Can You Revive a Completely Dead Car Battery?

Ross Ballot
by Ross Ballot
Photo Credit: Roman Zaiets / Shutterstock.com

A dead car battery can leave you stranded, which can be inconvenient at best or downright dangerous at worst. In many cases you can jump-start the vehicle, but that’s not always possible. Reviving a completely dead car battery can be challenging, and it's not always guaranteed to work. However, the worst you can do is try.

Photo Credit: LizzavetaS / Shutterstock.com

Attempting to revive a completely dead car battery can be done by following these steps:


Connect the dead vehicle to a functional vehicle:


  • Use jumper cables to connect your dead battery to the battery of another running vehicle.
  • Make sure both cars are turned off.
  • Connect the positive (+) terminal of the dead battery to the positive terminal of the working battery.
  • Connect the negative (-) terminal of the working battery to a metal part of the car with the dead battery (not directly to the negative terminal of the dead battery).
  • Note: You can also use a portable jump starter or jump box to replicate this if that’s what you have available to you, or if the battery of the dead vehicle is not accessible with jumper cables (such as if it is parked nose-in against a wall with cars on either side, as can be the case in parking garages).


Start the Working Car:


  • Start the engine of the working car and let it run for a few minutes.
  • Attempt to Start the Dead Car: Try to start the engine of the car with the dead battery. If it works, disconnect the jumper cables. If not, wait a few seconds and try again to start the dead car.
  • Charge the Battery: If the jump-start is successful, drive the car for at least 20-30 minutes to allow the alternator to recharge the battery.
  • If the jump-start doesn't work, the battery might be too far gone, and you may need to replace it. Additionally, consider checking for other issues such as corroded terminals or a faulty alternator. If you're unsure or uncomfortable with the process, it's advisable to seek assistance from a professional mechanic.


The chances that a completely dead battery can be revived aren’t always in your favor, but in some instances it is possible to bring the dead battery back to life. You can get a sense of the condition of the battery by using a battery tester, and determining the battery’s voltage when the vehicle is off (and ideally when it is running as well).

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The TB6000Pro is able to test your battery before charging, which gives you an inside look at your battery’s health. It also boasts a 9-step smart charging feature (diagnosis, desulphation, pre-charge, soft start, bulk charge, absorption, analysis, recondition, maintenance) which eliminates the worry of potentially over charging. It also provides both a pre- and post-charging report so you can see how much the battery has been improved.


With the TB6000Pro, you can monitor the status of your charging using an app on your phone. Through this app, you have access to advanced settings like voltage and current adjustment.


The TB6000Pro does more than charge your battery…it also repairs it. It utilizes pulse-width modulation to help break down the sulfates in your battery, which means improved battery resistance and longer service life.


Compatible with 6V and 12V lead-acid batteries and 12V lithium batteries, the TB6000Pro can keep virtually any vehicle battery charged and ready to go.


Portable jump boxes like this TopDon JS2000 unit can start most vehicles, though a completely dead battery may require the use of "Boost" mode or similar.

Why does a car battery die?


Several factors can contribute to a car battery dying. Here are some common reasons:


Age:

Car batteries have a limited lifespan, typically ranging from 3 to 5 years. This timeframe can vary significantly from use (or lack of use) and operating conditions. As a battery ages, its ability to hold a charge diminishes. This is no different from how your smartphone starts to deplete its battery more quickly after you’ve had it for a few years.


Extreme Temperatures:

Both extremely hot and cold temperatures can affect a battery's performance. High temperatures can cause fluid evaporation, while cold temperatures can reduce the battery's ability to provide power.


Battery sulfation:

Modern vehicles generally use lead-acid batteries, which function thanks to sulfuric fluid within their confines. When the battery is discharged, i.e. in use with a load on it, the sulfate itself (which is made of sulfur and lead) attach to the plates inside the battery itself. The opposite of this crystallization process is done when a battery is being charged. If a battery is discharged beyond a certain point or sits too long, the crystals hamper the ability for electricity to flow through the battery, which results in a dead battery. BatteriesPlus notes that overcharging at a current of ~200mA (milliAmps) for about a 24 hour period has a chance of reviving the dead battery, and that doing so “allows the battery's terminal voltage to rise between 2.50 and 2.66 volts per cell, which helps to dissolve sulfate crystals.” A specific charger is needed for this, and they usually come with a “Recovery” mode. Still, there’s no guarantee this will be successful.


Parasitic Drain:

Some electrical components in a car can continue to draw power even when the engine is off. This parasitic drain can slowly deplete the battery over time.


Charging System Issues:

A malfunctioning alternator or voltage regulator can lead to an insufficient charge being supplied to the battery, causing it to die.


Corroded or Loose Battery Connections:

Corrosion on the battery terminals or loose connections can hinder the flow of electricity between the battery and the vehicle's electrical system.


Faulty Charging:

If the battery is not being properly charged during vehicle operation, it can gradually lose its charge. This may be due to a faulty alternator, loose belt, or other charging system issues.


Defective Battery:

Sometimes, batteries can be defective from the manufacturer or may develop internal faults that lead to a loss of charge.


Short Drives:

If you only take short trips without giving the battery enough time to recharge fully, it may not regain its full charge before the vehicle is shut off.


Leaving Lights On:

Leaving headlights, interior lights, or other electrical devices on when the engine is off can quickly drain the battery.


Faulty Components:

Issues with other vehicle components, such as a malfunctioning starter or ignition switch, can contribute to battery problems.

Regular maintenance, periodic battery checks, and addressing any electrical issues promptly can help prevent unexpected battery failures. If you experience recurring battery problems, it's advisable to have your vehicle inspected by a professional mechanic.

Ross Ballot
Ross Ballot

Ross hosts The Off the Road Again Podcast. He has been in the off-road world since he was a kid riding in the back of his dad’s YJ Wrangler. He works in marketing by day and in his free time contributes to Hooniverse, AutoGuide, and ATV.com, and in the past has contributed to UTV Driver, ATV Rider, and Everyday Driver. Ross drives a 2018 Lexus GX460 that is an ongoing build project featured on multiple websites and the podcast.

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