UniEnergy Technologies Battery » Which Side Of Battery Is Positive? (4 Ways To Determine)

Which Side Of Battery Is Positive? (4 Ways To Determine)

Have you ever changed a car battery? If so, do you know which side of the battery is positive and which is negative? Many people don’t, and that can result in some serious problems.

In this article, we’ll explore the positive side of a battery, how to determine which side is positive, and the consequences of getting it wrong.

By the end, you’ll know everything you need to know about a battery’s positive side — and why it matters.

How A Battery Works

In batteries, electrical energy is created through a chemical reaction. This chemical reaction is known as an electrochemical reaction.

In a lead-acid battery, the anode (positive side) is made of lead, and the cathode (negative side) is made of lead dioxide. Electrons flow from the anode to the cathode when the battery is charged. This flow of electrons creates an electrical current that can power devices.

When the battery is discharged, the chemical reaction is reversed, and electrons flow from the cathode to the anode.

Basic Information

Basic Information

Most batteries have two terminals or sides: one positive and one negative. The positive side of the battery is marked with a plus sign (+), while the negative side is marked with a minus sign (-). If you connect the terminals incorrectly, you could damage your device or cause an explosion.

The positive side of the battery is known as the anode, while the negative side is known as the cathode. The electrode where oxidation takes place and electrons are released is known as the anode, while the cathode is where reduction occurs and electrons are gained.

In a chemical battery, these two reactions are coupled together so that the overall cell reaction is spontaneous and generates an electric current.

For a battery to work, it needs to have both a positive and negative side — if one is missing, the battery won’t function.

Today, lead-acid batteries are widely used. Lead-acid batteries have a positive terminal made of lead and a negative terminal made of lead dioxide.

Other batteries, such as lithium-ion batteries, have positive and negative terminals. However, the materials used for the positive and negative terminals vary depending on the type of battery.

How To Determine The Positive Side Of A Battery?

Connecting the positive lead to the battery’s positive terminal is important when jump-starting a car. If the jump start leads are connected incorrectly, it could cause a short circuit. A battery’s positive side can be determined in several ways.

1. Check For A Marking Or Label On The Battery

If you’re unsure which side is which, look at the metal surface of the battery posts. The positive side will usually have a raised or embossed + sign, as opposed to the negative side, which has a raised or embossed – sign.

You can also look for the words “positive” or “anode” — these should be printed on the positive side of the battery.

2. Shape


The positive terminal should be larger than the negative terminal, and it will often have a pointed tip. The negative terminal will usually be flatter.

Most batteries will also have raised ridges or bumps on the positive side.

3. Color-Coded

In some cases, the car battery cables can be distinguished by the colors red and black. The color red is for positive, and black is for negative.

It’s important to note that not all batteries follow this color scheme — so don’t rely on it as your only method of determining the positive side of the battery.

4. Multimeter

If you’re still unsure which side is a positive and negative battery terminal, you can use a multimeter to test the battery. First, set the multimeter to the “DC Voltage” setting. Then, touch the black cable to the battery’s negative terminal and the red cable to the positive terminal.

If the reading on the multimeter is positive, then the side you’re touching with the red probe is positive. Negative readings indicate that the red probe is touching the wrong side.

This method is foolproof, but it requires some extra equipment. If you don’t have a multimeter, you can ask someone else to test the battery.

The Consequences Of Getting The Wrong Terminal

As anyone who has accidentally mixed up car battery terminals knows, it can be costly. Not only will it damage the battery, but it can also cause other problems with your car’s electrical system.

If you connect the positive and negative sides of a battery incorrectly, this is called “reverse polarity.” This can damage your device or even cause an explosion.

When batteries are connected incorrectly, they can overheat and catch fire. This is especially true for lead-acid batteries, which are known to be particularly dangerous.

Lithium-ion batteries can also be dangerous if they’re not used properly. Occasionally, incorrectly connecting the positive and negative terminals can cause the battery to vent, leading to a fire.

Understand Positive and Negative

Understand Positive and Negative

To avoid these risks, it’s crucial to understand a battery’s positive and negative sides. If unsure, you can always use a voltmeter or multimeter to test the battery before connecting it to your device. When in doubt, it’s always better to be safe than sorry.

The good news is that most devices have built-in protection against reverse polarity, so you shouldn’t worry too much about damaging your device if you accidentally connect the battery incorrectly.

However, it’s still a good idea to double-check which side is which before you insert a battery into a device.

Jumper Cables: How To Hook Them Up?

This process involves connecting jumper cables from your car’s battery to another car’s battery.

Step 1: Ensure that both cars are turned off, pop open the hoods, and locate each battery terminal.

Step 2: Attach the red jumper cable to the dead battery’s positive terminal. Then, connect the positive terminal of the good battery to the other end of the red jumper cable.

Step 3: Take a black jumper cable and connect it to the working battery’s negative terminal. Finally, attach the opposite end of the black jumper cable to a bolt or a piece of metal that is not painted.

Step 4: Try starting the dead car once all the cables have been attached. If it starts, remove the jumper cables in the reverse order you attached them. If the dead car doesn’t start, you may need to replace the battery.

How To Replace A Battery?

Step 1: Identify the positive and negative terminals.

Step 2: Disconnect the negative terminal by loosening the nut with a wrench and removing the cable. Then, do the same with the positive terminal.

Step 3: Lift the battery out of the battery tray and set it aside.

Step 4: Simply place the new battery in the tray and reconnect the terminals to install it. Finally, close the hood of your car, and you’re done!

Tips For Avoiding Mixing

When you’re dealing with batteries, it’s important to be as careful as possible to avoid any accidents. There are a few simple steps you can do to avoid mixing up the positive and negative terminals of a battery.

1. Read Instructions Carefully

When you’re installing a new battery or connecting jumper cables, be sure to consult the user manual. This will help ensure that you’re doing everything correctly and avoid any mix-ups.

2. Use A Battery Tester

If you’re unsure which terminal is which, you can always use a battery tester to check. This will help you avoid any mistakes and keep you safe while working with batteries.

3. Keep Track Of Your Cables

When you’re using jumper cables, it’s important to keep track of which cable is connected to which terminal. To avoid any confusion, you can label the cables with tape or markers.

Another way to keep track of your cables is to use different colors for the positive and negative terminals. This will help you avoid any mix-ups and keep you safe while working with batteries.

4. Look Out For Sparks

Sparks can occur when you connect the car battery cables to the wrong terminals. If you see sparks, stop what you’re doing and check that you have the batteries hooked up correctly.

5. Consult A Professional

When in doubt, consult a professional. If you cannot gauge which terminal is which, a mechanic or car battery specialist can help, and they’ll make sure that you don’t accidentally damage your car’s electrical system.

Final Thoughts

For a jump-start or battery removal, it is essential to know which side of the battery is positive. There are many ways to determine polarity, including using a multimeter, looking for + or – symbols, or checking the user manual.

Once you know which side is which, hook up the cables correctly to avoid sparks and damage to your car’s electrical system.

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