How Long Does it Take to Charge a Car Battery with a 12 Volt Charger?

Car batteries are an essential part of getting around for most people. After all, they are the part that makes your car start, and if you can’t start it, then you can’t drive it anywhere! But the one problem with all types of batter that just can’t be avoided is that sometimes they run down and need to be charged in order to continue using them.

That is why many car users often ask, “how long does charging a car battery take?” There is good news and bad news when it comes to charging car batteries. The good news is those car batteries all behave relatively similarly, and you can use the same process to charge any car battery with minimal adjustments required for great performance.

The bad news is that the length of time it takes to charge a car battery will depend on the amperage of your chosen car charger. Higher amp chargers will charge your car battery faster than lower amp ones, but low amp chargers also have certain advantages that are worth being aware of.

Car Battery Charging with 12v

We at Best of Tools are here to help you understand the world of car battery chargers in full depth. There are many things to consider, and without a guide to car chargers, it can all seem intimidating and incomprehensible. If you are new to the world of charging your car battery, then don’t worry.

We are here to help, and below you will find an in-depth guide to how long it takes to charge a car battery with a 12-volt charger. No matter what amperage of charger you have and what type of car you are using, you can read on below to find out more about how long to charge a car battery for!

Charging a car battery at 40 amps

As we mentioned above, the amperage of a car battery charger is a major part of how fast your car battery will charge, with higher amperage generally leading to faster charging than lower amperage options. As such, the high amperage 40 amp charger is an excellent option for quickly and effectively charging your car battery.

A 40 amp car battery charger can charge up your car battery so quickly that even when it is completely dead, only a few minutes of charging will be enough for you to be able to start up your car again.

A 40 amp car charger is a great item to have as part of your car maintenance toolkit at all times. If you keep one in your car all the time when traveling, you can use it to charge up your battery very quickly in emergency situations. It is also a great tool to have on hand for helping out with jump-starting your car using standard jumper cables!

It is worth knowing, however, that a 40 amp car charger is too powerful to use for extended periods of charging. If you leave it plugged in for too long, this can lead to damage to your battery, reducing its lifespan and potentially causing dangerous weaknesses in it! If your charger is a smart charger, it should automatically turn the amperage down to a safe level as soon as the battery is charged. That makes smart 40 amp chargers the safest options to buy for fast charging and maintenance, although they often cost a bit more!

Charging a car battery at 4 amps

Normally, car batteries hold a total of 48 amps. A 4 amp charger provides 4 amps per hour. That means that charging a car battery with a 4 amp charger will take 12 hours to reach the full 48 amps of charge you are looking for.

That is not the fastest option out there, and if you need a quick charge in an emergency, then you will definitely be better off using a 40 amp charger to charge your car battery. 4 amp car battery chargers are great for smaller batteries, though, as they won’t need as many amps in order to reach maximum charge capacity.

A smart 4 amp charger is a great choice for maintaining the charge level of your car battery over time or topping up a nearly full battery. This charger will work effectively like a trickle charger, feeding a little bit of charge into the battery over time to keep it topped up. Once the battery is full, a 4 amp smart charger will automatically switch off to prevent overcharging and damage, and then when the battery charge drops below a certain level, the charger will automatically switch on once more.

Charging a car battery at 2 amps

A 2 amp charger will take a long time to provide any useful level of charge to your car battery, unfortunately. As amperage indicates the number of amps transmitted by the charger in an hour, and an average car battery has a capacity of 48 amps, a 2 amp charger will take a whole 24 hours to charge a battery fully.

That is twice as long as a 4 amp charger would take to charge the same battery! As such, 2 amp chargers are usually used as trickle chargers or for maintaining your battery at a constant level of charge over an extended period of time, rather than for quickly charging up a car in an emergency.

In general, 2 amp car battery chargers are best used for keeping a rarely-used car connected to a charger for a long period of time. That is ideal for things like vintage cars that don’t get used very often, ensuring that the battery stays constantly charged, so you don’t go to use it on the day only to discover that the battery is flat!

Using a trickle charger to charge a car battery

Most trickle chargers run at around 2 amps, which isn’t much. As amperage indicates the number of amps transmitted by any charger in a single hour, and most car batteries hold a capacity of 48 amps, a trickle charger will take at least 24 hours to get your battery up and running, and potentially significantly more if the battery is old and in poor condition!

Trickle chargers are generally used simply for maintaining your car battery and making sure that it never runs out of charge completely, which can cause problems and damage the lifespan of the battery significantly. A trickle charger will take a long time to fully charge your battery, as it is not designed for that purpose, but it will automatically switch off when the battery reaches full charge.

Trickle chargers are often used by professional mechanics. They use them to keep car batteries running while the rest of the car is being maintained, ensuring that the battery does not run down during maintenance, and preventing it from being empty when they go to start the car up again.

Charging a dead car battery

One of the most common questions about charging a car battery is, “how long does it take to charge a dead car battery?”. There is no single answer to this question, as it varies depending on the size of your battery and how many amps your charger is running at. In general, though, it is likely to be somewhere between 4 hours and 24 hours, with 1 hour being usually enough to get the car started up again. Most chargers run at 40 amps, but a 40 amp smart charger is likely to be the best bet for recovering a completely dead car battery as fast as possible.

Charging a car battery while driving

It is possible to charge a car battery simply by driving around. That obviously won’t work for a battery that is completely dead, but if you just need to add a bit of charge to a battery that is running a bit low, then driving is helpful.

The usage cycle of a car makes a major difference in battery life. Leaving a car inactive over a long period of time will drain the battery much faster than using the car regularly will do! Similarly, if you accidentally leave your AC or car lights switched on for a long period of time, it will bring the battery further down.

In this situation, leaving your car idling or going for a short drive will push your car’s battery charge levels up a little bit. It won’t charge the battery fully, and you will need a proper charger for that, but it might be able to make a small difference. Similarly, the faster you drive, the faster the car battery will charge. It is also important to remember that any electrical features such as lights, stereo, heater, or AC will all slow down the recharge process significantly.

Car battery charging: top tips

There are a few handy tips you can use when charging a car battery with a 12-volt charger to maximize the efficiency and effectiveness of your car battery charging process. All of the methods mentioned above will charge your car eventually, but some of them are likely to be faster than others.

If your battery is completely flat, you are going to want a jump starter in order to get it up and running as fast as possible. Even a fast 12-volt charger will take a little while to get your battery to a usable level, but a jump starter should be able to get things started in seconds. They are well worth having available as part of your emergency backup kit!

Deciding which car battery charger you need to charge your car battery is an important part of the process. There are many different options available, and using too many amps can overcharge your battery and reduce its lifespan.

Many of the cheaper car battery chargers on the market actually transmit more amps than their packaging claims, which is a major risk. As such, it is worth the added expense of making sure that you buy the high quality and legitimate car battery charger from a legitimate manufacturer.

Conclusion

The world of car battery charging does not have to be a complex and confusing one. The length of time that your car battery will take to charge is simply dependent on how drained it is, the amperage of your charger, and the size of your battery. In general, though, you are looking at several hours to get your battery fully charged.

Hopefully, our guide above has helped to provide you with all of the information you need in order to determine how long it is likely to take to charge your car battery with the equipment you have available. It is worth making sure that equipment is the best it can be, ideally with a 40 amp smart charger for maximum speed and security combined!