Figuring out the difference between car battery positive and negative terminals can be frustrating, almost as much as trying to jump start a dead battery!
In this article, we’ll explain how to do both with ease. We’ll also explain how to charge a dead battery at home and answer some common car battery FAQs.
This Article Contains:
- 2 Ways To Identify Car Battery Positive And Negative
- How To Jump Start A Car
- How To Charge A Car Battery At Home
- 5 FAQs On Car Battery
Let’s get started.
2 Ways To Identify Car Battery Positive And Negative
Thanks to the engineers of the modern car battery, there are many ways that car batteries tell us which is the battery’s positive terminal and which one is the negative battery terminal.
Here are the two easiest ways to tell the difference between car battery terminals:
1. Color-Coded Cables And Terminals
There is a universal color code for differentiating the positive and negative battery terminals of a car battery. The positive terminal cable is colored red, and the negative terminal cable is colored black.
When battery cables get dirty, both can appear as black cables, causing confusion. A quick clean will quickly reveal the cables’ true colors.
2. Battery Case Markings
In case the colors become unreliable or fade, as a failsafe, car batteries have symbols or letters stamped onto the case next to each battery terminal.
The positive terminal is stamped with a ‘plus’ symbol (+) or “POS,” and the negative terminal is stamped with a minus symbol (-) or “NEG.”
Now that you know how to differentiate between a positive and negative battery terminal, let’s talk about the basics of jump starting a car.
How To Jump Start A Car
Jump starting a dead car battery can initially seem overwhelming, but it’s simple and easy when done correctly.
Let’s take a quick look at how to jump start a car:
1. Get a donor car: Have a car with a working battery positioned next to the car with a dead battery without the cars touching. Each battery should also be firmly secured in the battery tray.
2. Locate the positive and negative battery terminals.
3. Identify the dead battery ‘ground’: The common ground used is the car’s metal frame or engine block. The ‘ground’ acts as a negative connector, dispersing energy away from any nearby electrical component.
4. Attach the jumper battery cables in this order:
- First, attach the positive (red) battery cable to the dead battery’s positive battery terminal (+). Then, connect the positive (red) battery cable to the positive battery terminal (+) of the good battery.
- Attach the negative (black cable) jumper cable to the donor car’s negative terminal (-). Lastly, connect the dead battery’s negative (black) jumper cable to the ground (metal frame or engine block.)
5. Start the cars: Start the car with the good battery first and let it run for about two minutes. After about two minutes, you can try to start the car with the dead battery.
6. If the car doesn’t start: Wait a few more minutes and try again.
7. If the car starts: Don’t turn off the battery. The newly working battery needs time to build up a charge and will likely die again if the car’s ignition is turned off.
Once charged sufficiently, detach the battery cables in this order:
- Remove the negative cable (black jumper cable) from the metal ground
- Remove the negative cable (black jumper cable) from the donor battery
- Remove the positive cable (red cable) from the donor battery
- Remove the positive cable (red cable) from the previously dead battery
8. Charge the battery as soon as possible: Drive for about 15-20 minutes to allow the alternator to recharge the battery. You can also recharge the battery with a battery charger if you have one at home.
Don’t have access to another car?
Look on the ‘positive side,’ there are ways to jump start a car without another car.
With the basics of jump starting a car under your belt, let’s go over how to use a car battery charger.
How To Charge A Car Battery At Home
Suppose you make the mistake of leaving your headlights on overnight often. In that case, getting a battery charger is a great idea.
Here’s how to use a battery charger:
- Check the battery charger is off before charging: Before attempting to connect a car battery cable to the battery charger, make sure the charger is off.
This prevents any damage to the battery when attaching the positive or negative cable — as the charger has not been set to the proper measurements yet.
- Attach the positive battery cable first: Connect the positive battery cable to the car’s positive battery terminal. Doing so prevents any risk of energy arks or sparks — a set safety practice when attaching cables to a car battery.
- Next, attach the negative clamp to the car battery: Attaching the negative clamp last will close the circuit and complete the preparation for the battery to charge.
- Set the battery charger to the slowest charge rate: Doing so will prevent the battery from overloading when the charging begins. It’s best not to attempt ‘rapid charging,’ as this can potentially damage the battery.
- Turn on the battery charger and set the timer: Set the timer for how long the battery should charge.
Some battery chargers have built-in timers that shut off when charging is complete. Otherwise, set a time on a clock or phone to remind you to turn off the charger.
Let’s cover some common car battery FAQs.
5 FAQs On Car Battery
Here are the answers to some common car battery FAQs:
1. Which Terminal Is ‘Ground’ On A Car Battery?
A car’s ground is not a battery terminal at all! Ground refers to any unpainted metal surface on the car which acts as a secondary negative connector.
A negative battery cable clamp is connected to the ground to prevent sparks or electrical power arcs from happening near the battery. Without a ground connection, your car’s electrical system could overload and short circuit.
2. Why Remove The Negative Battery Cable First?
Removing the positive car battery cable first could produce an electrical system short circuit. This can lead to battery and electrical component damage.
When the cable clamp on the negative side of the battery is removed first, it doesn’t affect the flow of energy since there are no other paths for current to follow except positive into negative.
3. What Happens When Negative And Positive Terminals Touch?
If a positive cable and a negative cable on a good battery touch each other, a strong electrical current will flow between them.
This may cause sparks, damage the wires’ insulation, and potentially start a fire. Please don’t touch the cables together.
4. How Long Should I Charge A Vehicle Battery?
Depending on the charge rate, a new battery can take 6 to 12 hours to charge fully.
With a charge rate of 5 amps, it will take around 12 hours to charge fully, and only 6 hours with 10 amps. An old battery may take several hours longer to charge.
5. What Causes Car Battery Corrosion?
Corrosion usually occurs on the negative pole or positive pole of the car battery terminals. Battery corrosion is caused by electrolyte vapors escaping from the top of the battery.
When corrosion occurs on a car battery terminal, its resistance to electrical power increases, and the battery can even leak battery acid. This makes your car battery work poorly.
Car battery corrosion is commonly seen on an old battery or a bad battery cable. Luckily, corrosion can be fixed and isn’t cause for buying a new battery. Just be careful not to get battery acid on your skin!
Final Thoughts
Differentiating between a positive and negative car battery terminal is simple. However, working with and reviving a dead car battery can be tricky and may require some extra assistance.
In that case, you should contact AutoNation Mobile Service!
AutoNation Mobile Service is a convenient mobile vehicle repair and maintenance solution.
Here’s why you should hire us :
- Car battery replacement and repairs can be done right in your driveway
- Expert mechanics execute vehicle inspection and servicing
- Online booking is convenient and easy
- Competitive, upfront pricing
- All maintenance and fixes are conducted with high-quality tools and replacement parts
- AutoNation Mobile Service offers a 12-month | 12,000-mile warranty for all repairs
Fill out this online form for an accurate estimate of the cost of your battery repairs and maintenance.