how long to leave a car running to charge battery

How Long To Leave A Car Running To Charge Battery

The car battery is one of the key parts of every car. We depend on them to start our vehicle and run other parts that don’t run on fuel power. Unfortunately, as important as the battery is, it’s also one of the most volatile parts of our car. A car battery usually needs to be replaced after about two to three years. However, your car battery can die faster if you don’t charge and maintain it properly. Yes, there are tons of other reasons that can kill your battery, but not charging correctly is a key one. So, it’s essential to have proper knowledge and information about charging. In this article, I’ll be discussing all there is about charging, including when,  how long to leave a car running to charge battery. So without further ado, let’s begin.

How Long To Leave A Car Running To Charge Battery?

After a considerable period of idling, a car battery can take up to 20-30 minutes of driving to store some power in it. However, several factors like the battery and charging condition, how long it was idle, and the temperature plays a crucial role in deciding how long it’ll take to recharge the battery.

How Often And How Long To Run A Vehicle During COVID-19 Pandemic Closures To Keep It Charged And To Run

In this corona pandemic, many of us had our cars sitting in the garage because we didn’t need them as we were working from home. However, cars are meant to be driven regularly. If you keep it idle for an extended time, it can result in a good amount of repair bills afterward. Throughout that idle period, the battery of your car is usually the most affected part.

car maintenance during covid

How often and how long you should drive to keep the battery from dying is a complicated question. Several factors come into play. As the battery and the charging technology have improved so much over the years, automotive industry experts say taking your car for a spin every two weeks for half an hour should do the job. It’ll also keep other moving parts and the tires active.

Charging A Car Battery: 4 Things To Remember

Charging your car battery with right charger regularly is an efficient way of keeping it healthy. However, there are four things you should remember before plugging in the charger.

Charging A Car Battery

Dirt And Corrosion Of Battery: Keeping the battery clean is the easiest yet most effective way of having a long battery lifespan. Dirt and corrosion buildup on the cable and the terminals can hamper the distribution of power output level and decrease the battery efficiency. Additionally, you have to clean it anyway when you charge, so why not do it routinely?

Low Temperature And Excessive Heat: The weather has a significant impact on the battery and its charging performance. Low temperature can reduce the battery’s ability to deliver the full potential power, while excessive heat can reduce the ability to hold the charge by evaporating battery solutions. So, in the cold, try to use a battery heater, and in summer, keep the ambiance cool while charging.

AMP Alternator: It’s not always the alternator’s duty to charge your car battery. Excessive dependency on the amp alternator can be a bad thing, resulting in lousy battery performance. Understand when to depend on an alternator and when to use a dedicated charger.

Car Electronics: Lastly, always remember to turn off every in-car electronics while charging. Power-hungry electronics are one of the key reasons for battery drainage, and using them while charging won’t let the battery charge.

Charging A Car Battery

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What To Do Before Charging A Battery: Some Basic Facts

What To Do Before Charging A Battery

Before charging a battery, there are several things you should do. Let’s have a quick look at them.

  • The first thing to do is wear safety gear. As you’ll be handling electricity, it’s crucial to avoid any accident.
  • Sniff around and see if the battery is leaking any acid or gas. If the battery is hot, let it cool down before charging.
  • Remove the battery if needed. However, most car batteries can be charged without removing them.
  • Car batteries are usually charged by a trickle charger. Before buying the charger, make sure it’s compatible with your battery.
  • If the battery is above 12 volts, you can safely charge it by driving. If it’s under 12V or completely dead, you should go for a dedicated car charger.

Top 3 Things That Can Drain Car Batteries In Winter

In freezing a cold, your dead car battery can be real trouble on a cold winter morning. Your car isn’t responding, the headlights or wipers are now working, and most importantly, your car’s heater isn’t functioning. These things are enough to ruin the day for you. Overall, a drained battery can be pretty frustrating in winter. So let’s look at three key things that can drain car batteries in winter.

Drain Car Batteries In Winter

  1. Freezing cold is the most obvious reason of all. When the electrolytes interact inside the battery, they leave a water discharge that freezes in cold weather. Then, these water turned ice cubes reduce the battery’s capacity. When the engine needs more power to start, the battery drains easily because it doesn’t hold the amount of energy it’s supposed to.
  2. Corrosion at the battery terminal can be another significant reason for battery drain in winter. Corrosion primarily happens when the metal piece of the terminal is exposed to water. What can be a better season than winter to have moisture and water around the battery? You might not be able to prevent rust and corrosion, but you can definitely clean up the corrosion and prevent rapid battery drain.
  3. The last reason is not particularly exclusive for winter. However, it occurs more in winter than in other seasons. Heaters in your car tend to draw a big chunk of the battery. In addition, some cars don’t have the auto turn off the feature for electronics like the headlight, radio, or GPS. If you drive your car regularly, the alternator can handle those power consumption. However, these electronics can squeeze the battery in an idle car and leave it dead.

Car Battery Charging System

As I might already know, based on the previous discussion, there are two basic ways to charge your car battery. Both of them are effective and used in different scenarios. The methods are:

How To Charge A Car Battery Properly

1. Charge Under Alternator Through Driving

An alternator is the most common and convenient way of charging your car battery. Besides, that’s the key focus of this article, too, is how you can charge the battery by driving around. As long as the battery is not entirely dead or below 12V, you can charge it through driving. Again, there is no step-by-step guide; just keep all the car electronics turned off while driving.

2. Charging By A Dedicated Charger

Using a dedicated charger is easy too, but there are some steps to it.

  • First, follow the steps I previously mentioned above before starting the charging process.
  • Then park the car, set it in neutral gear and turn off all the car electronics.
  • Then, before plugging in the charger, remove all the cables. Finally, start from the negative terminal to avoid any short circuit.
  • Now, plug in the charger and try to select the slowest charging speed possible. Fast charging always takes a toll on the battery’s health, so you are better off avoiding it.
  • Clean the terminal and plug the battery in.
  • Leave the battery for charging overnight (preferably at the slowest rate). Then, the following day, try to start your car multiple times. If it starts every time, that’s a general indication of sufficient charge. You can also use a voltmeter too to check the charge accurately.

Car Battery Charger Type

For the better battery charging you have to use proper car battery charger to get the hundred percent output from car battery. You will find the several types of charger in the market but select the proper one as per your car model or car mechanics/manual instructions. Always remember that proper charger gives you proper/exact output. There are 3 types of car charger for your car that we are mentioned below:

  1. Linear Charger
  2. Multi-Stage Charger
  3. Trickle Chargers

Don’t Get Stranded: Here Are Top States For Dead Car Batteries

Previously, I discussed the mishaps a dead battery can cause you. Now, the USA is one of the leading countries in the world in terms of cars per capita. Every year, millions of car owners suffer battery death due to different reasons.

Top States For Dead Car Batteries

Unfortunately, the number is not good, and it’s only increasing due to weather extremes like wildfires and increasing cold every year. Below, the list shows the top ten states in the US based on its battery replacement rate in 2017.

  1. Florida
  2. Louisiana
  3. Arizona
  4. California
  5. Mississippi
  6. Nevada
  7. Texas
  8. Alabama
  9. Oklahoma
  10. Georgia

How To Make Your Car Battery Last Longer: 7 Tips to Extend Your Car Battery Life

Depending on the car, its use, and the battery itself, car batteries usually have a life span between two to five years. Apart from those factors, following the tips I mentioned below can maximize your car’s battery life.

Tips To Extend A Car Battery's Life

  1. Regular Car Driving: Driving your car regularly is the best way to keep the battery running for years. Daily use keeps the battery cell active and keeps the charge holding capacity intact.
  2. Shorter Trips: When you start a car, it draws a hefty chunk of power from the battery. But on shorter trips, the amount of energy spent for the start can’t be recovered. So, it’s best if you don’t drive the car often over a shorter period.
  3. Unnecessary Power Consumptions: While parked or idle, keep all sorts of electronics turned off. Many of us keep the AC or radio turned on, and over time, these unnecessary power consumptions can wear out the battery.
  4. Prevent Corrosion Buildup: Cleaning your battery and the cables can really help with a balance and uninterrupted power distribution. So, keep the battery and cables clean and prevent corrosion buildup.
  5. Insulate The Battery: Sudden weather changes can be harmful to the battery. The best way to prevent that is to insulate the battery. In extreme heat or cold, the insulation will help maintain a moderate temperature.
  6. Monitor Your Battery: Keep a tab on the battery condition regularly. It’ll help you understand if you are doing anything wrong and maximize the battery’s life expectancy.
  7. Good Battery And Charger: Lastly, invest in a good battery and charger. A battery or charger is not something you replace every day. So, buy a good one for years of uninterrupted service.

Car Battery Facts: Some Comprehensive Answer!

Battery maintenance and health is the most crucial things for every automatic vehicle. We added some important car battery facts here. You can find it out from here and use it to your daily life to prevent car battery damage. You can also check this article on 6 Surprising battery facts to know more about it.

How to check a car battery

How Often Do I Need To Use My Car To Prevent Battery Death?

The answer to this question, again, depends on lots of variables. In addition, automotive service experts, technicians, and on forums people tend to have different opinions about this topic. The batter and alternator technology have improved a lot over the years. As a car enthusiastic myself, I think driving your car once in a week should easily hold off the battery death.

How To Charge Car Battery While Parked?

How To Charge Car Battery While Parked

As you might already know, your car battery gets the charge in two different ways. One of them involves driving around. The other one is using a trickle charger to charge the battery. So if you want to know what’s the best option to charge the battery while parked, then a trickle charger is your best, safest, and most efficient bet.

How To Maintain Your Sitting Car Battery?

How To Recognize If Your Battery Is Being Charged

Driving is the most reliable way to maintain your sitting car battery. Just take it for a spin sometimes, so the cells remain active. Besides, when you are parking your car, and you know you won’t be driving for a while, make sure you turn off every single car’s electronics. Battery insulation can also help maintain battery health in harsh weather conditions.

Frequently Asked Questions (FAQ)

car battery faqs

Q1. How Long Do I Need To Run My Car To Charge The Battery?

A) As the answer depends on different factors, anyone can only speculate how long you need to run your car to charge the battery. Depending on what car you drive and how much power your electronics draw, running the engine for 10-20 minutes can recharge the amount your starter took.

Q2. Is It Safe To Leave A Car Battery Charger On Overnight?

A) Like smartphones, many of us prefer to put the car battery on charge at night when we don't need it. As long as you can set the charging rate and set the lowest speed, charging overnight won't be an issue at all.

Q3. How To Recognize If Your Battery Is Being Charged?

A) Primarily, if the car starts, that's a good indication that your battery has charged. However, to measure it accurately, you'll need a multimeter. Start by taking the terminal caps of the battery. Then clean the terminal and attach the positive terminal and negative terminal of the battery and multimeter. If the reading shows 12.4V or above, that means your battery is charged. Anything lower, then you should charge it again sometime.

Q4. How Long Should I Idle My Car To Charge The Battery?

A) Idling the car is another good way to recharge the battery without driving the car. However, it takes more time compared to charging through driving. Ideally, 10-15 minutes of idling shul be enough to generate a bit of power for at least one start.

Q5. Does Revving The Engine Charge The Battery?

A) If you know what revving is and how an alternator works, you might already have the answer. Engine revving not only charges the battery but makes the alternator charge faster. When you rev the engine, the crankshaft moves faster; therefore, the belt turning the alternator runs faster. This way, the alternator can generate more power quickly, charging the battery faster than usual.

Q6. Does Idling Drain Your Car Battery?

A) Yes, idling your car drains the battery over time. When the car is idle, the alternator still works to deliver some charge to the battery. But at the same time, if you decide to use power-hungry car electronics, the alternator won't be able to keep up with the demand. Eventually, the battery will drain.

Q7. What Happens If Your Car Idles For Too Long?

A) Idling your car can charge the battery slowly. However, there are other things to consider which can affect your car health in the wrong way. First, the fuel cost adds up, and the pollution is the same as a moving car. Then, idling a car for too long can be stressful for the engine too. Apart from charging purpose, traffic, or signal, idling is somewhat unnecessary.

Q8. Will My Car Battery Die if I Don't Drive My Car?

A) If you don't drive your car, sooner or later, it'll die. How long it'll take to die depends on the car electronics. Modern-day cars have in-built computers that monitor the car system constantly. This system draws a considerable amount of power and eventually leaves the battery for death. Depending on the car and its off-time energy consumption, it can take two to six weeks before the battery dies.

To Wrap It All Up

Battery and the alternator is the most crucial part of a car after the engine. If you don’t maintain the battery properly, you’ll end up with a malfunctioning car eventually. Now that you have read my article, hopefully, you can better understand how a car battery functions and how long to leave a car running to charge battery.

As you have seen, there are quite a few ways of charging the car battery. If you memorize the instruction I provided and follow them carefully, you’ll never face a battery death in your lifetime.

About the author

Michael is the lead content creator for As a car enthusiast and based on his real life experiences he is sharing his opinion about various automotive vehicles and parts. So you can get the best experience! Happy reading.

About The Author

Michael H. Smith

Michael H. Smith

Michael is the lead content creator for As a car enthusiast and based on his real life experiences he is sharing his opinion about various automotive vehicles and parts. So that our reader, can focus solely on buying best gadgets for their automobile and get the best products reviews and guide experience!

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