How to Bring a Deep Cycle Battery Back to Life

All DC batteries have a limited lifespan after which they cannot supply energy at all. Deep Cycle Battery is such a type of electrolyte-powered battery.

How to Bring a Deep Cycle Battery Back to Life

Deep Cycle Batteries are designed for providing high electrical bursts consistently for a long period of time. It supplies a high electrical current continuously till it gets discharged to 85%.

For such rough usage, Deep Cycle Battery tends to wear off its longevity very early. But knowing the exact procedure about how to bring a deep cycle battery back to life it can be further used for two to three years at a stretch. In the next section, the step-by-step procedures for restoring a dead deep cycle battery would be stated.

The Process of Bringing a Deep Cycle Battery Back to Life

The following simple yet effective procedures would help you to revive a Deep Cycle Battery. Restoring is better than replacement. 

Cleaning Up the Battery

How to Bring a Deep Cycle Battery Back to Life
  • Collect some paper towels and dry microfiber cloth. Batteries tend to corrode over time of usage. 
  • Clean the top, edges, and every corner of your battery initially using a paper towel. It is done to remove all the solid dirt and debris.
  • Nextly, pour some Baking Powder (Sodium bicarbonate) into distilled water to make a solution of the cleaning agent. 
  • Finally, Soak the solution using the cloth and clean the tight spots and surroundings of the cell lids thoroughly.

Opening Up the Cell Caps

How to Bring a Deep Cycle Battery Back to Life
  • For your safety concerns, wear protective gear such as transparent plastic goggles and silicon gloves for safety. 
  • Twist the cell cap counterclockwise to open each lid. 
  • Use a flat head screwdriver to peel the cap off from the cell lid. 

Visual Inspection of electrolyte or water levels

How to Bring a Deep Cycle Battery Back to Life
  • Visually check all the cells of the battery if those contain sufficient amounts of electrolytes or water or not. 
  • You can also use a litmus paper-covered long stick to know the exact level of electrolytes inside the cells.

Inspection of Voltage in each cell 

how to Inspect the Voltage of each battery cell
  • Set up a voltmeter and put the connector inside each cell.
  • Record the reading of the voltmeter in the cell. 
  • Check if all the cells have equal readings. If all cells have equal but lower voltmeter reading then your battery has been completely drained off the power.
  • If you get a comparatively lower voltage reading in some of the cells than others, then your battery has been weakened over regular use.

Use the Load Tester Device

How to Bring a Deep Cycle Battery Back to Life
  • Load Tester Device is used to check the battery health of Deep Cycle Batteries.
  • Use rubber gloves before proceeding to the next step.
  • Connect the terminals of the load testing device to the positive and negative terminals of the battery.
  • Switch on the device and hold for 8-10 seconds.
  • Check the dropping of the voltage reading in the device.
  • Complete the previous steps two to three times before proceeding to the next step.
  • Calculate the difference between initial and final reading on the Load Testing Device. 
  • The result will allow you to know if the battery is dead or has weak health. 

Inspection of Specific Gravity 

Inspection of Specific Gravity
  • Insert the Hydrometer in each cell and check the reading.
  • Good Batteries show reading in the hydrometer above 1400.
  • Weak batteries have a reading range of 1100-1200
  • Dead batteries show a reading below 1100. 

Drain all the leftover Acid

Drain all the leftover Acid
  • After wearing protective goggles and gloves, gently drain all the acidic water.
  • Lastly, properly dispose of the water. 

 Cleaning the Cells

how to  Clean RV car battery Cells
  • Add 3-5ounces of Baking Powder (Sodium Bicarbonate) into a gallon of distilled water.
  • Pour the solution inside the cells equally and do it carefully as Baking Powder solution can be corrosive. 
  • Shake the battery to distribute the solution equally inside the cells and clean it thoroughly.
  • Drain the solution carefully and dispose of it. 
  • Dry up the cells and surface of the battery using dry paper towels.

Feed the cells with Distilled Water

how to Feed the battery cells with Distilled Water
  • Distilled water is demineralized water. It does not contain any minerals which cause corrosion in Deep Cycle Batteries. 
  • Do not use tap water or other types as it may damage the lead plates permanently.
  • Fill up each battery cell with distilled water to the mark. Avoid overfilling because it may contain acid and may cause contamination.  

Desulfation Process

Desulfation Process of a battery
  • Close all the lids of the battery cells properly.
  • Connect the terminals of the Deep Cycle Battery with a smart automatic charger.
  • Plug in the charger to the wall socket having 120 output voltage. 
  • Select the desulfation profile in the charger and switch on the device to initiate the desulfation process.
  • Low power with very high frequency and high voltage are passed through the cells. These electrical impulses form crystals on the Lead surface to remove the deposited Sulphur. 
  • The free sulfur dissolved the solution.


how to Recharge a rv battery
  • Connect the battery with a regular charger.
  • Charge it overnight for 24 hours for three days.
  • At this point, the battery should be up and running like before. 

Reviving the Battery Using Epsom Salt

Reviving the Battery Using Epsom Salt
  • Epsom salt is a very strong electrolyte. It produces enormous positive and negative ions in a distilled water solution.
  • Heat a gallon of distilled water for 30 mins at 65 degrees Celsius temperature. 
  • This increases the solubility of the solute in the solvent,
  • Add a decent amount of Epsom Salt in a gallon of distilled water and stir it thoroughly.
  • Pour the solution in the cells of the battery with equal range.
  • Recharge the battery overnight using an automatic charger.

Frequently Asked Questions

This section will allow you to understand the facts about reviving and restoring a dead battery from a third person’s perspective.

Is it possible to revive a dead battery with Epsom salt?

It is possible to restore dead Deep Cycle Batteries with Epsom Salt solution. Epsom Salt can produce highly ionized charged particles in a solution. The rapid flow of the free ions in the solution can revive a dead battery. You must use the proper charging profile for the restoration process.

How to bring a deep cycle battery back to life with Epsom salt?

Epsom salts produce ions of Magnesium and Sulfate in distilled water solution. When recharged at high voltages the free ions become eligible to pass current. And thus Epsom salt can revive a dead Deep Cycle Battery.

How many years will a deep cycle battery last?

Deep cycle batteries are designed to last for 3-4 years being regularly used. At an optimum temperature and moderate weather conditions, a deep cycle battery can show an extended lifespan of at least five to eight years.

At what voltage is a deep cycle battery dead?

If the voltmeter shows unequal or below 1V voltage reading in each cell then the battery is considered to be dead. Again if the combined cell voltage is observed less than 10V, then reviving the battery is not possible. 


Deep Cycle Batteries are quite expensive. These batteries have a limited warranty and are not designed to last long such as a Li-ion Battery. Therefore, the deep cycle batteries require replacement for continuing the work.

Some simple procedures with cheap material can revive a deep cycle battery. It is good to know how to bring a dead battery back to life rather than buying a new one.

Thus, we can conclude that it is recommended to replace a dead battery. But, with proper inspection and following some simple process can save your money. Moreover, it will add a decent amount of time to the battery’s lifespan at a time of crisis.

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