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How long can a car run with a dead battery?

Car batteries do not last forever. They can last three or five years, but will eventually degrade and fail, often without the car owner noticing. An especially cold night can finish off a battery that was already played, discharge it completely, or even render it useless.  In such a case, this problem can occur. Let’s find out how to face it.

How long a car can run with a dead battery cannot be stated with certainty. It depends on various factors.

How long can a car run with a dead battery?
  • If the battery is dead while driving on the highway, you can drive as far as until you turn off the engine or run out of fuel.
  • If the battery is dead while driving on a suburban road, you can until the engine is turned off.
  • Even if the battery dies, you can still travel if you can recharge it.
  • Also, you can go if the alternator can produce enough current to maintain the running voltage.

But if the car battery is dead, it may become unusable within 1 or 2 months, and the battery has to be replaced soon. However, there are other things you should consider before replacing the battery. 

Before talking about this, it is better to know about the car battery. 

The function of the battery  

How long can a car run with a dead battery?

The function of the battery is to provide the necessary electricity to make the starter motor work. If the car runs out of battery, you will not be able to start until it is charged. 

How long does a car battery last?

It is generally assumed that a car battery should last a minimum of four years with continued use of the vehicle. Whenever the car is driven, the battery is charged by a chemical process from the combustion of gasoline or diesel in the engine of the car.

In this way, it is filled with energy to provide water to the vehicle’s electrical system, as well as to the car’s engine in the ignition process.

Signs that your car battery is dead

How long can a car run with a dead battery?
  • Indications

Many indicators are warnings of a car battery failure. If the engine slowly runs when started, this usually means that a battery cell is dead or not producing. A battery is low when left overnight and has a hard time starting the engine, but runs fine the rest of the day, is also showing signs of failure. A battery that is low on water in one or more cells could soon fail.

  • Battery Composition

A battery consists of a series of cells that increase in amperage as the voltage increases. Every cell takes the indicated amperage supply. If the battery has 650 cranking amps, this number is for all the cells collectively. If any of these wear out, the amperage drops significantly. 

  • Battery sizes and IDs

Each battery will have a sticker on the top with a picture of the CCA as CCA 650. It means the battery can produce 650 amps for 30 seconds at 0 degrees Fahrenheit (-17 degrees Celsius). The most important thing is the RC figure on the decal.

It is the reserve capacity of how long the battery can run the car if the alternator fails. And it Indicates how long the battery can produce 25 amps until it drops to 10.5 volts. An emergency like a failed alternator can make a big difference in how the vehicle will travel. 

  • Battery demands

Another indicator is having a shortened cell inside the battery. In this case, the vehicle’s battery will be extremely low or dead in the morning or after it sits for a while.

When the vehicle is jump-started, and the battery is charged up again, it may be fine for the rest of the day until it is dead for some time. In other words, a short in one or more cells will slowly discharge the battery over time.

  • Checking Battery Utility

An ordinary voltmeter is the most effective and easiest way to check a dead battery. 


  1. First, Turn it on to 20 volts and place the red lead on the positive battery connector and the black on the negative terminal. The voltage should be between 12.5 to 12.75 volts. If it is not in that range, check the water level in the battery and correct it if necessary. 
  1. Then, change the battery or start the car with a jumper. Check the voltage across the battery again with the engine running. 

See if the alternator is working to give voltage and charge to the battery. 

  1. The voltage should now be at or very close to 14.5. 
  1. Turn on the AC and low beams to see if the voltage stays the same or similar.  

If it is 13.5 or less, the alternator is bad, and it causes the battery to look bad, as the alternator is not charging the battery.  And you’ll need to check the battery cells If the alternator is okay. 

  1. Turn off the engine. (You may need a helper for this review.) Have the helper start the engine while paying close attention to the voltmeter. If the voltage drops below 10 volts When cranking, it means there is a bad cell. 
  • Expired battery
How long can a car run with a dead battery?

Yes, batteries have expiration dates here; therefore, if it is approaching three or five years of its useful life, it might be time to install a new one. Make sure to take a look at the expiration date of the rear battery and check if it is nearing the end of its life. If that’s the case, consider installing a new one because you won’t have any other solutions.

Thus, if you see one or more of the above characteristics, you should consider replacing the battery.

How long can a car run with a dead battery?

In addition to the battery, battery fault conditions can also occur when the alternator fails. For that, you need to take the car to a repair shop and get it checked.

We have prepared a simple chart to help you easily understand the signs of a dead car battery and their causes.

Battery problemWhy is this happeningWhat to do
The battery drains quicklyDrop in electrolyte level.
Destruction of active plates.
Add electrolytes if possible. Replace battery.
Gray light plaque on the platesDeep charge or suboptimal battery charge mode.Carry out a battery desulfation charge or replace the battery.
Hull bulged (no damage)Excessive gas formation due to overcharging or a drop in the electrolyte level.
Clogged ventilation holes.
Eliminate the cause of the overcharge, restore the electrolyte level and charge the battery.
Clean ventilation holes.
Cracks and streaks on the battery caseExcessive pressure inside the housing due to increased gas formation.
Freezing of the electrolyte due to a drop in density.

Replace battery.
Low voltage and electrolyte density after chargingSulfur from the electrolyte turns into lead sulfate and settles on the plates, but cannot dissolve back due to excessive crystal formation, so the density of the electrolyte decreases. 
It is also possible for the electrolyte to boil away.
Charge the battery and adjust the density of the electrolyte If that doesn’t help, change the battery.
Electrolyte dark or with sediment
Destruction of the active mass of the plates or the formation of insoluble sulfate.The battery needs to be replaced as it is beyond repair.
Plaque on battery terminalsBoiling of the electrolyte during charging due to battery sulfation.Top up with distilled water, and charge with desulfation, if it doesn’t help, change the battery.

Ноw tо ехtеnd bаttеrу lіfе?

How long can a car run with a dead battery?
  • It is wise to avoid short runs and frequent engine starts if at all possible.
  • Dо nоt ѕtоrе thе bаttеrу іn а dіѕсhаrgеd ѕtаtе, іt muѕt оnlу bе ѕtоrеd іn а сhаrgеd ѕtаtе.
  • Dо nоt brіng thе bаttеrу tо а dеер аnd соmрlеtе dіѕсhаrgе.
  • Сhесk thе tеnѕіоn аnd соndіtіоn оf thе аltеrnаtоr bеlt.
  • Іn wіntеr, аnd еѕресіаllу іn ѕеvеrе frоѕtѕ, оthеr саr оwnеrѕ rеmоvе thе bаttеrу аnd tаkе іt tо а wаrm rооm. And it is better. Dо thе ѕаmе thing.
  • Uѕе ѕресіаl “wаrmіng” dеvісеѕ fоr bаttеrіеѕ durіng thе wіntеr реrіоd оf ореrаtіоn. such as соvеrѕ, thеrmаl саѕеѕ, thеrmаl tаblеtѕ, thеrmаl bохеѕ, еtс.
  • Аnd, fіnаllу, thе mоѕt іmроrtаnt thіng: саrrу оut реrіоdіс (аnd аt thе ѕаmе tіmе ѕуѕtеmаtіс) dіаgnоѕtісѕ оf thе оn-bоаrd еlесtrісаl ѕуѕtеm оf уоur іrоn hоrѕе, аnd thе Аutоbооkіng wеbѕіtе wіll hеlр уоu fіnd а ѕuіtаblе ѕресіаlіzеd ѕеrvісе ѕtаtіоn іn уоur сіtу.

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