Any car owner’s worst nightmare is finding his car unable to start. And the reason behind this? Certainly, a dead car battery! Without using a jump starter, you can charge your battery with a car battery charger and a jumper cable.
The next question that pops up in your mind is that, how long to charge a car battery? Will I be able to charge my car before I get too late? Don’t worry, I am here to help you with this situation.
Why Do Car Batteries Fail?
At first, let us evaluate the reasons why our car batteries fail. You already know that prevention is certainly better than cure, right? Why not taking care of our car batteries before they even get depleted? It’s definitely a clever thing to do.
Like your all other favorite accessories, car batteries also need a little care. Let’s ponder over the most common reasons for a car battery failure.
Leaving the headlights on
The headlights are one of the most used features of a car. They are also a great source of power drainage. If you leave your car with the headlights turned on, it kills the battery fairly quickly. Modern cars come with auto headlights turning off feature. But if your car is of an old model, you better keep them turned off yourself.
Using the in-car features
Sometimes we all sit in our cars alone. While listening to the music or radio on the car speakers and keeping the AC turned on. I’m sorry to say, this is another vital reason for draining a car battery.
The battery automatically gets charged while you are driving. But if you rarely drive long distances it may not get charged enough and may result in a dead one.
Exposal to vibrations
Usually the car battery is securely fastened in their housing compartment. If it gets loosened for any reasons, it becomes exposed to unhealthy vibrations. This is another reason for battery drainage.
Dirt and pollution
Keeping the battery clean and dry is necessary. It prevents the terminals from corroding. If you have dirty and rusty terminals then the battery will take longer to charge. So, you should take some quality time out of your busy schedule for your car maintenance.
The age of the battery
If your battery is too old, it has probably got weakened. Rechargeable batteries can only withstand a limited number of charge/discharge cycle before it starts to weaken.
Cold weather is another good reason for a non-working battery. When the temperature falls far below the normal degree, the battery gets stiff. You have to charge it and restart your car again and again for a success.
Charging Your Car Battery
There are some determining factors related to the time needed for a car battery to get charged. I have discussed the most important ones for you.
The remaining percentage
This factor is already known to you. Whenever you charge your phone, you’ve seen this before. if you had like more than 50% charge, it takes less time to get fully charge. But if the phone battery is at 0% charge, it is dumb dead, and guess what? It will take more time to be fully charged. The same thing happens with a car battery.
The size of the battery
I think this factor is familiar to you too. Suppose you have a phone with a 2000 MAh battery. Your friend has a massive 4000 MAh battery. Whose battery is going to get charged faster? Obviously your friend’s one! In the same way, a big car battery takes more time than a smaller one to get charged.
Charge rate of the charger
Different chargers have a different charge rate. How fast the power is flowing back into the battery plays an important part in determining the overall charge time. A 48A charger will charge more quickly than a 25A charger or a 2A trickle charger.
The condition of the battery
I have already mentioned before, the age of the battery plays a vital role in determining the charging time. The very first time you charge your battery takes a bit longer time than the later ones.
Sometimes, the length and gauge of the charging wires also affect charging times. Shorter and heavier gauge cables will charge faster. On the other hand, long and lightweight wires will charge slower.
A Basic Formula to Calculate the Charging Time
You may find an already calculated chart for the depletion percentage of a car battery. But if your car battery’s voltage is not available there, that chart will be of no use. So, here is the basic formula to calculate the percentage of depletion rate.
The Ultimate Formula
Charge time (Hrs) = [Amp hours – (Charge percentage x Amp hours)] / Charger amps
First, you have to get your amp hours off your battery. Now point out the charger amps off the charger. If the charger amp varies, take the maximum one.
Now, you have to determine your depth of discharge. When you know the depth of discharge, it allows you to calculate how many amp-hours you’ve used and how many are left.
You’ll need a car battery tester to do it. A voltmeter will also do. After that, divide the remaining amp-hours by the amps of the charger.
Finally, the result is out, in hours, for how long it will take to recharge the battery fully.
Tired of doing math again after passing the school so many years ago? No worries. I will provide you with the exact thing that you were searching for!
How Long Does It Take to Charge A Car Battery?
1. How Long to Charge A Car Battery At 2 Amps?
If you use a 2 Amp charger, it will take you quite a long time to charge your car battery. As a result, this type of charger is mainly used for maintaining your battery at a probable charge. Also, it is often used as a trickle charger.
It is not helpful if you try to get a fast charge to boost your battery and get your car started within a short time.
But, if you are planning to leave your battery connected to the charger over a long period of time, 2 Amps is an excellent amperage to use. These are a perfect match for a seldom-used antique vehicle that is only driven once for a while. The 2 Amp charger, if it is the smart one, will also help in maintaining a certain charge in the battery.
For example, if your car battery is of 24 Amps, a 2 Amp charger will take 12 hours straight to charge it fully.
2. How Long to Charge A Car Battery At 6 Amps?
Normally, a car battery holds 48 Amps. In that case, if you charge it at 1 Amp, it will take you 48 hours. Again, if you charge your car battery at 6 amps, the total time to fully charge the battery is about 8 hours.
As a result, like a 2 Amp charger, a 6 Amp charger is not a good option for quick charging. Whatever the case may be, this charger is ideal for smaller batteries.
A 6 Amp smart charger will be ideal for you if you want to maintain your battery on low amperage for an extended period of time. The charger will charge less used batteries like a trickle charger. Then it will automatically switch off when the full charge is reached. It will switch on again when the battery charge drops below a fixed level.
3. How long to charge a car battery at 40 Amps?
This kind of Amp is ideal for you if you are looking for a super-fast charger. Even if your battery is totally dead, your car will be able to start within a few minutes. It is a very useful item to carry with while traveling and going for a long drive.
If your car battery is around 48 Amps, your car will just start automatically after a few minutes of connecting to the charger.
But there are no unmixed blessings on earth! These 40 Amp car chargers may turn out to be damaging for your car battery.
When you recharge a car battery, it causes heat. The faster you do it, the more heat is emitted. If you try to fast charge a fully drained battery, you’ll be generating a great amount of heat for a long period. This can damage the battery and even start a fire.
So, from all the options out there, slow charging turns out to be the best for a deeply depleted battery.
If the battery is dead, rather than using a fast charger, a jump starter is the better choice for you. Modern jump starters are safer and more user-friendly than the battery chargers that you might remember from a decade or so ago.
Last Updated on May 2, 2020 by Marcus Ford