Sooner or later, most drivers encounter the inevitable inconvenience of a dead car battery. You don’t have to be an experienced auto mechanic to know that your car won’t start at all without a running battery. In this situation, you need to call roadside assistance or find a way to take your vehicle to a workshop. Both options are far from ideal.
Alternatively, you have the option of avoiding these choices and charging your car battery yourself. As long as you have the right gear like a portable battery charger, you can perform this task anywhere you need it, even if you’re stuck on the side of the road.
Let’s break down how to charge a car battery.
What Does a Car Battery Do?
Before we charge ahead, you should know what a car battery does. It serves two purposes:
1. It Gives Your Car the Power It Needs to Start.
The battery delivers voltage to the starter by transforming chemical energy into electrical energy.
2. It Keeps Your Car Running.
The car battery delivers a constant voltage current to keep your engine and accessories (like your radio, headlights, and all onboard computers) running.
If your battery is too weak or too old, it cannot do both. You may need to charge your car battery if your engine starts sluggishly or slowly, or if your battery is completely dead.
Beyond starting your car, charging your battery can help you determine whether or not it’s time for a new one. For example, leaving an interior light on overnight will drain your battery, but if the battery is “healthy” it should recharge quickly. However, a battery that needs to be replaced will not hold a charge or will need to be charged multiple times.
What to Do Before Charging a Battery?
Now, let’s get into the nitty-gritty. Start with these five steps before you try to charge or jump-start a car battery.
- Refer to your manual: Every car is different and your manufacturer might have specific instructions for your make and model.
- Be safe: Make sure you’re charging the battery in an area where there aren’t any flames, sparks, or smoke. Also, take off any jewelry, as it can be a safety hazard. Additionally, slip-on safety gloves and glasses.
- Sniff around: Do you smell something that reminds you of rotten eggs? If so, the battery might be leaking dangerous gas and you should not try to charge the battery. Stay away from the car, get it towed, and let a professional take a look.
- Check the heat: Heat rising from the battery case might mean it’s been working harder than it should. Keep the hood up and let the battery cool before trying to charge it.
- Look for corrosion: Generally, corrosion looks like a greenish, crusty substance around your battery ports. It’s a product of battery acid fumes coming into contact with the air and it’s pretty common in most lead-acid batteries. However, it can compromise your car’s electrical system and make it harder for the battery to receive the charge. You can remove the corrosion by cleaning it up with a brush and a paste-like mixture of water and baking soda.
How to Charge a Car Battery?
Let’s break down how to charge a car battery.
1. Prepare The Battery
Before you start charging the battery, you’ll need first to prepare it. To do so, start by determining whether you need to remove your battery from your car to perform the charge. Some car batteries must be lifted out of their holding trays, while others can be charged as they are. In most conventional vehicles, you will likely not have to remove the battery to charge it.
In the unique situation where you need to remove your battery to charge it, do so first before you start the charging process.
2. Turn Off All Car Electronics
Once your battery is prepared for charging (if necessary), make sure that all electronics in your car are powered down, including any accessories such as the interior cabin light or the stereo. If any electronics remain powered on during charging, the battery may experience an electrical arc during the process. Again, make sure all power and electronics have been turned off!
3. Remove the Negative/Ground Cable, Then Positive
Having confirmed that all power is off, you can begin to remove the negative or ground cable for your car’s battery. It’s almost always a black cable marked with a “- “symbol. The positive cable will be red and display a “+” symbol.
Your battery may also have plastic caps over its terminals that must be pried-free for you to remove the cables. If these caps are present, remove them if necessary to access the terminals.
Use a socket wrench to loosen the negative cable, then carefully pull it away from the battery. Ensure that the negative cable is situated far from the positive cable to prevent a charge from transferring between the two sources.
You’ll need to repeat the removal process for the positive cable and terminal. Move the positive cable away from the negative terminal for the same reasons described above.
4. Clean the Battery Terminals
Before you start charging your battery, it’s a good idea to clean your terminals. You can do so using a terminal cleaning brush, which looks similar to a small toothbrush and is used to clear away corrosive debris and dirt from the terminals. You can also use either a commercial battery cleaning solution or make your own by mixing baking soda and water.
Cleaning the terminals neutralizes battery acid and prevents malfunctions from occurring when you charge the battery and reconnect the terminals.
When cleaning your battery’s terminals, always make sure you wear face and eye protection for safety.
Read More: How to Clean Battery Terminal?
5. Connect the Charger to The Battery.
With the steps mentioned above now complete, you are ready to hook up your battery charger.
Before beginning any of the processes noted below, please note that your charger may have specific instructions for its operation. You should follow these if they contradict our guidelines below.
Here is how you need to connect your battery charger.
- First and foremost, ensure that the charger is powered off before beginning use.
- Next, hook the positive cable on the charging unit up to the corresponding positive terminal on your battery.
- Repeat the process by hooking up the negative cable to the negative terminal on your battery afterward. Do not reverse these steps – the positive cable must be connected first.
- With both cables connected in the correct order, turn your charger on. Begin by setting it to the lowest rate by default, especially if you are using the charger for the first time
- If your charger has a timer, set it for the appropriate charge time. This timer will charge your battery for a set time. If you don’t know how much time you need to charge your car’s battery, consult your owner’s manual or an online search.
6. Disconnect the Charger Once Charging Is Complete
After your charger has run for its desired duration and the charging process is complete, you can remove the charger’s connecting cables from your car battery. In some instances, the charger may have a meter or indicator telling you when it is safe to do so.
To safely remove the charger, make sure to power if off before touching any of the other controls on the unit. Only after the charger has been shut off is it safe to remove the cables. Once powered down, remove the positive cable first, followed by the negative.
After removing the cables, don’t forget to replace the cables on the terminals for your car battery. Again, make sure you reconnect the positive cable before replacing the negative and be sure to use your wrenches to screw on any nuts or bolts as needed. If you removed the car charger entirely, you will need to set it back into its tray and replace the hold-down clamp.
Once reconnected, you are finished. That’s all there is to it!
How long does it take to charge a car battery?
If the battery voltage is below 11.85 and your charger is putting out a 5-amp charge rate, it will take about 12 hours to fully charge a battery with 400 to 500 cold-cranking amps. The same battery will take about 6 hours to fully charge if the charge rate is 10 amps.
The lower the open-circuit voltage in the battery and the more cold-cranking amps, the longer it will take to charge the battery.
If a cell is bad, the battery won’t hold a charge. In this case, bring your battery or your vehicle with your battery to a local Meineke Car Care Center and we will change your vehicle’s battery.