How to Bring A Deep Cycle Battery Back To Life?

Deep cycle batteries which are also known as lead-acid batteries are mostly used for recreational vehicles example of which is a boat camper. They are ideal where recreational vehicles require much power for a little amount of time.

When deep cycle batteries are left idle for a long time, they produce sulphite crystals. This is not ideal as the sulphite crystal produced keeps the plates separate from the battery acid, a condition that leads to short discharge and also fast charging, this, in turn, renders the battery useless and ineffective.

When this happens, what do you do? Do you go ahead and purchase another one? Certainly not, not when something can be done to bring it back to life. That is why this article was written to educate you on how to bring a deep cycle battery back to life.

However, one of the first things you must know before attempting to resuscitate your battery is the voltage of the battery. Most batteries are either 6v or 12v. The knowledge of this comes in handy as we go along.

Let’s begin, shall we?

As earlier stated, after a while, most batteries go flat and will be unable to provide the kind of power needed by machines or vehicles. For some, the easiest way to solve this problem is to buy a new battery altogether. This, however, is expensive, you can resuscitate your dead battery and hence don’t need to buy a new one thereby saving a lot of money in the process.

Table of Contents

Guides on How to bring a deep cycle battery back to life?

There are five steps to this but note that there is a need for caution to be applied. Ensure you reread each step to be confident of doing the right thing.

The steps involved include:

Step 1. Clean the battery

As batteries get older, they encounter the problem of corrosion. To recognize a corroding battery, you will see the appearance of white powder on the exterior of the battery. Note that, the whitish substance is toxic and should be washed off from the battery before proceeding further. Also, never forget to wear work gloves and safety goggles to protect your eyes and hands from direct contact with the chemical.

To clean the battery, you will need to get a gallon of water and baking powder (one pound), pour it in a basin, and mix thoroughly. The baking powder is essential as it renders the acid gotten from the battery harmless. Check if the battery is very dirty or filled with grease. If that’s the case, then add soap to the mixture.

After this, take off the terminals of the battery by employing the use of two wenches. Ensure you are using the right size. Once you have removed battery terminals, thoroughly clean the clamps as well as the terminals using the already prepared mixture and a toothbrush.

Once this process is completed, clean your battery with dry clothe and after that, check for cracks or damages. If all checks out mechanically, then go ahead and rub petroleum jelly on the terminals. Another way to do this is by using commercial protection spray on the terminals before reattaching the clamps.

Step 2. Detach the cell lid of the battery

Once you are done cleaning the battery, the next phase in learning how to bring a deep cycle battery back to life involves the restoration of the process. Before doing this, you may want to get a screwdriver as it will be needed to remove all the cell lids of the battery. A needle-nose peril can also be used in place of a screwdriver during this procedure.

Also, do not forget to put on your work gloves as well as your goggles; they are for your safety as it protects you from acid. In case you are unaware, this acid can eat into your clothes and burn your skin, so again, wear the protective materials mentioned and do be careful throughout the entire process.

Also, while detaching the cell covers from the battery, it’s important to prevent dirt and debris from getting into the battery cells. Ensure a rag is at hand to make it easy to wipe off any mess created while working.

Step 3. Filling The Battery Cells with water

Here, you will need to ensure that only distilled water is used as tap water or any other form of water no matter how clean it may seem has minerals in them that can cause corrosion and we don’t want that. Fill each cell with the water completely.

Note: if you don’t fill the cells with distilled water, the oxygen and hydrogen remaining in the cell can cause a spark or explosion of the battery.

However, while filling the cells with the distilled water, ensure you don’t overfill them as the water coming out of the cell will contain acid. The amount of water to be added to the cell depends on the size of the battery and also the level of acid in it. A 6v battery will require less water than a 12v battery.

Step 4. Connect the battery to a battery resuscitator

After filling the cells with water, don’t be surprised that your battery should immediately start working. However, it’s best to have it charged with a regular battery charger. If it starts charging, continue charging it for a while, but if it doesn’t, then you will need to purchase a battery rejuvenator.

The rejuvenator can pulsate power through the plates of the battery and then cause the accumulated sulfate to break into pieces. When this happens, and the sulfate has been removed, it then becomes possible to charge your battery once again.

Step 5. Test the voltage of your battery

After you are done charging your battery, check how much charge your battery is holding, you can do this with the aid of a voltmeter. After that, allow the battery to sit for a few days. Again, check the voltage of the battery using your voltmeter.

If after checking, both checks give you the same result, then it’s as good as new and can be used again. Now install your battery back into your vehicle. Ensure you check the voltage of the battery from time to time to ascertain that it’s holding the same charge.

This is just one way; let’s explore another method and learn how to bring a deep cycle battery back to life.

Restoring deep cycle battery with an Epsom salt

This has been discovered to work effectively. Before restitution of the battery was made, the voltage was tested and found to be 10.5v with no load and an underload of 2v. After Epsom salt was used, it read 13.9v, while the under load maintained a 12.9v reading for about 15 sec.

Items Needed:

  • Epsom salts
  • Plastic funnel
  • Distilled water
  • Safety goggle
  • Rubber gloves
  • Voltmeter
  • Battery charger
  • Drill (if the battery is sealed)
  • Plastic plugs (if the battery is sealed)

To revive your deep cycle battery using an Epsom salt, take the following steps:

  • First things first, test the battery to see if it will respond to restitution. For it to be revived, it needs to read within the range of 10v to 12v; if it reads less than 10v, then it’s a waste of time, it cannot be revived. However, if all checks out, then proceed to step two.
  • Heat about half a quart distilled water to a temperature of 150oF, after that dissolve about 7 to 8oz of Epsom salt in the heated water.
  • Detach the lids of the battery. If yours is sealed, then drill through the shadow plugs located on the battery cells.
  • Drain out any fluid found in the battery. While doing this, you need to apply caution as the fluids are acidic. Once done, pour enough of the Epsom salt solution into each of the battery cells. This can be done using a plastic funnel.
  • Replace the caps of the battery or insert plastic plugs into the drilled holes on the battery. After that, shake the battery properly to ensure the Epsom salts solution evenly distributes to all parts of the cell.
  • The final stage involved in this method is to recharge the battery. Do this using a slow charge for about 24 hours after which you can re-install your battery into your car.


  • The battery should be placed on the charger for about three to four nights to restore its full capacity
  • If you won’t use the battery for some time, its best to put it on a trickle charger, this minimizes loss of performance as the longer a battery is stored, the more it loses it charges and instead allows sulfur to be formed on the lead plates.


Now that you know how to bring a deep cycle battery back to life, you need not discard your old batteries for new ones. Why don’t you try reviving it first, it just might come back to life and if it doesn’t only then should you get a new one. So, save yourself some money, revive your dead batteries and have them working again.

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