How Long Can a Car Battery Sit Unused?

Reviewed by

Richard McCuistian, ASE Certified Master Automobile Technician

Technical Reviewer at CarParts.com

Written by CarParts.com Research Team - Updated on February 26th, 2024

Reading Time: 4 minutes
Summary
  • Generally, you can safely let the car battery sit for less than three weeks.
  • Connect the battery to a trickle charger if there’s a power outlet nearby.
  • If you plan to put the car battery in deep storage, disconnect it from your vehicle.
  • Before putting the battery in deep storage, charge it completely, keep it in a cool and dry location, and put it on a battery maintainer.

So how long can a car battery sit unused?

Well, it depends on whether or not the battery is in a vehicle. A battery that isn’t in a vehicle will hold its charge a lot longer than if that same battery is in a newer vehicle with a lot of electronics.

Storing Your Vehicle

While planning on storing your vehicle, one of the first things you must consider is how long you can leave your battery unused. There is no exact answer that applies to all vehicles, but it should be okay to let your battery sit for less than three weeks.

WCar batteries usually last for about three to four years—but leaving your car sitting for far too long hastens the decay.

Note that this rule of thumb isn’t universal. Some vehicles require one of the fuses to be removed for extended storage. Chryslers from the mid-1990s through the 2000s referred to this as the “ignition off draw” fuse (IOD). It’s well marked in the instrument panel or underhood fuse box. Some vehicles will have the IOD fuse(s) in a plastic cage so you can simply pull the cage to disengage the fuses and push it back to re-engage the fuses. 

Others simply have the fuse marked and a place to put it in the panel while the vehicle is being stored. The IOD fuse typically disables accessories like the radio, along with the power seats, mirrors, and windows.

Pro Tips are nuggets of information direct from ASE-certified automobile technicians working with CarParts.com, which may include unique, personal insights based on their years of experience working in the automotive industry. These can help you make more informed decisions about your car.

Pro Tip: There are numerous modules that receive a whisper of voltage that, left long enough, will drain the battery.

Most modern vehicles require power even while parked and their engine is off.

Your alarm system, electronic control settings, and evaporative emissions system will continue to draw battery power. Your vehicle may not start if you leave it parked for months with the battery connected.

If you have access to a power outlet, you can connect your battery to a trickle charger which will keep it topped up and prevent it from being drained completely.

But if you plan on storing your vehicle long-term and it doesn’t have an IOD fuse (check your owner’s manual to be sure), it’s better to disconnect the battery. This will preserve the battery’s charge, allowing your vehicle to start right back up once it’s reconnected.

Just keep in mind that you may need to reprogram things like your radio presets and seat memory buttons. It’s also important to drive your vehicle for a while before your next emissions test in order for the system to get a passing result.

How to Store a Car Battery

If you intend to keep your vehicle in long-term storage, you’ll need to make sure to do the following:

  • Give it a full charge prior to storage
  • Store it in a cool and dry location
  • Put the battery on a battery maintainer

After taking your battery out of storage, inspecting the case for any signs of damage or leakage is important. Check the battery cable terminals for any corrosion that could cause poor contact and prevent proper charging and current flow. You should also look for the date of manufacture and consider it when deciding whether a battery replacement is necessary. With age, the battery’s capacity may be reduced which can cause slower-than-normal engine cranking.

Where to Find a Car Battery Replacement

If you don’t have a battery stored, and you find yourself in need of one, you can check out our extensive selection here at CarParts.com.

We offer high-quality car batteries sourced from reputable brands in the industry. Whether you drive a compact car, SUV, truck, or any other vehicle type, we have the perfect car battery for your ride.

To start, simply visit our website and use our vehicle selector to view compatible batteries. Then, use the search filters to find the ones that match your preferred brand, price, type, and series. Our catalog includes accurate and detailed fitment information, so you’re sure to get exactly what your car needs to get back on the road.

Our distribution centers are strategically located across the country, so expect your orders in as fast as a few days. Take a look at our selection now and order today!

About The Authors
Reviewed By Richard McCuistian, ASE Certified Master Automobile Technician

Technical Reviewer at CarParts.com

Richard McCuistian has worked for nearly 50 years in the automotive field as a professional technician, an instructor, and a freelance automotive writer for Motor Age, ACtion magazine, Power Stroke Registry, and others. Richard is ASE certified for more than 30 years in 10 categories, including L1 Advanced Engine Performance and Light Vehicle Diesel.

Reviewed By William Guzenski, ASE Certified Master Automobile Technician

Contact Center Manager and Technical Reviewer at CarParts.com

William “Bill” Guzenski has produced hundreds of how-to videos for the automotive community. He's an ASE Certified Master Automobile Technician, and is affiliated with the Specialty Equipment Market Association (SEMA). He loves attending race events and car shows throughout the country, as well as traveling in his 40-foot motorhome, exploring abandoned mines and ghost towns.

Written By CarParts.com Research Team

Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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Published by
CarParts.com Research Team and William Guzenski, ASE Certified Master Automobile Technician and Richard McCuistian, ASE Certified Master Automobile Technician
Tags: battery