By Step Guide On Removing Corrosion From A Car Battery Safely
Which Car Battery Terminal To Connect First
Positive first, then negative. 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 isnt always easy to remember the order in which to disconnect and reconnect the terminals. Nevertheless, it is important to connect them in the right order.
Installing The New Battery
Before placing the new battery in position, ensure that both terminals and the cables are rust-free. If they are rusty, you can clean them with water, baking soda, and a wire brush.
Next, lower the battery onto the battery tray with the terminals in the right position, and clamp it into place. Now connect the new battery in the reverse order, connecting the positive terminal first then the negative. Make sure that the battery is secured in place!
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Which Battery Cable To Connect First
Their are a variety of reasons why you might remove your battery from your car, boat, mower, or other equipment with a battery. It could be to charge it or to replace it.
Well, no matter why you removed the battery it brings up a common question when you go to put the battery back in and that is why wire to connect first.
Their is a debate amongst people on if you should connect the positive wire or the negative wire first. Well, after reading this article you will have an answer and reasoning to this question.
How To Tell If Your Battery Needs Replacing

There is a simple test you can carry out to determine the condition of your battery. First, try starting your car at night with the headlights switched on. If the headlights are overly dim, put the vehicle in neutral or park if automatic, and rev the engine. If the battery is failing, the headlights will get brighter as you press the accelerator. A completely flat or dead battery is easy to identify, it simply wont start at all.
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Clean The Battery Tray And Cable Connector
Once battery removal is complete, youll want to clean the battery tray and cable clamp or connector for future use. Do this irrespective of if youre installing a new car battery or just taking the car battery out for a recharge.
Clean the battery tray and connectors of any dirt and corrosion, then spray it with an anti-corrosion compound.
Always make sure each battery cable is secured out of the way.
Dont leave them hanging loose from your engine bay.
Whats next?
If you plan to install a new battery or put back the current one, reverse the entire process:
- Secure the battery with the holding mechanism before reconnecting the terminals
- Apply some anti-corrosion grease on each battery terminal and connector
- When reconnecting the car battery, connect the positive terminal first, then negative
Note: Disconnecting and reconnecting a car battery isnt difficult and is something you can do yourself with a little bit of care and attention. However, whenever in doubt, always get a professional to handle the task.
Now that you know how to disconnect and remove your car battery, lets go over some FAQs.
Disconnect The Negative Terminal Of The Battery
You should always remove the negative battery terminal first, to reduce the risk of sparks which can make the car battery explode.Once the negative terminal has been located, use the wrench to loosen the nut that holds the terminal. Once it is loosened, you can use your hand to remove the nut but make sure you have the safety gloves on.You might face some difficulty in finding the right size socket wrench but once you do, gently turn the screw in a counterclockwise direction until it becomes loose. Make sure to keep the nut in a safe place.
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Turn Off Ignition And Locate The Battery
Turn off the cars ignition switch and remove the key.
Youll then need to locate your car battery.
Most of the time, itll be in the engine bay.
However, some batteries are located in the trunk or under a rear seat making them a little harder to access. Refer to the car manual if you cant find it.
Once youve located the battery, check it for corrosion, damage or leakage.
If a car battery terminal is heavily corroded, disconnecting the cable clamp or connector from the battery post may be more challenging. Dont try to force the connector off, as you could break the battery post.
In this case, youll need to loosen some of the corrosion first. A solution of water and baking soda, and the aid of a wire brush, can help to clear corrosion.
If the car battery is damaged, bloated, or leaking, dont work on it.
to deal with it instead, as youll likely have to replace it.
Which Battery Terminal To Connect First
When you are connecting your car battery, you might get confused regarding the battery connections. But which battery terminal do you connect first? Do you connect positive or negative first?
Always remember that you should connect the positive terminal first.
Any improper battery connection can cause the risk of burning off your cars electrical system and may also lead to battery explosions.
Firstly, you should place the battery in the proper direction and position so that the positive and negative terminals are nearer to their respective cables.
Now attach the positive cable or the red one to the positive terminal and tighten it mildly with a wrench. Similarly, connect the negative cable or usually the black one to the negative terminal. Attach both cables and tighten the nuts. Remember not to overtighten the terminal bolts.
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Why Wont Your Engine Jumpstart
If your efforts to jumpstart the battery dont go anywhere, its likely for one of these reasons:
1. First, it may be that the terminals on your car battery need a deep cleaning. Well offer some tips for this in just a moment! 2. Your battery may simply be very old, and beyond the point at which it can be repairedin which case, of course, it will need to be replaced. 3. Finally, note that there could be another mechanical problem somewhere in the vehicle, such as blown fuses or a bad alternator. A Meineke service technician can help diagnose and fix any of these problems.
Securing The Battery In Place
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Remove & Install The New Battery In The Same Way As You Removed It
Once the battery has been disconnected completely, gently lift it up from the tray and carry it with utmost care. You have now completely disconnected and removed the car battery. Batteries are usually heavy, especially if you drive a truck or an SUV which has a battery weighing almost 40 pounds.To install the new battery you can use the same guide but backward. Put the battery in place and fit the bracket or strap. Start with installing the positive terminal and the negative terminal after. Remember that you often have to re-set the clock and radio settings in your car after you replaced you battery.
Cleaning The Battery Terminals

If you have disconnected your car battery after a long time, you might have noticed that the terminals have corrosion on them. The good news is that you dont need any expensive cleaner to clean the corrosion as you can easily do it with stuff at your home. The things you would require are:
Gloves
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How To Reconnect A Car Battery
This article was co-authored by Hovig Manouchekian. Hovig Manouchekian is an Auto Repair and Design Specialist and the Manager of Funk Brothers Auto, a family-owned business operated since 1925. With over 30 years of experience in the automotive industry, Hovig specializes in the process of auto repair and maintenance. He is also very knowledgeable in common automotive issues and needs including engine repair, battery replacement, and windshield accessory and maintenance. Hovig’s knowledge and hard work have contributed to Funk Brothers Auto winning Angie’s List Super Service Award for five consecutive years.There are 13 references cited in this article, which can be found at the bottom of the page. This article has been viewed 52,861 times.
If you’ve had your battery connected to a maintainer over the winter or had to remove it during other repairs, reinstalling it is a pretty simple process. All you need are some simple hand tools and a few other supplies you probably have around the house. It’s important to not only connect the battery, but to make sure the connections are clean and the battery is secure.
Common Signs A Car Battery Needs Replacing
- Car won’t start
- Car won’t start after being jump started
- Build-up of powdery residue on the battery terminals
- Battery warning light on the dashboard
- Check Engine warning light on the dashboard
If your car fails to start without any warning lights appearing on the dashboard, it’s likely that you have a flat or dead battery. Before immediately buying a replacement battery and getting ready to change it, try and jump start the car.
Once you’ve got the car running, take it for a drive with minimal electrical systems in use to try and recharge the battery and then turn it off. Return to the car in a couple of hours or the next day. If it starts without any issues, the battery was simply drained of power however, if the car doesn’t start again, the battery is unable to retain a charge and needs to be replaced.
A battery needs a clear electrical current to work properly. If the battery terminals have a build-up of a whitish or blue residue around them, their performance will be affected. To remove this residue mix a solution of baking soda and hot water and scrub the corrosion off with an old toothbrush. Getting rid of the residue can sometimes solve the issue of a faulty battery.
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What Does The Car Battery Do
The main battery function in the car is to provide a spark to the starter to crank the engine.
The car battery also provides power for every electrical component in your car from the headlights to the onboard computer.
When your car is running, the alternator recharges the battery.
But when the engine is off, your battery is running on its own stored charge. This is why its essential to avoid unnecessary drain from any electrical system when youre not running the car.
Connecting The Battery Terminals
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Safety Tips Before Disconnecting The Battery
Here are some important safety tips you need to keep in mind before disconnecting the car battery.
- Batteries store electric charge and might give you a small shock if not handled properly. Before disconnecting the battery, make sure you are not wearing any jewelry such as a ring, watch, or a bracelet. If the battery comes in contact with any metal part it can cause an electric shock.
- Always carry out the battery removal procedure in an outdoor space as the batteries contain acids which release harmful gasses. Working in an open environment will minimize your exposure to any hazardous gas.
- Make sure the area where you are working is completely dry and covered. Never work in an environment which is damp or has water nearby.
- By removing the battery terminals, your settings in the clock or radio may get reset and you also may have to enter the radio code. If you do not have the radio code you may have to go to a dealership for them to unlock the code. You can add a small amount of power to the system while replacing the battery but is only recommended if you are a skilled mechanic because working with the electrics connected can be dangerous and you can damage electronics.
Step : Find The Car Battery
Although it might sound silly, not all car batteries are located under the bonnet in the engine bay. Consult the owner’s manual to confirm where the battery is placed – it could be in the boot or under one of the rear seats to save space or enhance weight distribution. It might also have a plastic cover to protect it which needs to be removed.
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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 either battery terminal, use zip ties to hold it in place. Better still, buy yourself a battery-disconnect switch , which will serve the same purpose as removing the cables and will be there whenever you need it.
Shut Everything Off And Find The Battery

- Make sure your vehicle is not running and all electrical components are off before starting the battery disconnection process.
- Open your vehicle’s hood if that’s where the battery is housed, as it is in most vehicles. If your battery is somewhere else, do whatever you need to do to gain access.
- Remove the red plastic cover from the battery’s positive terminal.
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Do I Need To Disconnect Both Battery Terminals
You will need to disconnect both battery terminals in the appropriate order in order to replace your vehicles battery.
With that being said, if you only want to save your battery from draining while youre away on a vacation , youll want to disconnect only the negative terminal of the battery.
Simply disconnecting the negative terminal will safely break the circuit and your cars electronics will not be draining your battery while youre away. If you disconnect the positive as nothing bad will happen, but you wont be accomplishing anything more than by simply disconnecting the negative. Now, youll just have to reconnect both of them instead of one .