How Long To Leave A Car Running To Charge Battery?

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Do you have a car that needs to be charged?

You may not know this, but it’s actually possible to charge your battery by leaving the engine running. If you’re in a hurry and need to get somewhere fast, or if you want to save on gas money, this is an option for you.

So, how long to leave a car running to charge battery? A car can be charged by riding in it for 30 minutes. It takes 30 minutes to charge the battery. But this is not enough time to fully charge the battery. There are other things that you need to think about while driving, like stopping and getting gas or charging your phone while driving.

We all know how frustrating it is when your car battery dies. There are many different opinions about how to charge a car battery, but one of the most popular strategies is to start the engine and leave it running for 30 minutes. But how long should you actually run an engine to charge a car’s battery? Well, there really isn’t a hard answer. It can be anywhere from 10-30 minutes depending on how much power the vehicle needs to recharge its system.

Let’s dig into it…

How Long To Leave A Car Running To Charge Battery?

You may be wondering how long you need to run your car to charge the battery. The answer is that it depends on a few factors. There are many variables, such as engine size and battery type, which can affect how quickly the battery charges while driving or idling. In this blog post, we will explore some of those factors and give you recommendations about whether or not to idle your vehicle when charging your battery.

How long does it take to charge a car battery while driving?

When your car battery needs to be recharged, you can do it by driving the car. But make sure you don’t drive for reasons besides essential goods. If you need to drive short distances for these, this might not be enough to get a full charge so you should check how long it takes to charge your battery before driving again.

To charge a car battery, people usually have to drive for a long time. They should drive for at least 30 minutes. This is not saying that driving your car for 30 minutes will make it fully charged. There are other things to think about too.

Your car can have more than just a clock and radio. Cars have infotainment systems, sensors, alarms, and lots of electrical equipment. Even when your car is off it can use power from the battery to do things like turn on the radio or play music.

Moreover, if you are not going to use your car for a while, you should get a Battery Tender. The battery needs electricity to stay charged. You attach it by putting its claws on the battery’s two terminals. It then plugs into an outlet and it will give electricity to the car so that the battery stays charged when the car is not being used.

How long should you idle a car to charge the battery?

Basically, it takes about 2 hours to charge a battery in idle condition. You need an alternator that can produce 80 amps of power and you also need 14 volts going into the battery. It would take about 2 hours, as long as you can keep up with those requirements for this whole time.

Some people say that if you idle your car for 15-20 minutes it will charge the battery. But this is probably not a good idea. Idling an older car for 15-20 minutes may give it enough of a charge to work, but try not to do this too often or too long.

Modern cars are often designed with what is called a battery management system. This is to help the battery last longer. But this can make it hard for your car to charge at lower speeds. Unless you are moving faster, the battery might not be getting charged very much.

When the engine is on, it can contaminate the oil in your car. This will make the oil less able to protect your engine. Cars are not made for idling for a long time, so when you do idling, there can be more smoke in the car. The smoke will make it hard for the car’s engine to work well. That means that it might not run well or use gas as good as before.

The exhaust system in a car is not able to get water out of it. This makes the exhaust system decay, and eventually, the car will stop working because the air cannot get through.

This is hard to understand, but the exhaust that comes out of our cars makes it even worse for the environment than normal. You know how when you are driving it isn’t as bad because the air gets cleaner? Well, when you are just sitting there idling your car, not only does it make more exhaust particles which pollute more air; even if you turn off your car and don’t do anything else bad for the environment like eating meat or something – if you idle your car then produce more pollution. So try not to idle too much.

Does a car battery charge while in park?

No, car battery doesn’t charge while in park. Starting a car uses up 100-130 amps, and if you idle for 15 minutes, it will be put back to 3-4 amps. If you are only idling for 15-20 minutes the battery will never get fully charged. The charge is going down each time you start and leave the car running.

A car battery does not charge while in park. When the car battery is operational, power is stored to start the engine and recharge a dead battery. In an idle state or in park, most of the energy is going into a resistor that keeps everything steady at 12 volts for refueling purposes.

The alternator will pull from drive train electricity also regenerated with braking to maintain 12 volts which it delivers to your electrical system–like headlights, tail lights or dashboard indicators—but leaving little leftover voltage available to generate additional amps under normal driving conditions.

Does your alternator charge your car battery at idle?

Yes, a car battery does charge while the engine is idling. As long as the alternator is working, which means that it can turn because of the car engine. The alternator makes AC current, and so it charges your battery when you are not driving.

It’s common for people to think their car needs a boost when it actually doesn’t. With most engine designs, the alternator charges the battery without taking any momentum away from the engine; you can easily verify this by idling up a hill with your headlights on.

As long as your headlight voltage is more than what’s coming out of your battery, then everything’s electrically balanced. The main reason for problems in this area is if there are electrical components hooked-up to the battery that draw more current than you might normally expect (e.g., car audio amp), but otherwise if everything appears normal and no part of the circuit has exceeded its current-draw capacity, then there’s nothing wrong other than a mental block.

How to recognize if your battery is being charged?

To tell if your car battery is charged, it should measure at 12.6 volts or higher when the engine is running. If you don’t have a multimeter to tell you the voltage of your battery, you can do a test of your electrical system by starting the car and turning on the headlights.

Your battery should be above 12.6 volts so that your headlights will come on and stay on until you turn them off. A voltmeter is the most accurate way to determine if your car’s electrical system is charged or not, but if you don’t have access to this meter then these steps will tell you whether or not your battery is charging when the engine is running.

If your headlights are dim but brighten when you rev the engine, then that means that your car battery is being charged. If it does not get brighter when you turn on the lights or if they still do go very bright no matter what, then chances are that your car’s electrical system is not charging at all.

Therefore, your battery is bad and you should be looking into replacing it. A car that is not charging has most likely had its alternator or voltage regulator fail. If your car battery has been draining but all of the electrical system tests are okay, then chances are that your dead cell is causing the problem.

This can happen if you discharged the battery by accidentally leaving your lights on or if you do not drive your car for a week. If your battery just dies and you’re sure that it’s good, then chances are that you have a dead cell and need to replace it.

Does idling drain your battery?

Yes, Idling can drain your car battery. The idling also causes the battery to drain which means it cannot charge and could break soon, too. This will make you have to buy a new one. Idling your car can cause a lot of damage. Idling can affect performance over time. It might not work as well and might even break down.

How Many Miles to Charge a Car Battery?

Experts said that you should drive about 7-10 miles to charge the battery of your car. This is when you are driving, not when you are sitting in traffic. When you are sitting in traffic, it is best to turn off your car and wait until you can drive normally.

Assuming that you’re taking pessimistic values, you might suppose that starting the car draws 400 Amps for 15 seconds.

Charge = Current * Time

= 400 *15

=1600 Coulombs

Finally, if the alternator can supply 10 amps more than is required to power the vehicle’s systems while it’s in motion,

Time = Charge / Current

= 1600 / 10

= 160 seconds

So, to be pessimistic again, you should be near to restoring the charge after 10 minutes or so. Of course, the figures may differ for your automobile, but I don’t believe they are that far out.

How long will a car battery last without being charged?

A new car battery can last two weeks without recharging from a generator. But if you don’t charge it for 2-3 months, it will go dead and you won’t be able to start the engine.

The life of a car battery without being charged is not that long, because the moment you turn off the engine a battery stops receiving a charge. And then after a few weeks or months, it will completely lose its charge capacity. If you want to maximize your car’s battery life, make sure to always make use of an alternator charger.

This is why you should always use a trickle charger if your car battery dies and you need to keep it alive for a little bit longer before getting it to an auto shop for further diagnosis. A trickle charger will help the battery maintain its charge without letting its power die out completely, thus giving you enough time to get your car back on track.

With this in mind, it is important to have a trickle charger around. Not only do they help prolong the life of your battery but also protect your car from being damaged or even dying out while you are away at work for hours on end. If you want to get the most out of your car’s battery, use an alternator charger, or better yet, use a trickle charger.

How many volts should a car battery lose overnight?

A battery usually loses about 1-2 volts overnight, so a 12-volt car battery that has 10.5 volts on the morning after last night will be 10.3-10.7 volts on average during the day.


If you want to charge your vehicle’s battery, the best thing you can do is leave it running. The more time that goes by with a car running, the better chance of fully charging your battery. While this may seem like common sense, there are some people who turn off their cars after they’ve finished using them and don’t realize that they’re not actually charging the battery at all! So if you have an electric or hybrid car, make sure to keep it on for as long as possible so it will be charged when needed next.

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