Replacing a car battery is a common maintenance task for DIYers, but using the proper tools and taking safety precautions is important. The most important tool you’ll need is an open-end wrench, typically 10mm or 13mm, to loosen the terminal clamps. Be sure to check your car’s manual for the specific size.
Wearing gloves and safety goggles is also recommended when handling a car battery, as the battery acid can cause burns, and the battery may produce gases. On rare occasions, there can be an explosion if the battery leaks and there is a spark.
Start by disconnecting the negative terminal first, using your wrench to loosen the bolt head. Be careful not to touch the wrench with any other metal while doing this, as it could cause sparks or electrical shorts.
Remove the old battery and put the new one in place, connecting the positive terminal first. Tighten down the clamps securely with your wrench. A voltmeter and specialty tools like battery terminal cleaners can also be useful. In our guide, you can learn more about how to change a car battery when the battery needs replacing. By the end, you’ll better understand changing the battery, the tools you’ll need, especially the right size wrench for a car battery. (Read What Size Wrench For O2 Sensor)
Understanding A Car Battery
If you are planning to change a car battery or need to replace a car battery, understanding how it works is essential. Over time, the battery may lose its charge and needs replacing. It is important to note that a car battery can be dangerous if improperly handled.
Before you replace the battery, you need to disconnect the battery from your car. This involves removing the car battery cables from the battery terminals. It is important to check your car’s manual to determine the correct battery size and type for your car. Different vehicles require different batteries, and using the wrong type of battery can cause damage to the car’s electrical system. You can replace the battery once you determine the correct size and type.
Correct Wrench Size When You Need To Replace A Car Battery
When working on car battery’s, it’s important to have the right wrench size for a car battery terminal.
Here are some tips to help you identify the correct wrench size for your car battery:
- Your car’s manual will often have information on the size of the battery terminal nuts.
- If you can’t access your car’s manual, use a digital caliper to measure the diameter. Most cars use 10mm nuts (0.4 inches), but some cars may use 13mm (0.5 inches) nuts.
- The nuts may also have markings or labels indicating their size. Look for numbers like 10 or 13, showing the wrench size needed.
- Open-end wrenches, box-end wrenches, adjustable wrenches, and crescent wrench make a suitable battery wrench. Choose the type of wrench that works best for you and your car.
Required Tools
Regarding changing a car battery, you’ll need some basic tools. Here’s a rundown of what tools you need:
Wrench
The most important tools needed are a wrench. The size of the wrench you’ll need depends on the battery terminals. Most batteries will have hexagonal or wing-nut style terminals, so you’ll need a corresponding socket wrench or an open-end wrench. A 10mm (0.4 in) wrench is the most common size for battery terminals. (Learn How Much Does It Cost To Dyno Tune A Car)
Pliers
You’ll also need a pair of pliers to hold the bolt head in place while you loosen or tighten the nut. Vise pliers or adjustable pliers will work fine.
Hammer
A hammer can also come in handy. Sometimes the battery terminals can be corroded or stuck, and a few gentle taps with a hammer can help loosen them up.
Other Tools
Besides the above tools, you may also need:
- A socket wrench set
- A battery terminal cleaner
- Safety glasses
- Gloves
- A battery tester
Keeping a tool box in your car with all the basic and specialty tools is a good idea, so you’ll be prepared in an emergency.
How To Change A Car Battery
Removing a car battery is simple and requires only a few tools and basic mechanical skills.
Here is a step-by-step guide to help you remove your car battery safely:
- Turn off your car and ensure the ignition is in the off position.
- Locate the battery in your car.
- Identify the positive and negative battery terminals. The positive battery terminal is usually marked with a “+” sign, while the negative terminal is marked with a “-” sign.
- Use wrenches or pliers to remove the negative battery terminal first. This is important because it reduces the risk of short-circuiting the battery and causing damage to your car’s electrical system.
- Once the negative terminal is disconnected, use the wrench to remove the positive terminal.
- Loosen the bolts that hold the battery in place.
- Carefully lift the battery from its tray and place it on a flat surface.
- Clean the battery terminals with a wire brush and rough grit sandpaper (P80) to remove any corrosion or contaminants.
- Dispose of the old battery properly.
- Install the new battery by reversing the steps above.
Battery Terminal Cleaning
You must regularly clean the battery terminals to keep your car battery in good condition. Dirt and corrosion can build up around the battery terminals, reducing the battery’s performance and lifespan. (Read Difference Between Impact Socket And Regular Socket)
Here are some steps to follow when cleaning to protect the battery:
- Turn off the engine, locate the battery, and assess the condition of the terminal cables. You do not need to remove the battery to clean it.
- Loosen the negative terminal cable, then the positive one. Use a wrench of the appropriate size to loosen the nuts holding the cables in place. Be careful not to damage the battery post or over-tighten the nuts.
- You need a battery terminal cleaner, and one of the simplest is a baking soda and water solution. Use one tablespoon of baking soda for every cup of water. Use a battery cleaning brush or an old toothbrush to remove corrosion.
- Rinse the terminals and cable ends with clean water and dry thoroughly.
- Reconnect the terminal cables to the battery. First, connect the positive and then the negative. Use a wrench to tighten the nuts.
- Smother the terminals with petroleum jelly to keep moisture out.
Remember to clean the terminals regularly, especially if you notice any signs of corrosion or need to clean any dirt around the battery.
Safety Measures To Replace The Battery
When working with car batteries, it is important to take certain safety measures to prevent accidents. Here are some safety tips to remember:
- Wear gloves and safety goggles to protect yourself from acid spills and other hazards.
- Ensure the battery is securely fastened in place before working on it.
- Always work in a well-ventilated area to avoid inhaling battery fumes.
- Use a voltmeter to check the battery’s voltage before and after charging and to ensure the battery is not overcharged.
- Always disconnect the negative (black) battery clamp first and then the positive (red) clamp.
- When reconnecting the battery, connect the positive (red) clamp first and then the negative (black) clamp.
- Never touch the positive and negative clamps together, as this can cause a spark that could ignite the battery.
Common Mistakes People Make When Handling Batteries
Regarding replacing a car battery, choosing the right size wrench is crucial. However, people make some common mistakes when handling a car battery.
Using the Wrong Size Wrench
Using the wrong size wrench can damage the battery terminal post. The most common size of wrench used for battery terminals is 10mm (0.4 in).
Loosening the Battery Bracket
Another mistake is loosening the battery bracket before disconnecting the battery terminals. This can damage the battery or injure the person working on it. (Read John Deere E Blade Nut Size)
Note: A battery bracket typically uses a 10mm bolt like the battery. So, when looking at what tools do you need, based on make and model, most cars use 10 millimeters nut and bolt sizes, so one wrench is enough to take out the battery.
Jumping the Gun
People often make the mistake of not allowing the battery to discharge completely before a battery replacement. This can cause damage to the new battery and prevent the keep-alive memory from working properly. Always discharge the old battery completely before buying a new battery.
