A common question that automotive dealers might be asked by their customers is why their ‘new’ car battery has failed when it has seldom, or never, been used.  

While this is an awkward question in that it suggests a defective product might have been sold in the first place, there is a reasonable explanation that doesn’t relate to the poor quality of the battery – but rather how long it has been stored or inactive.  

Barnabas Gwarisa oversees environmental and quality control at Probe, South Africa’s largest importer of automotive batteries.  With over fifty years of experience in distributing and providing aftermarket support for many international brands, Probe is well versed in problem shooting and advising customers on optimal battery storage.

The company is committed to providing quality and service, availability and technical expertise for every power need – the complete power package throughout the lifespan of a vehicle. 

Barnabas says that the problem with battery failure almost always lies in the issue of sulphation.  He explains, “The chemistry in a battery requires reversible reactions that maintain a state of equilibrium as the current flows, meaning that the lead sulphate salts that form can be broken down.   This state of equilibria maintains the life of the battery. However, if a battery remains on the shelf for a long period of time or sits in an unused car, lead sulphate forms without being broken down.”

“In the build-up of lead sulphate, a white salt layer develops inside the battery and settles around the battery’s active material, blocking the pores of the separators. This restricts the flow of electrons, and in the worst case scenario, cuts the circuit off completely as the current cannot flow,” explains Barnabas. “As more and more reaction surface becomes sulphated, there would be increased resistance in the battery, resulting in overheating.” 

Sulphation is most common in lead acid batteries.  However, Barnabas says that a sulphation problem can be easily identified.  “An indication of sulphation is a whiteness in the eye of the battery.   For a healthy battery fitted with a magic eye, this should be green.”  As most automotive dealers will know, a green eye signifies a healthy, charged battery.  A black eye indicates less than 65% charged.  Barnabas adds a cautionary note, “Although a black battery eye might indicate that the battery is not fully charged, this doesn’t mean there is sulphation.  You need to look for the whiteness around the eye, regardless of colour.”

The good news for consumers is that sulphation can be easily overcome.  Barnabas says that when a vehicle is not being used for a period of time, the engine should nonetheless be started frequently. “Let the engine run for approximately 15 minutes to allow any sulphate salts that are being formed to break down. Do this once a week.  Alternatively, it is useful to take a short drive, which helps keep everything in good working order.” 

For retailers, the best option is to have chargers on site and to charge the batteries at least once every month, maximum two months, to ensure the integrity of the battery is maintained.  Barnabas adds that for those retailers with no chargers, a rotation agreement can be arranged with Probe, so that your stock can be charged and returned in good condition.  He concludes, “There is no reason to invest in good batteries, only for them to lose value and exceed the warranty replacement time period without being used.”