BY ALLEN L PHILLIPS
The lead acid battery has been a common component of cars since the introduction of starter motors early in the last century. Early batteries were 6 volts with most manufacturers switching to 12 volt batteries in the 1950’s as electrical systems became more demanding (think radios).
Since that time there has been occasional speculation about changing to 18 or 24 volt systems as manufacturers contemplated the potential electrical demands of future cars. But today, cars are still being built with 12 volt systems using the tried and true lead acid batteries.
Lead acid batteries contain a series of lead plates suspended in acid, hence the name “lead acid battery”. An obvious and common problem with these batteries is leakage, usually around the battery posts, which can corrode the battery terminals leading to a reduction in available electrical power to start the car.
Additionally, the power demands of newer cars with GPS, backup cameras, heated seats, etc. has caused car makers to require larger batteries which are heavier and take up more space at a time when manufacturers are trying to minimize weight in order to meet government mandated fuel consumption standards.
Absorbent Glass Mat (AGM) batteries were developed in the 1980’s for military applications and are now finding their way into higher end cars. While AGM batteries go a long way toward solving the problems, they still have lead plates suspended in acid. The difference is that the plates are separated by absorbent fiberglass mats. This allows more plates in the same space because they can be closer together, separated by the glass mats, increasing efficiency and virtually eliminating the possibility of internal failure that results when the plates touch each other.
The result is a safer, more powerful battery, much less prone to leaks. They work better to power the features that people now want in their cars and they last longer. As you might expect, they are also more expensive.
But, while the typical lead acid battery lasts from 3 to 5 years, AGM batteries last 5 to 7 years. If your car is equipped with the AGM battery, replacing it when needed with the proper battery is well worth the extra cost. It is expected that 50% of all new vehicles will include AGM batteries by 2023, 5 years from now.