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What is Battery Sulphation?

This entry was posted on 11/12/2019 09:00:00 AM by Valen

What is battery sulphation

How many times have you said to yourself, "My battery won't take or hold a charge" or "I'm losing duration of battery use time!"

More often than not, battery sulphation has occurred. If the sulphation becomes excessive and forms large crystals on the plates, the battery will not operate efficiently. 

In this blog, the experts at Valen take you through what battery sulphation is, how to, potentially, repair it and how to prevent it. 


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What is Battery Sulphation?

Battery sulphation occurs when a sealed lead-acid battery is deprived of a full charge. In regular use, battery's are getting sulphated all the time. 

When a battery is being discharged the lead active material on the plates will react with the sulphate from the electrolyte forming lead sulphate crystals on the plates. Small sulphate crystals form, but these are normal and aren't harmful. 

During prolonged charge deprivation and battery abuse, the lead sulphate will become hard and have high electrical resistance. This leads to the development of large crystals that reduce the battery's active material, which is responsible for the battery performance. 

This sulphation will cause:

  • longer charging times, 
  • excessive heat build-up, 
  • shorter run times between charges, 
  • reduce the batteries life; and
  • cause premature battery failure 


Different types of Sulphation

There are two types of battery sulphation: soft sulphation and hard sulphation. 

Soft Sulphation

If a battery is serviced early, reversible sulphation can be corrected by applying an overcharge to an already fully charged battery in the form of a regulated current. The battery terminal voltage is allowed to rise for about 24 hours. The overcharge increases the battery temperature, which further helps to dissolve the crystals. 

This method should only be completed by someone with seasoned experience working with batteries. 

Hard Sulphation

Occurs when a battery has been in a low state-of-charge (SOC) for an extended duration of time. Hardened sulphation also forms in a lead-acid battery that is continually being cycled in the middle of its capacity range and never recharged to 100%. 

Looking at the voltage discharge curve of a battery can be a subtle indication of whether the battery can be recovered or not. If a fully charged battery retains a stable voltage on discharge, chances of correction are better than if the voltage dropped rapidly with a load. 


How do I prevent Battery Sulphation?

The best way to prevent sulphation is to practice correct battery maintenance and follow charging best practices. 

Valen recommends to always recharge the battery immediately after discharge. We also recommend checking the batteries impedance with an Impedance Battery Tester periodically. 


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Want to get the maximum life possible from your deep cycle batteries?

For tips on how to make sure your deep cycle batteries last for as long as possible, check out our blog post How can I prolong the life of my deep cycle VRLA batteries? 

Or you can always contact our knowledgeable team for additional support. 

Click here to get in touch, or you can schedule a no-obligation 15-minute phone call with one of our experienced battery experts. 

Written by Valen

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