ACDC Express

Lead Acid Batteries Keep Dying? Beware of Battery Sulphation

Battery Sulphation can be avoided by opting for Lithium-Ion batteries.

Do you have a lead acid battery that died before the end of its expected lifespan? Or are you noticing that your batteries aren’t lasting as long as they used to, resulting in a loss of backup power before load shedding is over? If your answer is yes to any of these questions, you might have a case of battery sulphation giving you a headache.

What is Battery Sulphation?

If you have a lead acid battery, lead sulphate crystals are formed when a battery is being used as a power source. This is part of the chemical reaction that allows a battery to store energy to be utilised later. These crystals are small, forming in the pores of the lead plates inside the battery. If the battery is charged, these tiny crystals dissolve, returning to the solution inside your battery.

The real problem occurs when batteries are deprived of a charge for a long period or aren’t fully charged before being used again. The tiny crystals of lead sulphate turn into a stable crystalline structure on the negative plates. If caught early enough, the crystals can be dissolved with proper techniques or by a professional. The longer the crystals are left, the larger and harder they become and eventually the sulphation is permanent.

Types of Battery Sulphation

Battery Sulphation is split into two types. There is soft sulphation, which is when it is still reversible by servicing the battery. Then there is hard sulphation, which is permanent. The only way to determine which type of sulphation is present is by doing a voltage test of the battery. If a fully charged battery retains a stable voltage profile on discharge, the sulphation is likely to be soft. If the voltage drops rapidly with load, then there is a high chance the sulphation is hard.

What Causes Battery Sulphation

Any lead acid battery (remember that gel batteries are still lead acid batteries) will have sulphation during its lifetime, as it is part of the chemical reaction that allows energy storage. However, there are ways to avoid it becoming permanent. Depriving a battery of a full charge, leaving it undercharged, storing it at high temperatures, not using them for long periods of time or storing them without fully charging them first all lead to quicker battery sulphation.

If you have a wind or solar system providing power to your lead acid batteries, they could be left without a full charge. Similarly, if your backup power system uses lead acid batteries, they might not be fully charged by the time load shedding kicks in again, which will allow those tiny crystals to start settling. 

What are the Effects of Battery Sulphation

Battery sulphation doesn’t immediately result in a dead battery. As more and more sulphate forms on the negative lead plate, there is a reduction in the conductive area inside the battery, resulting in a reduced capacity. If you notice longer charging times, shorter battery life or your batteries feeling a lot hotter than normal, these can all be indications of permanent sulphation.

How to prevent Battery Sulphation

Lead acid batteries should always be kept at a charge of at least 12.4 Volts. It is recommended to store your batteries somewhere cool. Most manufacturers recommend not exceeding 24 degrees, which can be quite a challenge for sunny South Africa!

If you want to avoid battery sulphation completely, a lithium-ion battery is a potential option. While these batteries do cost significantly more than their lead acid counterparts, the longer cycle count and lifespan of a lithium-ion battery make them the cheaper option in the long run. Otherwise, make sure your batteries are always fully charged and not left discharged for long periods to get the most out of them!

Visit our specials page to find the best deals on a wide range of batteries!

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