As the world of automotive batteries continues to expand and vehicle manufacturers start looking for alternatives to standard flooded acid batteries, a shop owner or tech needs to be prepared to service any size or type battery that comes into their shop environment. One of the battery types becoming more prevalent in passenger vehicles is the AGM battery. While AGM batteries have benefits over other types, there are precautions and guidelines that a shop must take to properly service these batteries. In this article, we’ll cover a few shop equipment categories to help ensure your shop is prepared to service AGM batteries.
What is an AGM Battery?
AGM (absorbed glass mat) batteries differ from flooded acid batteries in the sense that the electrolyte is absorbed into thin fiberglass mat separators, rather than flooding all the plates. These very thin glass fibers are designed to increase the surface area enough to hold sufficient electrolyte on the cells for their lifetime. This results in a more dependable and resilient battery that is better suited to the constant cycling resulting from the electronic conveniences and add-ons found in modern passenger vehicles.
AGM batteries can be found in a variety of shapes and sizes, including spiral-wound designs or in traditional designs resembling a flooded lead-acid battery. These batteries’ prices typically run 50-100% higher than flooded acid batteries, so they are commonly found in higher end vehicles or in applications where their durability, cycling capacity and vibration resistance are of great value. With the increasing demand on a battery to power amenities such as DVD players, navigations systems, and power controls, the amount of AGM batteries found in passenger vehicles is predicted to increase in the coming years.
AGM batteries require a “smart” charging routine, by a Smart Battery Charger, in order to be properly charged. In this case, “smart” means progressing through the charging stages in a manner compatible with the specific battery being charged (AGM) and automatically and precisely adjusting its output to achieve a full, beneficial charge. Charging an AGM battery with a traditional battery charger will result in too much energy being pushed into the battery, with a lack of the control needed to charge it correctly. This could easily damage the battery, reducing its reserve capacity and shortening its service life.
But, how do you know if it is worth your time and effort to charge a problem battery rather than replacing it? The right tool for that assessment is your battery tester. But, do AGM batteries present any specific challenges in this regard? Not if you have the right equipment.
The most important thing to consider or determine is whether your battery tester is specifically designed to test a wide variety of battery, including AGM batteries. For digital testers, your tester should prompt you to indicate the type of battery construction you are testing, such as SLI, AGM or Gel Cell. If not, your tester may only be capable of properly assessing traditional flooded batteries. A digital tester is only as good as the reference data within the tester itself. So, you want to be sure that you are referencing data specific to the battery you are testing. And, since digital testers can accurate assess discharged batteries.
As familiarity with and knowledge of AGM batteries grows, we have been fielding a new question that we haven’t heard before from shop owners and technicians:
“OK, I now know that I need to use a special charger with AGM batteries, but what about my jump starter? Does that need to be AGM-compatible as well in order to avoid damage to these new batteries?
A jump starter is designed to act as an extension of the vehicle’s battery, enabling that sudden burst of energy that makes the engine starting process possible when the vehicle’s battery is not up to the task itself. While powerful, this auxiliary supply of energy does not affect the health or well being of the vehicle’s battery, whether it is a flooded, AGM Gel Cell or other type of battery.
Be Prepared with the Right Tools We hope that this quick survey of the tools needed to properly service and maintain AGM batteries is helpful to you. With the right equipment, particularly in the battery charger arena, extending your service range into these increasingly popular new batteries should be profitable and painless.