Will Car Battery Die If Not Used?

Many people now use public transportation for their daily commutes and long-distance trips. This means their cars are not getting regular warm-ups. For many people in this category, one of the most nagging questions at the back of their minds is their car battery’s health.

In this article, we take an in-depth look at how long a car battery can stay charged without use. By the time you read this article to the end, you will know everything there is to know about your car battery and its shelf life.

So will a car battery die if not used for a long time? It depends. Your battery can discharge completely after a long time of disuse. But you can recharge it to full capacity. The quality of the battery and its underlying technology will determine whether you can still get some life out of it after a complete discharge. 

How Long Can A Car Battery Last Without Being Used?

A car battery can last a little under two months without use. If you go beyond this, your battery may not have enough amps required to crank your engine over without damaging it.

Car batteries have a natural, internal chemical leakage or self-discharge. And today’s vehicles draw tiny amounts of power from the car battery when not in use. They use the power to keep electrical systems ‘alive.’

But over time, with consistent amounts of power used up by the electrical systems in your car, the battery becomes fully discharged if you don’t drive the vehicle.

To prevent this situation, you may need to get a maintenance charger to keep your car battery in excellent condition.

How Do You Keep A Car Battery From Dying When Not In Use?

You can keep your car battery from dying when not in use by disconnecting it for storage. This is what you should do if you will travel out of town or taking a break from driving your vehicle for a long time.

The car battery is a vital component and significantly contributes to running your automotive gadgetry. Without it, your automobile is nothing but a big piece of metal, upholstery, and plastic.

Here’s how to store your car battery:

  • Get and wear a pair of gloves, then disconnect the cables. Start with the black (negative) cable and then move over to the red (positive) cable.
  • Don’t let the negative and positive cables touch each other for any reason. The result could be disastrous.
  • Get Ziploc bags and tie them around the end of the cables to keep moisture out.
  • Examine the car battery for signs of damage or leakage from the case. Use a pair of goggles when taking this step.
  • Get rid of any signs of corrosion with water and baking soda. Clean the top of the car battery and the terminals to remove dry electrolyte.
  • Check the level of electrolyte left in each cell of the battery, i.e. if the car battery has filler caps.
  • If any cells are low, fill it up to the recommended level using distilled, de-mineralized or de-ionized water. Do not overfill them for any reason.
  • Charge the car battery if necessary. Recheck the electrolyte levels after the car battery cools down after recharging.
  • Remove the car battery from your vehicle and store it in a dry location where the temperature is not so low that the electrolyte freezes.
  • If you can get a float charger or smart charger–which depends on the car battery you use. Connect it to the car battery to maintain its charge during storage. You can always check the manual to determine the charger suitable for the battery. Or you may consult an auto professional for more information.

Should You Disconnect Car Battery When Not In Use?

There are two different schools of thought concerning this matter. The first claim that when you disconnect your car battery, it will help the battery retain its charge for a long period.

ALSO READ: Which Car Battery is the Best for Cold Weather?

However, another set of drivers believe that disconnecting your battery just because you are going on a long trip is more of a hindrance than a help. They claim that most cars nowadays will lose some basic settings such as the trip computer memory, the clock, radio stations, and so on.

Moreover, some cars may even prevent you from entering if the battery is too low, though this is a safety precaution.

So what should you do?

The first thing that you should do before deciding whether to disconnect your car battery is to check your owner’s manual.

If your vehicle comes with some advanced features or security system, you may need the help of a professional to reset the system when you reconnect your car battery.

The effort to reset your car’s electronics and accessories may far outweigh the benefits of draining your battery. If that is the case with your vehicle, consider other alternatives such as the use of a battery tender.

Can a Dead Battery Be Recharged?

Yes, a dead battery can be recharged. If you discover that your car battery is dead after turning your key in the ignition and nothing happens, the first thing you should do is to determine how dead the battery is before you even recharge it.

A healthy battery will show 12.4-12.7 volts across the two terminals when you measure with a voltmeter. A voltmeter is a readily accessible device for diagnosing car battery issues.

If, however, the voltmeter shows a reading that is lower than 12.4 volts, you will likely run into problems when you try to start your car.

Now, how much lower the voltmeter reading is will significantly determine the method you should use to charge the battery after you have jump-started your car.

This is what you should do if the voltmeter shows a reading above 12 volts:

  • You should go for a drive, using as little electricity as possible, i.e. no lights, no stereo system, and all cooling and heating functions switched off. This is to ensure that the alternator sends as much energy as it can muster into the car battery. Higher revolutions pour more power into the charging circuit, so keep your car above idle as much as possible. Aim for nothing less than a thirty-minute drive to boost your battery to a safe level.
  • If your voltmeter shows a reading below 12 volts, you need to get a dedicated battery charger as soon as possible. Although the alternator in your vehicle can charge a good battery, it wasn’t designed to recharge a dead car battery.

It’s not advisable to use your alternator to recharge a dead battery, or you will end up damaging the alternator.

This is because it is forced to work overtime not only to fill up the battery but also to supply electricity to other electrical components in your vehicle.

Even the dead battery can also get hurt as using an alternator to recharge it will undercharge it. This will make it less likely for the battery to retain the charge that the alternator puts into it.

How Long Will A Car Battery Last If Disconnected?

Batteries are usually slow to self-discharge. However, the longer they sit without being used or disconnected, the more charge they lose.

This is the issue that devices which are known as “battery tenders” were designed to address, a somewhat minimal float charge to offset the self-discharge.

So, a car battery will keep its charge for up to two months or longer when disconnected. But this will depend on the potency of the car battery and the draw of your car when the time comes for you to start your engine.

Does Idling Car Drain Battery?

Idling a car will not drain or kill your battery unless the battery has a problem such as an inability to hold a charge. Another common problem is if your vehicle is has several power-sapping electrical accessories.

As long as your car engine is running, even if it’s doing nothing more than idling, the alternator will continue to charge your car battery. However, this charging may be somewhat slower compared to when you are driving.

When you drive along the highway, your car’s alternator will operate at a much higher rate per minute. This also enables your car battery to recharge at a faster rate.

ALSO READ: Which Car Batteries are the Best?

The car battery will eventually become fully charged since it receives a substantial charge for an extended period. Idling your car will not charge your battery that fast or more fully, but at least it is still being charged.

Alternators charge car batteries even when the vehicle is not moving because they are linked to the engine, not the wheels. So, as long as your car engine is running, the alternator generates and supplies a steady 14 volts. This is because it is the car engine that spins the alternator.

If your car has plenty of high-powered electrical accessories or devices, the alternator in your vehicle may not support all the power demands. The battery supplies the additional power required to keep the dynamic electrical accessories running, which can drain it.

Will Car Battery Die If Not Used
Image: Flickr.com

What Is the Allowable Time to Idle Your Car?

Auto experts recommend idling your car for at least 30 seconds to a minute. It won’t harm your car battery, the engine, and the environment if you limit idling to that time-frame.

However, too much idling can have an unfavorable effect on your car’s engine. And that is because the fuel in your vehicle is not entirely burned as the car idles below its maximum operating temperature.

This leads to an accumulation of fuel residue on the walls of the cylinder. Fuel residues can also debase the engine oil, reducing its lubricating ability.

So idle the engine for 30 seconds and then drive. If the car and its components are not sufficiently warmed up when idling the engine, driving will charge them up faster.


The more you use a car battery, the faster it loses its charge. The type of car battery you use and your geographical location will determine how long your battery will last if left unused or disconnected.

Most of the batteries used in today’s cars are tough enough to start your vehicle’s engine, even if left unused for two months or more. However, check your owner’s manual or talk to an auto professional before you disconnect your car battery.