A dead battery can leave you stranded in an instant, but there are some things you can do to avoid getting caught in that situation. With the proper battery charger, you can have your battery charged enough to crank the vehicle in just a few minutes. Depending on what led to your battery getting discharged in the first place, you might need to consider replacing your battery if it can no longer hold a good charge. Here’s how long you can expect it to take to get your car back up and running again.

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How Long Does It Take To Fully Charge A Car Battery?

Right now you’re probably wondering how to charge a car battery and how long it’s going to take. Recharging your battery does take a little time, but the specific amount required depends on a few things. First, just how dead is that battery? If it’s been totally discharged, then it’s going to take longer to recharge it than if it’s still at half charge. Also, the type of charger that you’re using plays a big role in the length of time required. The higher the amperage on your charger, the less time it will take. However, there is a trade off. Charging at high amps can cause damage to the battery if you leave the battery charger on there too long.

Not only do battery chargers come in different amperage, but they are also different types. Linear chargers typically operate at a lower amperage, but they take longer to completely charge your vehicle. Burst chargers utilize higher amperage, but they work in short bursts. This type of charger is generally considered safer on the battery than a linear charger. So, how long will it take to charge your battery? Here are some common amp ratings for chargers and how long you can expect it to take to charge your 12 volt car battery.

  • 40 Amp Charger

This kind of charger will get your battery back up to speed quicker than the others. If your battery is completely dead, you can expect that it will be charged enough to crank your vehicle in 20-30 minutes. Charging at this fast of a rate will generate a lot of heat, and you should never charge your battery with a charger this powerful for more than about 30 minutes.

Once you’re able to start the car, you can let the car’s alternator continue charging the battery until it’s full. While the car engine runs, the alternator spins and provides a charge through the vehicle’s charging system to charge the battery. Another option is to switch over to a charger that has a lower output to continue charging until it’s full.

  • 10 Amp Charger

A 10 amp charger will take a little longer to charge your battery, but you can safely leave this charger on there longer without damaging your battery. This charger will take anywhere from 2-4 hours to charge your battery high enough to start your vehicle. A battery that is around a 50% charge is generally powerful enough to start the car. To reach a full charge, it could take 7-8 hours on a 10 amp charger. However, you should not leave this charger on your battery for more than 8 hours or you could risk overcharging and damage the battery. Too much car battery charging is not good!

  • 2 Amp Charger

This is a common type of car battery charger that outputs 2 amperes of power. These chargers work much more slowly than ones with higher amperage, but they can also be left on your battery for longer periods of time. To get your battery charged enough to crank your car, you’ll need about 4-8 hours on a charger of this kind. To reach full capacity, a 2 amp charger may need to be left on overnight or even up to 24 hours.

  • Trickle Charger

An automotive trickle charger is not really intended to charge a dead car battery. This type of charger typically outputs extremely low amperage in the 0.5 to 1 amp range. This kind of charger is meant to be connected to your car’s battery when it is not in use. It helps keep the battery from draining when the car is not being used by providing a slow trickle charge. Typically, these chargers are used by people who have a second vehicle that they do not drive much or one that sits for extended periods of time.

If you’re a little more mathematically inclined and have some mechanical know-how, you can figure out exactly how long you should charge your battery. You can use the reserve capacity of your battery to determine how many amp-hours need to be replaced in the battery. Then, get a voltmeter and measure how much voltage is left in the battery before you begin charging. If you get a reading at 12.4 volts, this means the battery is about half charged and needs half the car battery amps replaced. This means there are about half the amp-hours remaining in the battery, so you’ll use your charger’s amp rating to get the time requirement. For instance, replacing 36 amp hours using a 10 amp charger will require about 3 1/2 hours.


What Kind Of Car Battery Charger Should I Use?

In addition to operating at different amperages, there are also different types of battery chargers. The type of battery charger that you use depends on how quickly you need to charge your battery. You want to be careful not to overcharge your battery as that can completely destroy it or at least shorten the lifespan. Here are a few different types of chargers along with their description and preferred uses.

  • Linear Chargers

These chargers are one of the easiest to use because they simply plug into the wall. You connect the terminals to your battery terminals, and let the charger do the work. These chargers usually operate at lower amperages and take a long period of time to fully charge a dead battery. You can buy linear chargers that operate anywhere from 2 to 10 amps. You can use these chargers on any AGM or lead-acid battery, but they’re not always the best choice. The positive to this kind of charger is that they are cheap, and you can purchase one for about $30-$40.

  • Multi-Stage or Smart Chargers

As the name implies, these chargers are a little smarter than the traditional linear charger. Instead of providing a simple charge at the same rate, these chargers can provide higher amps initially to quickly bring the battery, and then they decrease their amperage as the battery charge increases. These types of chargers are the best choice as they are safer on your battery. They start out as a fast charging device, and then decrease their charging rate over time. These chargers are more expensive as they are in the $100 range, but they are much safer and will help prevent the need for a new battery as quickly.

  • Trickle Charger

This type of charger is not intended to recharge a car battery when it’s dead, but these are used when you have a battery that sits idle for long periods of time. With the car just sitting and not running, the battery will discharge over time. The trickle charge provides an extremely low power in the 1-2 amp range. If you are attempting to charge a dead battery, it might take a couple of days with a trickle charger if you are able to get it fully charged at all. These chargers are best to use on a car that sits for extended periods of time between uses.


Tips For Extending Your Car Battery’s Life

There are some things that you can do to help extend the life of your battery. First, make sure that it does not become fully discharged. If you do not use your car frequently, then consider getting a trickle charger that will help keep a charge in the battery. Next, check for corrosion on your battery terminals. Corrosion can harm a battery, and it can also prevent your battery cables from making a good connection and cranking the car properly.

Next, try and avoid running a lot of devices on your car’s electrical system, especially while the car is idling. This takes a huge toll on your battery, and can cause one to die earlier than it should. Short trips are also hard on a battery. If you crank your car and then cut it off again before the alternator can recharge the battery, then the battery begins to get weaker and weaker over time. Cold weather will also affect your battery, so keeping it charged during cold weather is very important!


Charging/Replacing My Car Battery Is Too Expensive. Is There A Cheaper Alternative?

Yes, there is! In fact, there is an alternative that will pay you for your car instead of you having to spend money on a new battery. You could sell that car to Auto Wranglers and get paid cash for it! You can sell us an old junk car or one that’s almost new – we don’t mind either way! We’ll make you a cash offer in about 90 seconds, and the whole process only takes a day or two.

We buy cars everywhere across the nation, so we’ll come to your location just about anywhere. We always provide free pickup and towing, so you never have to worry about paying any hidden fees. If you can’t afford a new battery, then you can sell us your car and use that money to put yourself in a new ride. Go ahead and get your free, no obligation quote today!


How Do I Jump Start My Car?

If your car won’t start and you need to get it running quickly, you can always jump it off if it’s just a dead battery. If you’re wondering how long it takes to jump a car, it’s a quick process! You’ll just need a set of jumper cables and another vehicle that is running with a good battery. Jump starting a car isn’t difficult, but you need to make sure you do it properly to avoid damage to your car’s electrical system.

Start by connecting the positive terminal of the dead battery to the positive terminal of the good battery. Next, connect the negative terminal of the dead battery and ground the other end of the negative jumper cable. Crank the vehicle with the good battery and then attempt to crank the vehicle with the dead battery. It should fire up, and then you can disconnect the cables in reverse order.



A dead battery can stop you in your tracks, but it doesn’t have to be a dreadful event. With a little help from a battery charger, you should be up and running in no time. If, however, you find that your battery has completely died and needs replacing, you’re looking at a larger expense. If you don’t have the money for that new battery, then just go ahead and think about selling that car of yours to Auto Wranglers. We’ll make you an instant cash offer in under two minutes, and we always provide free towing and pickup. Our process is hassle free, so give us a call today to get started.

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What causes a battery to go flat?

Leaving electronic devices running while the car is turned off will drain a battery. Cold weather also causes a battery to become weaker. Short trips where the battery is not able to fully recharge in between can eventually kill a battery. You should ideally let your car get up to highway speeds for several minutes so that the charging system can charge the battery back up to full capacity. Otherwise, the battery continues to drain each time you crank the vehicle, eventually getting so low that the car will no longer crank. On the plus side, a dead battery can reset a check engine light if you have one on!

How long does a car have to run to charge a dead battery?

Your car’s alternator is not designed to charge a dead battery. However, if the battery is not completely dead, you can charge your battery back up by driving the car. You should let the car idle for 15-30 minutes after jump starting the car. If your battery is totally dead or damaged, be aware that you could do damage to your alternator by letting the car run this long with a bad battery.

Is it better to charge the battery or jump start the car?

There is no right or wrong answer to this question. It really depends on how quickly you need the car to be started. If you need to crank the car right away, then go ahead and jump start it. If you’ve got a little time, then charging the battery is the better solution. This will put the battery back to its normal capacity and prevent you from being left stranded again. Remember that cranking a car with a bad battery by jump starting it could damage the alternator if it runs too long.

What is the best car battery charger?

The best car battery charger is a newer, smart charger. These types of chargers give your battery a quick initial charge, but then reduce their power to prevent damage to the battery. These are a little more expensive, but they are worth it to protect your car’s battery. A new battery can easily run $200 or more, so it’s worth investing in a good charger to prevent damaging an expensive battery.