Preventing and fixing a sulfated battery

If you have lead acid battery failure, you may have a sulfated battery, but what exactly is battery sulfation, and is it preventable?

Battery sulfation is the build-up of lead sulfate crystals within your lead acid battery's surface and pores, which can cause the battery to stop working. The good news is that most damage made through battery sulfation is reversible, and the problem itself can easily be prevented if you know the signs to watch out for.

What causes a sulfated battery?

Sulfation occurs when a battery does not receive a full charge, causing sulfate to build on the battery plates. If this is left untreated, the sulfation starts to hinder the chemical to electrical conversion, as the conductive area starts to reduce; this results in poor battery performance. 

Signs of battery sulfation include:

• Battery charging takes longer
• The battery overheats
• The battery charge will not last as long
• Significantly shorter battery life
• Complete battery failure

What causes battery sulfation in the first place?

Battery sulfation is commonplace in lead-acid batteries, and any small lead sulfate crystal formations will disintegrate during the regular battery charge. Still, it can lead to serious issues when a battery is:

• stored without it being fully charged
• overcharged
• stored above 75 degrees

Thankfully, battery sulfation can be reversible, it all depends on the type of sulfation your battery has; there is both a reversible and permanently damaged battery type. If you discover a sulfated battery in its early stages, then the damage is more likely to be reversible. The process of reversing a sulfated battery can be completed by a lead battery expert; never try to do this yourself.

What is the difference between permanent and reversible battery sulfation?

Permanent battery sulfation – If a battery has been on a low charge for a significant amount of time, meaning weeks and even months, it is unlikely that the sulfation damage can be reversed, even by an expert.

Reversible battery sulfation – the damage created by sulfation may be reversed by overcharging a fully charged battery with a regulated current of around 200mA. Over 24 hours, a battery terminal voltage can go up to between 2.50 and 2.66V/cell. The battery's temperature can be increased up to between 122-140°F, which can help the hardened crystals to dissolve within the battery.

Experts can use specific devices to prevent and reverse signs of battery sulfation on healthy batteries. These cannot always reverse signs of sulfation; we advise seeking professional assistance when dealing with battery sulfation prevention and reversal.

Ways to prevent a sulfated battery?

The first thing to be aware of is your battery storage in the prevention of battery sulfation. When you store your battery on a full charge, it must be charged enough so that it will not drop below 12.4 volts. The easiest way to do this is to apply a maintenance charge which prevents sulfates from building up. Batteries should be stored at room temperature of 68-75°C as anything above this will start to increase the rate of self-discharge in your batteries vastly.

Preventing battery sulfation is a clear and straightforward process; applying regular battery maintenance and following battery health best practices will result in you having healthy and long-lasting batteries. Never store your lead batteries with a zero charge, as this will undoubtedly lead to battery sulfation. Once the sulfation gets to the battery's lead plates it is difficult, if not impossible, to reverse the damaging effects; therefore, proper battery maintenance from the start is essential.