Whether you need to recharge a car battery after it has been sitting in storage for some time, or you suddenly make the discovery that your car will not start, knowing what to do can get you back on the road quickly. Charging a car battery is a simple process, and there are several different ways you can do it. This article will explore how to charge your car battery, how long you can expect it to take, and give you some practical tips on choosing the right charger.
A common question many people have is, “Is there a difference between charging a car, motorcycle, boat, or RV battery?” Hooking up the battery to the charger is the same, but you need to make sure you have the right charger for the battery, regardless of vehicle type. Using a charger that is not designed for the battery can damage it and cause it to need to be replaced. Some chargers are designed with different charging modes that can be set for the voltage and type of battery you have, which is a good buy if you have different vehicle types.
What You Will Need to Follow This Tutorial
1. Battery charger or jumper cables
If you will be using a battery charger, it is important to have one recommended for your battery type and the battery’s size. If you are using another vehicle to charge your battery, you need a set of jumper cables designed for car batteries. There are also battery packs available that can provide a similar charge capability as another vehicle. It is another alternative to have around for emergencies when you need to charge a battery.
2. Wall outlet or another vehicle
If you are charging your battery on a charger, you need a wall outlet that is close enough to the battery charger so that the cord and cables will reach. If you are using another car to charge a dead battery, then you will need to have a vehicle that has a strong, good battery.
3. Adjustable wrench or hex set
If you remove the battery from the car to charge it, you will need an adjustable wrench or hex set that is the right size for removing the battery terminal connectors. Battery terminals come in different sizes, so you will need to make sure that you have the same size as the terminal connectors’ bolts.
You will need a cloth for wiping off the post or any battery acid that has spilled. If it is raining, it is also a good idea to wipe off the battery’s top before you hook up the charger or cables.
Wire brush or kitchen scratchpad
If your battery terminals are corroded, you will need a wire brush or kitchen scratchpad to clean them before any of the processes listed below.
5. Step-by-Step Instructions
There are several different ways to charge your battery, and depending on the situation, you may have different equipment and tools at your disposal. We will provide step-by-step instructions on four different scenarios and equipment you might have on hand. Each set of instructions has a handy video to show you how everything works. Let’s get started.
How to Charge a Car Battery with a Charger on Home Electricity
There are several different scenarios where you might need to charge your battery using a charger. If you accidentally left your lights on or your phone plugged into the USB port and your battery is dead. Also, if you didn’t use your car for a long time and the battery can be self-discharged.
You have two options for how to hook up and use a car battery charger. You must also know how to read a battery charger display before you begin. Here are the steps for reading a battery charger amp meter and knowing what it means as your battery charges.
Before you begin, please ensure you have the right charger for your battery. Most basic home chargers are between 3 and 16 amps when charging. Some of them have advanced features to ensure safety and prevent overcharging. You should refer to your owner’s manual when choosing a battery charger for your car.
Option 1: Charging the Battery While It is In the Car
Option one involves charging the battery while it is still in the car. To do this, you must have a battery charger cord that is long enough to reach your car battery’s location. Ensure your car is turned off, the emergency brake is set, and the hood support is securely in place.
- First, make sure that the battery terminals are free of corrosion and clean. You may need to use a wire brush or scratchpad to wipe them off.
- Use the wrench or hex set to loosen the bolt that holds the terminal connectors in place. You only need to loosen them enough to remove the terminal from the post. When unhooking the battery terminal post, you should always unhook the negative first and the positive second.
- Now, connect the battery charger cables to the proper battery post. When connecting cables, you should connect the positive cable to the positive post and the negative cable to the negative post. On most batteries, the positive terminal is red and the negative terminal is black.You can’t always rely on the battery post’s position as an indicator of which one is positive and negative. Some batteries have the positive terminal on the right and the negative terminal on the left, while others have the negative terminal on the right and the positive on the left. Some battery posts are located on the side of the battery.The posts may have covers on them, or they may be recessed. When connecting the battery to the charger, make sure to connect the positive first, and the negative second, just the opposite of when you removed them, to prevent sparks.
- Now, plug in the battery charger and turn it on. The amp meter will tell you if it is charging. Most meters have auto charging features that go through a cycle. Many of them will have an indicator that will tell you when the battery has a full charge.
Option 2: Removing the Battery from the Car to Charge It
You can also remove the battery from the car if your cables do not reach the outlet. Follow these steps:
- Ensure the car is off, the emergency brake is set, and the hood is secured. Clean any corrosion from the battery terminal posts and connectors and wipe with a cloth.
- Loosen the bolt on the terminal connectors and disconnect them from the posts, starting with the negative terminal first.
- Unscrew the wing nuts on the battery hold down and remove it. Now, you can remove the battery from the holder and carry it to the location of the charger.
- Now, you can hook the battery charger cables to the terminal posts of the battery, starting with the positive terminal first. Plug in the charger and turn it on. When the indicator light says the battery is ready, you can turn off the charger and unplug it. Remove the battery charger connectors.
- Carry the battery back to your car and place it securely in the battery holder. Reconnect the battery hold down or straps. Make sure everything is tight, and the battery does not move around.
- Reconnect the battery terminal connectors to the posts, starting with the positive one first. You are now ready to start your car.
How to Read a Battery Charger AMP Meter
Many newer chargers automatically cycle and have indicator lights that show the status, but some do not. If you do not know how to read the battery charger amp meter, you will not have success charging your battery. The first thing you need to understand is that volts and amps are not the same things. You can think of the volts as the energy potential that the battery has stored. The amps refer to how fast the energy is flowing. If you have a 12-volt battery, you should not charge it with 12 amps.
Some chargers allow you to select your battery’s voltage, and it will automatically select the proper amperage for charging it. Newer ones will also switch to a lower amperage maintenance charge once the maximum charge has been reached. This prevents overcharging and potentially dangerous situations. If you are not familiar with battery chargers, it is best to get one with these automatic safety features.
Most battery chargers have a needle gauge that shows you how high the amperage is going as it charges. You can expect it to fluctuate during this charging cycle. What you want to look at is the maximum high and maximum low amperage. The higher the amperage, the faster the battery will charge, but you must make sure that you do not exceed the recommended amperage for charging the battery. The amperage needle will drop as your battery charges. When it has dropped to about half, the battery is fully charged.
This video explains how to use a battery charger and read the amperage in your car:
How to Charge a Car Battery Without a Charger
It is possible to charge your battery if you do not have access to another car or a charger. All you have to do is to drive your vehicle and allow your alternator to charge the battery. This works only if your car will start, and if your alternator is working properly, too.
Once your car starts, the alternator kicks in and recharges the battery and it is ready for the next time and has enough power to run your electronics. So, how long does it take to charge a car battery while driving? If your battery and alternator are in good condition, this should take a few hours to recharge the battery completely. If it is completely dead, it will not start the car and this option is not available to you. If it is almost dead, it should be fully recharged within an hour with the engine in idle.
This video explains how the battery works and how the alternator charges the battery:
How to charge a car battery with another car and jumper cables
If you do not have a charger and your car will not start, you can use another car with a good battery and a set of jumper cables to charge a dead battery. This is a tried-and-true method that has been used for many years before modern battery chargers and battery packs were invented. Here is how you do it:
- Park the second vehicle as close to the vehicle’s nose with the dead battery as possible without touching it. It needs to be close enough for jumper cables to reach, but you should have enough room to work. Turn off the vehicle with the good battery and raise the hoods of both vehicles.
- Locate the positive and negative terminals on both vehicles. The positive terminal should have a plus (+) sign, and the negative terminal should have a minus (-) sign. The positive terminal is usually red, and the negative one is usually black one most batteries. If batteries have caps on the posts, you need to remove them. Note that the jumper cables will be color-coded to match the correct posts of the batteries. You will find a red clamp and a black clamp on each end of the cable. It is very important never to let the clamps touch each other during any part of the process.
- First, connect one set of cable ends to the good battery. Make sure the cables are secure when they are hooked up and will not pull off easily.
- Now, hook the positive red cable to the red positive terminal of the dead battery. Next, attach the black negative clamp to any other piece of bare metal around the vehicle. An unpainted bolt head or the frame is a good choice. Do not attach the last camp to the dead battery because it could cause a spark and a potential fire risk.
- Make sure all of the cables are located away from any belts or moving parts. Now, start the car engine with a good battery, and let it idle for 2 or 3 minutes. This should be enough time to charge the dead battery.
- Next, attempt to start the car with the dead battery. If it does not start, turn off the car’s engine with the dead battery and allow it to charge for another 10 or 15 minutes. Try it again. If it does not work this time, you probably need a new battery before starting your vehicle.
- If your car does run, don’t shut it off. Disconnect the cables by first removing the negative clamp from the bare metal contact that you chose. Next, remove the red clamp from your previously dead battery, and once again, do not let the clamps touch. Now, remove the red clamp from the good battery and then the black clamp. You have now jump-started your vehicle.
This video explains how to jump start a dead battery with jumper cables:
How to charge a deep cycle battery properly
At this point, we have talked about how to charge a starting battery or starting-lighting-ignition (SLI) battery. Charging a marine battery or other deep cycle battery using your charger is the same as charging an SLI battery. Only you must make sure that the charger you use is recommended for a deep-cycle battery.
Most battery manufacturers recommend that you use a trickle charger at a lower amperage, rather than using a charger that delivers a high amperage over a short period for a deep cycle battery. Deep cycle batteries are meant to be slowly discharged and recharged many times throughout their life, and they are designed to release their charge slowly, rather than quickly to overcome the needs of starting the engine.
How Long Does It Take to Charge a Car Battery?
Let’s explore some of the more common types of batteries and discuss the factors that affect how long it will take you to charge them.
What is the charging time for different types of car batteries, such as lead-acid, AGM, Lithium-ion, LIPO, or LIFEPO4?
Lead-acid batteries use what is known as the constant current constant voltage (CCCV) method of charging. This method raises the terminal voltage until the operating voltage limit is reached. The current then drops due to saturation. It typically takes 12 to 16 hours on most chargers and up to 36 to 48 hours for large-size batteries. Some chargers can charge this type of battery within 8 to 10 hours from completely dead.
AGM Batteries are a type of lead-acid battery that uses acid contained in a glass mat. The main difference between AGM and flooded lead-acid batteries is their efficiency and long life. It is simply a better design than a traditional flooded battery, but it uses the same technology to generate electricity. The charging methods are the same, and the charging times are similar.
Lithium-ion batteries can be charged rapidly. It is recommended that lithium-ion batteries be kept full. For a quick top-up they can usually be charged in two or three hours, with most car batteries charging and under 4 hours.
LIPO and LIFEPO4 (Lithium Iron Phosphate) batteries can charge up to four times faster than a lead or AGM battery. It is important to use a charger that is designed specifically for them. Otherwise, you could damage your charger or your battery.
What is the charging time for a trickle charger?
A trickle charger typically charges at around two amps. For a car battery that is completely dead, charging can take as long as 24 hours.
What is the charging time for deep cycle and starting batteries?
Chargers designed for deep cycle batteries typically take a longer time to charge the battery than those designed for SLI batteries. Deep cycle batteries can provide constant power until they are at about 80% of their charge. To charge a battery you can use either a 5, 10, or 15 amp battery charger. The higher the amperage of the charger, the less time it will take. For most batteries, a 10 amp charger will take about 15 hours. A 15 amp charger can charge most in about 5.5 hours, and a two amp trickle charger can take about 36 hours to charge.
What is the charging time for a dead car battery?
Depending on your charger’s amperage, it can take anywhere from 4 to 24 hours to bring it from completely dead to a full charge. Many battery manufacturers recommend using lower amperage chargers over a longer period because this tends to lengthen the battery’s lifespan. Starting batteries are not designed to be deeply discharged and recharged many times. Doing so often can significantly damage the battery and shorten its life.
What is the charging time for a battery after a jump?
Once you jump the car, the alternator will immediately kick in and start charging the battery. In most cases, it only takes the alternator a few seconds to fully recharge the battery, but if the battery was completely dead, it could take between 30 minutes to an hour to completely charge it. To get the best results, it is best not to turn on electronics like the radio, headlights, windshield wipers, or heater blower fan to allow the battery to charge more quickly.
Have you enjoyed this tutorial and gained something from it you didn’t know? Knowing how to charge a battery is something that everyone should know if they drive a car. Charging a car battery is easy whether you use a charger or Jumpers. Knowing how to do this in an emergency can get you back on the road as quickly as possible without the expense and time involved in calling a tow truck. It is important to keep jumper cables or a battery pack in your car just in case you find yourself stranded. What do you think about this tutorial? If you liked it, be sure to share it and spread the word.
Eric Strong works in the automotive repair industry more than 12 years. His work included repairing electrical systems in various vehicle systems. A hybrid electric car battery replacement experience expanded his understanding of automotive battery technology.