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How Long Can A Car Battery Sit Unused? The Answer Is Here

How Long Can A Car Battery Sit Unused? The Answer Is Here

Owning a car is becoming a general thing right now and the number of cars getting sold out every day justifies this claim.

Yet, there may arise situations where the car may remain unused for weeks, months, or even years. There are several reasons behind the above. To list a few, here are them.

  • You’re using more public transport for day-to-day commutation.
  • You have left your country and the car is still in your garage.
  • You’ve suffered a serious injury that left you bedridden.

And so on. Be it any reason, leaving a car unused for a long time is harmful to both the battery and engine.

This is because by doing so, the battery gets cold and you will find it hard to start the car again. Hence, it’s always suggested to avoid leaving the car used for even weeks.

Still, there are unavoidable circumstances where you couldn’t drive your car. But in such situations too, it’s a suggestion to ignite the engine and idle the car for a few minutes.

This way, you will not witness a dead battery or a damaged engine even if the car remains unused for months. Continue reading to get some more insight into this topic.

How long can a car battery sit unused?

Depending upon the state of the car battery i.e. old or new, its usage, and several other mechanical factors, a standard car battery that’s moderately old and less used can sit unused for a month or two.

That is, even if you don’t ignite the car for a month or two, there are small chances of the battery going cold and of no use.

However, car experts believe that no car should sit unused for such a long time under any circumstances for the sake of the car’s overall health.

Also, remember that a decade-old battery that powers more than the standard number of car elements, may hardly sit beyond a few weeks.


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How long can a new car battery sit unused?

Surprisingly, a new car battery can last for only a week or two if left to sit idle. This is against the used batteries that you can use without any professional assistance after a month or two.

You may find this strange but here’s why it is so. Being a machine, you can expand the life of batteries by using them continuously and not by making them sit for periods.

So, if you feel you can use a battery for a longer period by using it less, you are wrong. In fact, the more the battery will run, the better it is.

That’s the main reason why batteries of heavy vehicles like trucks and buses tend to last for longer than those of smaller vehicles like cars.

Can a car battery go dead from sitting?

Yes, a car battery can go dead from sitting. To understand this in a better way, here’s a quick summary of how a car battery works.

Your car battery produces electricity through an electrochemical reaction. Without going into the complicated chemistry, this reaction involves the movement of electrons from the lead oxide end (anode) to the metallic lead end (cathode).

Since these electrons need a medium to travel from anode to cathode, the medium most batteries use is sulfuric acid. Now, here’s a catch.

As long as the above reaction is taking place i.e. the battery is running and getting charged, the battery will remain in a perfect state.

However, if left to sit unused for long, the reaction won’t take place or you can say that the battery isn’t charging or losing its leftover charge. In a nutshell, the battery will die soon after losing all its charge.

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How do you Keep The Battery From Getting Cold?

How do you keep the battery from getting cold is another common question in the mind of owners whose car sits unused in the garage for months or years. So, below are some ways to keep the battery from getting cold.

Drive the car once a week to keep it charged.

A sitting battery gets cold or dies as it loses its charge at a brisk rate. To avoid this, you can either idle the car (although not a good option) or drive the car for a few miles/minutes.

However, keep in the mind the state of the battery, its size, and the weather outside. Doing the above not only benefits the battery but also lubricates the other parts of your car.

Get yourself a portable battery charger.

Even if you can’t go out for a quick drive, it’s a must to charge a battery that’s dying due to sitting idle in the garage.

To avoid this, you can use a portable car battery charger to charge the battery anytime you feel to do so. You can also use a trickle charger for the same purpose.

Simply insert the trickle charger into the wall socket and connect to the battery terminals.

Choose an ideal parking spot.

If you know that the car is going to sit for a long time, why not park it in an ideal spot? Avoid spaces with any moisture retaining surface like grass as it will initiate corrosion in the undercarriage.

Besides, too much moisture can likewise suck out power from the battery if parked for long. Hence, choose a solid surface like a gravel-based pavement.

Store the battery in a dry and humid place.

If you are not using the battery, it will get cold. And as the battery discharges quickly in colder climates, don’t leave the battery in the car for long.

Instead, you can detach the battery and store it somewhere else, like in a dry and humid condition.

So, these are some ways of preventing the battery from getting cold.

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How Long Can a Car Battery Stay Charged After Removal?

As said above, a car sitting idle in the car can last for around 8 weeks i.e. two weeks if the battery is moderately old and used.

However, if you plan to detach it from the car and store it in a dry and humid atmosphere, the battery can stay charged for another three to four weeks.

That’s, a battery can stay charged for around 10-12 weeks after removal. However, post this period, you’ll have to charge it.

How do you keep a car battery from dying when not in use?

You can keep a car battery from dying when not in use. For this, consider the following strategies.

  • Keep driving your car for short distances once a week. This not only benefits the battery but also lubricates the other parts of your car.
  • Use a portable charger or trickle charger to charge the battery anytime you feel to do so when driving outside is not feasible.
  • Separate the battery from the car and store it in a safer and dry place. This is because by doing so, the battery can stay charged for eight to ten weeks.
  • Or you can disconnect the negative (black) terminals and reconnect when you are ready to go.

These are some common and time-effective ways of maintaining a battery sitting idle for long.

How to Store a Car Battery safely when not in use?

If you want to store the battery safely when not in use, here are some cool ways of doing so.

  • Disconnect the battery from the car.
  • Disconnect the battery’s black terminals first and then the red terminal & then store.
  • Store the battery at room temperature. The temperature of the surroundings should not be too high nor too low.
  • Keep charging the battery frequently to maintain sufficient charge in the battery if the need to use the battery arises.
  • Clean the battery terminals with baking soda or another good-quality chemical to prevent corrosion.


Your car battery will lose its charge when left to sit idle for months or weeks.

Though a moderately old battery can sit for 2-3 months without charge, you can enhance the battery storage capacity of the battery by storing it separately.

Plus, charging the battery frequently with a portable charger is never a bad idea.

At last, remember that your car battery is a machine that should keep running. Hence, try to keep the car running for a few minutes if not for long.