How Long Does it Take to Recharge a Car Battery?

A common misconception is that a flat battery needs to be replaced. And while this may be true it is also possible that you just left your lights on and that it has been completely depleted. If you have a battery charger you can actually recharge a battery.

In this article we will look at how long it takes to recharge a car battery and what you have to do when you get a flat battery. It can be a real annoyance to get a flat battery but hopefully we can help you deal with this and get you back driving as quickly as possible.

How Long Does It Take to Charge a Dead Car Battery?

If you are using a 20 Amp battery charger on a normal-sized car battery you can expect it to take roughly 2 – 4 hours on average to receive a full recharge. Using a weaker 4 Amp charger this process could take between 12 – 24 hours but it can vary depending on the size and type of battery you have.

The important thing to remember is that as long as your battery can still hold a charge and there are no other issues with your car you do not need a full recharge. After an hour you should have enough charge to start the car and from there. The natural running of the engine will recharge the battery the rest of the way.

When it comes to charging speed in general the higher ampere output from your charger the faster it will charge the battery. You may wonder why anyone would have a low amperage charger then. Simply put it is better for your battery's health to recharge it slowly.

Charging Times With Different Charger Strengths

As you can tell from the above chart, the stronger the amperes supplied by the charger the faster the battery will charge. A 40 amp charger will get you on the road much quicker but as we have mentioned this rapid charging is not great for the battery.

What Is the Best Speed to Charge Your Battery?

Ideally your battery is charged by driving your car but if you accidentally leave on a light in the vehicle or you have not used it a long time the battery can become completely drained. If you simply have to recharge the battery because it is dead then you should if you can do it in the best way to protect the battery. Like good BBQ you will want to go low and slow with your recharge.

You can use a powerful 40 amp charger and have a full battery within an hour but the cost may be that it causes damage to the battery. Ideally you want a battery charger that gives out 2 – 4 amperes or has an adjustable amperage.

A lower powered battery charger mimics the natural charging rate that the driving of your car provides for the unit. This should help to protect the longevity of your battery and avoid the need for a replacement.

What Can Cause a Flat Battery?

There are a number of reasons why you may wake up to a flat car battery and commonly it could be because you forgot to turn off the lights or some other electrical element of the car did not turn off when you last used the vehicle.

Alternatively, the battery may have reached the end of its life or there may be other electrical systems such as loose wires, a bad alternator, extreme cold or just plain lack of use. As mentioned a flat battery is not always a dead one so recharging is definitely an option unless this highlights that the unit is not holding a charge.

Can You Do a Short Charge and Then Let the Car Finish the Job?

We did mention earlier that in a pinch you can likely start driving after an hour's worth of charge. This is true, technically you can do this but it is not really advised. We also mentioned that the natural charge rate for a car is low amperage and takes a while.

If you are going for a long drive and minimize your electrical system use you may get a decent charge in your battery in this way but you may not get it fully recharged. This is not great for the battery.

Choosing the Right Battery Charger

Ideally when you buy a battery charger you will not have to use it very often. In fact many people may buy a charger when their battery is already dead. Whether you are buying one to use straight away or you are getting one for preventative maintenance do not skimp.

Modern chargers are easy to connect and they have charging monitoring so they can regulate the amps they produce. You will want to make sure the unit has the amperage capabilities you require. As mentioned if you have the patience a low amperage unit is best to protect your car battery's longevity.

The temptation to get a cheap unit will be great but just remember that they can often claim amperage that they can not provide. A quality unit is best and again try to go low amps to protect that battery.

A good brand to opt for are CTEK chargers, they have various sizes of charger to help suit your needs. Whether you go quality or need a budget option you will likely spend between $30 - $100 to get a new car battery charger.

When Do You Know Your Car Battery Needs Changing?

When a battery is damaged or has simply reached the end of its useful life no amount of recharging is going to make it work right. After a while the battery simply can not take a recharge and it is dead. Depending on the quality of your battery it can last between 2 – 6 years on average before it needs to be replaced.

If you have been driving the car regularly for decent periods of time then the battery should remain well charged. If however your vehicle struggles to start this might be a sign that the battery is getting old and not holding its charge anymore.

Many cars today have dashboard warning lights to tell you if you have a battery issue. If this pops up on your dash then you either have a dying battery or some other related charging issue that needs to be looked at.

Conclusion

Depending on your battery charger you may get a full recharge in anywhere from an hour to 2 days. This all depends on the amperage supplied by the charger with high amps charging the battery much faster. Quicker charging however can damage the battery so if you have time use a lower 2 -4 amp battery charger.

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