How Long Can a Car Sit Before the Battery Dies?

Modern automobiles have evolved immensely over the past few decades. The technology has advanced so much that we are nearing the era of self-driven cars, not to mention the sophisticated features like adaptive cruise control, …

car battery

Modern automobiles have evolved immensely over the past few decades. The technology has advanced so much that we are nearing the era of self-driven cars, not to mention the sophisticated features like adaptive cruise control, radar safety systems, huge infotainment screens, and other Driver Assistance Technology.

Maintenance of a vehicle is usually focused on its mechanical parts, like oil change and filter replacement, but one of the most important components that are essential for the car’s functions is ignored. 

It is the car’s battery, which seems like a small box sitting on one side of the engine bay, but plays so many important roles in the car’s functionality. A battery essentially starts the car with the help of the starter, and power all the electronic components. Be it the headlights, infotainment system, power windows, rearview camera, odometer, climate control, or wiper blades, all these components are somehow driven by your car’s battery. 

Although we usually don’t give much heed to this important part – as it has a long lifespan and the latest dry batteries are maintenance-free. But there are certain ambiguities that we must be careful about, such as how long would the battery last if the car is left to sit? What are the signs of a bad battery? What to do if the car battery dies? Let us answer all these questions in detail so you don’t get into trouble because of your car’s battery. 

How Long Can a Car Sit Before the Battery Dies?

Modern batteries are getting smarter and better with time, thanks to technological advancements and refined raw materials. Today, a modern battery would last up to 4 weeks if the car is left unused. Although the electrolytes, capacitors, and other components are more sophisticated, a car’s battery has to continuously power different systems, even when the car is sitting. 

These systems include a car’s alarm system, smart entry proximity sensors, climate control, remote starter, trunk opener, and other over-the-air connections including A/C remote start/stop. 

So, even when the car is sitting idle in your garage, its battery is getting drained continuously due to these systems. If it’s a newer, healthy battery, it would last 3-4 weeks at max and it is important that you either start your car once a week for a few minutes or take it for a spin around the block, to keep the battery at an optimal charge. 

Signs your car battery is dying

It is possible that one fine day you might not be able to start your car and the odometer goes blank on you. This is the most definite sign of a dead battery, but your car would likely show certain signs if the battery is getting weaker and going to die soon. Look out for these important symptoms in your car to be aware and replace your battery before any inconvenience occurs; 

  1. Engine cranking slowly – it means that the amperage is too low to provide an optimal start and your engine gives a slow crank. 
  2. Clicking sound on turning the key – in this instance, the power is too low to even start the car and it would only give a clicking sound on twisting the key. 
  3. Dim headlights – this is one of the easiest signs to spot as headlights are the most commonly used parts. 
  4. Issue with electrical parts – these include heated and power seats, wiper blades, infotainment screen, and power windows. A dying battery would not be able to power these parts to function optimally. 
  5. Warning light on the odometer – this is a clear indication that something is wrong with the battery, especially its charge. 

What to do if Your Car Battery Dies

There’s a likely chance that you left your headlights or dome light on and it drained the battery overnight. If you are unable to start your car and the battery is dead, these are the following things you could do to get back on road; 

1- Jump start your car – if in a hurry, get a pair of jumper cables and arrange a car with a functional battery. This is the easiest method and would start your car immediately, and you can leave it running for a few minutes before driving away. 

2- Recharge the battery – If not in a hurry, it is ideal to recharge the battery at home via “slow charging”. This method is better than jump-starting and the battery stores the charge for longer via this method. 

3- Replace the battery – if you feel that the battery has gone bad and corroded beyond repair, it is ideal to get a new one and give your car a new lease of life.  

Related posts: Car Battery Dies While Alternator Is Functioning Well? 

Frequently Asked Questions (FAQs)

1- What can drain a car battery when the car is off? 

Following components/features can drain your car’s battery even when it is off; 

  1. Alarm system 
  2. Smart entry system 
  3. Remote start/stop and trunk opener  
  4. Remote climate control On/Off  
  5. Built-in cam recorders 

2- What temperature kills a car battery? 

Both extremes of temperature are bad for a car battery. This means, whether its too cold or too hot, your car’s battery would suffer in both conditions.

Cold weather – battery capacity is reduced 
Hot weather – Battery life is reduced

3- Can a car battery die while driving? 

Yes, a car battery can die while driving but that doesn’t mean that engine will also stop running. You just won’t be able to start the car again after turning it off. The most probable cause behind this is a bad alternator, which is a component that powers the engine and charges the battery. 

4- Can a car run without a battery? 

Your car needs the battery for ignition and starting, so you cannot Start a car without a battery, but once it has been switched on, the car can run without a battery as the alternator provides the necessary power to the engine and other components. 

5- How to charge a completely dead battery? 

If a battery has completely died out, the best way to bring it back to life is “slow charging” it for 24 hours by plugging in. Mostly, a jump start would also give it a lease of life and then it can be driven for a while to charge, but even if that fails, plugging in is the only option. 

6- How long to leave the car running after jump? 

Ideally, a car should be left running for 30 minutes after a jump to ensure that it has been substantially recharged and all the components it is supposed to power are running fine. 


A car’s battery is one of the most important parts and a car can’t start of power its various components without it. It is also one of the most neglected items in terms of maintenance and a dead battery usually put people in trouble. 

It powers all the electrical components and a dying battery would make a car lethargic, while starting and using different features. If the battery dies, the best way is to either jump start it, or go for slow charging or replacement for surety and peace of mind. 

A battery would last a maximum of 4 weeks if left to sit, so it is ideal that it is either disconnected or the car is started every week to keep it charged. Regularly maintaining your car’s battery by topping up the electrolyte, and cleaning the corroded terminals can enhance its life.