving the battery connected while it isn't being used will drain at close to 20% per week.
Does disconnecting battery cause problems? ›Disconnecting or replacing a battery on a computer-equipped vehicle may cause starting, driveability and a number of other problems, including loss of air conditioning, power accessory functions (door windows, seats, sunroof), false warning lights, even damage to certain electronic modules!
What happens if you disconnect the positive terminal while car is running? ›
Removing the battery from the circuit allows those spikes and transients to travel around, endangering every semiconductor circuit in your car. The ECU, the speed sensitive steering, the memory seat adjustments, the cruise control, and even the car's stereo.
Which terminal to disconnect to save battery? ›Disconnect The Negative Battery Terminal First
When disconnecting a car battery, always remove the negative connector (negative clamp) from the negative terminal first.
When stored properly out of the car in a secure place, a detached car battery has the chance to last up to six months. Just like any other car battery, it will need charging, but not as often as if it were attached.
Will my battery drain if I disconnect negative terminal? ›Will the Car Battery Drain if the Negative Cable Is Disconnected? A car battery will self-discharge at a rate of 5-15% per month with the negative terminal disconnected. However, the alternative option of leaving the battery connected while it isn't being used will drain at close to 20% per week.
Why is positive terminal connected first? ›The positive terminal is usually marked with a plus sign. Remember the simple rule that connecting and disconnecting a battery is in reverse order. Positive first when connecting a battery, negative first when disconnecting a battery cable. That way, you won't damage your battery or get shocked.
Do I only need to disconnect negative terminal? ›You can disconnect whichever terminal you want, or even both, it won't discharge. Whichever one you choose results in an open circuit so no current can possibly flow.
Should I remove the positive or negative terminal to shut down car? ›Use your socket wrench or adjustable wrench to loosen the nut holding the cable onto the negative battery terminal. The terminals will be marked positive and negative. Make sure you disconnect the negative terminal first.
Which battery cable do you take off to test the alternator? ›You can check the alternator by simply starting your car and then disconnecting the negative battery cable. Be careful doing this, though, because there are a lot of moving parts in your engine compartment that could cause injury.
How long will disconnect car battery hold charge? ›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.
What happens if you disconnect the battery while the car is still running? ›Removing the battery from the circuit allows those spikes and transients to travel around, endangering every semiconductor circuit in your car. The ECU, the speed sensitive steering, the memory seat adjustments, the cruise control, and even the car's stereo.
Will a car battery drain if I disconnect only the positive terminal during the night? ›
Will a car battery drain if I disconnect only the positive terminal during the night? No, it won't drain overnight if you disconnect the positive lead. However, it's very bad practice & can be dangerous, assuming the car is negative earth/ground. NB: Just about every car built since about 1965 is negative Earth.
Which cable goes first when jumping a car? ›First the clamp of the red cable is connected to the positive terminal of the assisting vehicle. The other end of the red cable is connected to the positive terminal of the broken down vehicle. Then the black clamp is connected to the negative terminal of the assisting battery.
How can you identify the positive terminal? ›Cut a potato into two halves and insert the copper wires of a tester connected to 2 ends of the battery. After some time, a greenish blue spot develops around the wire connected to the positive terminal of the battery, . In this way we can identify the positive terminal of the battery.
Is the positive terminal always on the left? ›Some batteries sizes are available with terminals in many different configurations, but two main configurations are: positive on left and negative on the right corner. negative on the left and positive on the right corner.
Which terminal do I disconnect to save battery? ›Disconnect The Negative Battery Terminal First
When disconnecting a car battery, always remove the negative connector (negative clamp) from the negative terminal first.