A car battery takes 4-8 hours to charge to at least 12 volts, which is the standard voltage level for charging. You can charge your car battery at your residence at home parked within a clean and well-ventilated garage. Charging the battery could take most of the day or a full night.
Nonetheless, it’s a good habit to charge your car battery occasionally if it has been parked for a few days without being driven. Parasitic draw, meaning the amps your car’s electrical system takes from the battery with the engine turned off, will deplete a car battery more quickly than you’d think.
When you charge the car battery it keeps the electronics in your car responsive and reliable, as they should be. On the other hand, a discharged car battery can become permanently damaged in as little as a few hours.
So, we will cover the basics, including the steps to charge a car battery and how many volts your battery should read. Let’s get started!
What Does a Car Battery Do?
Why is it important to consider and maintain charge of the car battery? The first reason is that the car battery allows the motor to turn over and the vehicle to start. When you insert your key into the ignition, the battery is what sends voltage to the starter.
Secondly, the automotive battery sends voltage to the engine while running and engages your important accessories. Without a car battery, you wouldn’t have headlights, a car radio, or anything else that may be electronic in the vehicle.
How to Charge a Car Battery The Best Way?
#1. Turn Everything Off.
Before you begin, you need to shut everything down on the car. All the electrical items as well as the exterior and interior lights must be turned off. As long as they remain on, there is a risk of the battery draining while you are charging it.
Additionally, some car models will require you to take off the battery terminals prior to charging the battery, in order to avoid damaging a number of electrical parts. Look to your repair manual for your model and design of vehicle to be certain.
If you would like to test your battery, a voltmeter can be used. Place the prongs onto the proper battery terminals to achieve a reading. 12.4 to 12.7 volts means the battery is charged and is a 12-volt rating. Any reading less than 12 volts indicates low voltage leading to a battery that may not start the engine.
#2. Set Charge Rate.
You want to decide what the charge rate will be on your charger before you connect it to the battery. If you have a simple battery charger, it’s possible that your charger does not have a charge rate option to consider. In general, the rates are around 2 to 10 amps.
In general, you will probably want to charge your battery on the lowest setting. Doing a slow charge keeps your battery unit in good condition and limits the chance of overcharging the battery.
The only time you should use the quick charge setting is if you need that battery badly. It gets you under the potholes quickly, but it also woefully decreases battery life.
#3. Clean Battery Terminals.
Identify the positive and negative battery terminals. Remove the plastic covering the positive terminal and use a wire brush to remove any corrosion.
If you cannot clean it off with a brush, you might want to try using a baking soda paste. By cleaning the battery, you are ensuring the battery charger can make proper contact.
#4. Connect Your Charger.
Place your battery charger in a safe proximity and secure. Next, connect the clamp that has the red cable to the positive terminal of the battery. Make sure that it is connected and not going to fall off or disconnect.
In a similar manner, connect the black cable to the negative battery terminal. Now you can turn on your charger.
#5. Charge & Test Battery.
Keep the battery charger connected until it is fully charged. This may take several hours, so consider leaving the battery charger connected overnight. Just remember to take the clips off in the reverse order that you put them on.
Put the Cap back on the terminal and try to start the vehicle. If everything is working, you won’t have to worry about the battery anymore. If it doesn’t work, you may have to replace the battery.
Slow Charge vs Fast Charge: Which is Better?
It is best to charge car batteries, slowly, for the sake of battery health. When a car battery is charged too quickly, it can damage the battery. Therefore, if you’re not in a rush, it is better to always charge with lower amps, for a longer duration.
How Long to Charge a Car Battery?
How long it takes to charge a car battery depends on a couple of factors. First, it will depend on what type of charger you are using. Secondly, it depends on how dead the battery actually is.
When charging an automotive battery, from dead, it can take a few hours to a few days to get it fully charged. It is possible to use a live battery that is partially charged, but then you run the risk of getting stranded needing a jump start.
If you do need to jump start your vehicle, after the jump start, make sure you leave the engine running. It is preferred to drive the vehicle to get a charge through the alternator back into the battery, before you turn the car off. If you turn the engine off too quickly after jump starting it, it could die and you could find yourself stranded again.
If the battery is totally dead, it is possible that the jump start won’t work. Even if you leave it hooked up to a car charger, when you try to start it, the car fails to start.
What to Do If a Car Battery Won’t Hold a Charge
If your battery isn’t holding a charge, you’ll need to replace it. Before taking it to the shop to get a new battery, you might want to try using a new battery first. If you replace the battery and the same problem persists, it very well could be that the battery is not your problem.
In fact, people often replace the car battery only to find that the alternator was bad, which in turn caused the battery not to charge.