How to Fix a Sulfated Battery

Batteries are a common item that can start to fail over time. One sign of a battery failure is when it becomes sulfated. But, if your battery is sulfated, don’t worry – there is a way to fix it! This blog post will discuss what causes battery sulfation and how to fix a sulfated battery. We will also provide tips for preventing battery sulfation in the future. Keep reading to learn more.

Summary: If you have a sulfated battery, it is important to fix it as soon as possible. This will help your battery to work properly and last longer. Here are some tips on how to fix a sulfated battery: 1. Remove the battery from your device and clean it with a dry cloth. 2. Apply a sulfate-free battery cleaner to the battery and scrub it with a brush. 3. Reinstall the battery into your device and turn it on. 4. If the battery still doesn’t work, you may need to replace it.

How to Fix a Sulfated Battery

What Causes Battery Sulfation?

There are a few things that can cause battery sulfation, including:

Leaving a Battery Unused for Too Long

If you don’t use a battery for a long time, the lead plates inside it will start to corrode. This is more likely to happen in hot climates.

Discharging a Battery Too Low

If you use up all the power in a battery, sulfation can happen. This is because when a battery is only partially charged, the lead plates inside it aren’t being used as much as they could be. If you regularly use up a battery’s power until there’s only half of it left, sulfation is more likely to happen.

Using the Wrong Battery Charger

If you use a battery charger that is not designed for lead-acid batteries, sulfation can occur. This is because the charger can overcharge the battery, damaging the lead plates. In addition, battery sulfation is more likely to occur if you use a charger that is incompatible with your battery.

Use a Battery Charger

11 Steps How to Fix a Sulfated Battery

Step 1: Understand Sulfation in Batteries

Sulfation is a common issue that occurs in lead-acid batteries, such as automotive, marine, and deep-cycle batteries. This process involves the formation of lead sulfate crystals on the battery’s plates, which can hinder the battery’s ability to hold a charge and deliver power. Sulfation typically occurs when a battery is left in a discharged state for an extended period, is not properly maintained, or is subjected to high temperatures.

Step 2: Assess the Battery’s Condition

Before attempting to fix a sulfated battery, examine its overall condition. Check for any visible damage, swelling, or leaks. If the battery is in poor condition, it may be best to replace it rather than attempt a repair.

Step 3: Gather Necessary Tools and Materials

To fix a sulfated battery, you will need various tools and materials, such as:

  • A battery charger
  • A battery desulfator or pulse charger (optional)
  • Voltmeter or multimeter
  • Distilled water (if the battery is not sealed)
  • Protective gloves and safety glasses
  • Baking soda solution (to neutralize any acid spills)

Step 4: Check and Adjust Electrolyte Levels

If you have a non-sealed lead-acid battery, check the electrolyte levels in each cell. If the levels are low, carefully add distilled water to each cell until the plates are fully submerged. Be sure to wear protective gloves and safety glasses to avoid contact with battery acid.

Step 5: Charge the Battery at a Low Rate

Connect the battery to a charger and set the charging rate to the lowest possible setting, typically around 2 to 10 amps. Charging at a low rate can help break up the sulfate crystals and restore the battery’s capacity.

Step 6: Monitor the Charging Process

Keep a close eye on the battery during the charging process. Check the voltage regularly with a voltmeter or multimeter. If the battery’s voltage does not increase or if it begins to overheat, discontinue the charging process, as this may indicate that the battery is beyond repair.

Step 7: Use a Desulfator or Pulse Charger (Optional)

A battery desulfator or pulse charger can help remove sulfate crystals from the battery plates more effectively than a standard charger. These devices send high-frequency pulses through the battery, breaking up sulfate crystals and allowing them to dissolve back into the electrolyte. If you have access to a desulfator or pulse charger, connect it to the battery in addition to the standard charger, and follow the manufacturer’s instructions for use.

Step 8: Perform a Load Test

Once the battery has been charged, disconnect it from the charger and allow it to rest for a few hours. Then, use a voltmeter or multimeter to measure the battery’s voltage. If the voltage is above 12.4 volts for a 12-volt battery or 6.2 volts for a 6-volt battery, proceed to perform a load test.

To perform a load test, connect a battery load tester to the battery and follow the manufacturer’s instructions. A successful load test will indicate that the battery can deliver the necessary power under load and has been successfully desulfated.

Step 9: Recharge the Battery

After performing a successful load test, recharge the battery to ensure it is fully charged and ready for use. Be sure to monitor the charging process, as described in Step 6.

Step 10: Reinstall the Battery

Once the battery is fully charged and has passed the load test, reinstall it in your vehicle, boat, or equipment, ensuring that all connections are clean and secure.

Step 11: Maintain Your Battery to Prevent Future Sulfation

To prevent future sulfation issues, follow these best practices for battery maintenance:

a. Keep the battery fully charged: Regularly charge your battery and avoid allowing it to remain in a discharged state for extended periods. If you don’t use the battery often, consider using a trickle charger or a solar charger to maintain the charge.

b. Check and adjust electrolyte levels: For non-sealed batteries, regularly check the electrolyte levels and top off with distilled water as needed. This will help maintain the battery’s performance and prevent sulfation.

c. Monitor battery voltage: Use a voltmeter or multimeter to periodically check the battery’s voltage, ensuring that it remains within the proper range for its type.

d. Perform routine load tests: Regular load testing can help you identify any issues with your battery before they become severe, allowing you to address them promptly.

e. Store the battery properly: If you need to store the battery for an extended period, remove it from the vehicle or equipment and store it in a cool, dry location. Keep the battery fully charged and consider using a battery maintainer to keep it in optimal condition.

f. Keep battery terminals clean: Regularly inspect the battery terminals for signs of corrosion or dirt, and clean them as needed to ensure proper electrical contact.

g. Avoid exposing the battery to extreme temperatures: High temperatures can accelerate sulfation, so avoid exposing your battery to extreme heat whenever possible.

By following these steps and taking proper care of your battery, you can effectively fix a sulfated battery and prevent future sulfation issues. Regular maintenance and monitoring will help extend the life of your battery and ensure optimal performance. If you continue to experience issues with your battery despite these efforts, consult a professional mechanic or battery specialist for further assistance

How Long Does a Sulfated Battery Last?

Sulfated batteries typically last for 2-5 years. However, if the battery is not properly maintained, it may only last for 1-2 years. If your battery is sulfated, you can try to fix it with a sulfuric acid solution. However, if the battery is too far gone, you will need to replace it. Batteries are expensive, so it is important to take care of them. If you have a sulfated battery, you can try to fix it with a sulfuric acid solution.

Can You Charge a Battery With Sulfation?

Yes, you can charge a battery with sulfation. However, the charging process will take longer than usual. Therefore, it is important to monitor the charging process to ensure that the battery does not overcharge. If the battery voltage exceeds 14 volts, disconnect the charger and let the battery cool down. Once the battery has cooled, you can reconnect the charger and continue charging.

Tips and Warnings on How to Fix a Sulfated Battery:


  1. if your battery is starting to show signs of sulfation, don’t wait to fix it. The sooner you take action, the better the chance of saving your battery.
  2. If you have an old lead acid battery you’re planning on using for a car starter battery, check it for sulfation first.
  3. If you think your battery may be sulfated, take it to a professional to have it checked and serviced.
  4. Use distilled water when adding water to the cells.
  5. Check the battery regularly for leaks.
  6. Keep the area around the battery clean and free of debris.
Adding Water to The Cells

Disconnect the negative terminal before disconnecting the positive terminal.


Never overcharge a battery. This can cause the battery to catch fire or explode.

  1. Never attempt to disassemble a battery. Batteries contain sulfuric acid, which is dangerous.
  2. Never throw away a battery. Batteries must be disposed of properly to avoid environmental contamination.
  3. Be sure to use gloves when working with batteries.
  4. Do not overcharge the battery.
  5. Do not short circuit the battery.
  6. Do not expose the battery to extreme heat or cold.
  7. Do not use a damaged battery.
  8. Do not attempt to repair a battery yourself if you are not qualified to do so.

Frequently Asked Questions

Is a Sulfated Battery Ruined?

A sulfated battery is a type of lead-acid battery that has been treated with sulfur dioxide to prevent it from corroding. While this treatment may be effective in the short term, over time it can actually cause damage to the battery.

Sulfated batteries are often used in applications where corrosiveness or sensitivity to other chemicals is an issue, such as marine and automotive powertrains. The addition of sulfur dioxide not only helps protect the cells from corrosion but also prevents them from forming explosive hydrogen gas bubbles.

However, over time these bubbles will grow larger and burst, potentially damaging both the cell walls and internal components of the battery. In extreme cases, this can even lead to a full-blown explosion!

It is important to keep track of your sulfated batteries so you can identify any signs of deterioration and address them before they become too serious.

What Causes a Battery to Sulfate?

A battery can sulfate when it is drained of its electrolyte and contains sulfate crystals. These crystals can make the battery swell up and cause it to leak. When this happens, it is important to disconnect the battery from the device and allow it to discharge completely before recharging.

Can a Sulfated Battery Be Saved?

A sulfated battery is a type of lead-acid battery that has been treated with sulfur to prevent oxidative degradation. Sulfation creates an electrochemical barrier that can protect lead plates from external damage, including pollution and excessive moisture.

Unfortunately, sulfated batteries are not as strong as regular lead-acid batteries and may not last as long. They also require more frequent charging due to their reduced capacity, so it’s important to choose the correct model for your needs. If you need a high discharge rate, then a sulfated battery might be best suited for you. And if you only need short-term power (such as in emergencies), then a standard lead acid battery would be more efficient overall.

What Voltage is Needed to Desulfate a Battery?

The voltage needed to desulfate a battery will vary depending on the type of battery, the battery’s age, and the method used to desulfate the battery. However, generally speaking, batteries that are 6 or 8 volts need a higher voltage to desulfate them effectively than batteries that are 12 or 24 volts.

Final Words

This article has provided tips on how to fix a sulfated battery. So, if your battery is sulfated and beyond help, don’t worry. You have options. You can replace the battery with a new one or send it in for reconditioning. Either way, acting quickly is important because a sulfated battery will only get worse over time. Have you had experience with a sulfated battery? Let us know in the comments below.

You Can Check It Out Fix a Dead Battery Cell

Leave a Comment