For nearly a century, the car battery served a simple purpose: it stored electrical power to power the ignition system, the lights, and, on occasion, the starter Battery size (The Battery Local authority International assigns statistics and notes to each battery size of the group, referring to the battery size that best fits the physical size as well as port arrangement, for a particular vehicle wrapping) and stored energy were all that was required to effectively pick the proper battery.
This battery selection process became more complicated with the introduction of Micro Hybrid Electric (also known as Start-Stop) Vehicles.
While traditional car batteries were covered in a previous article, we’ll take a closer look at batteries used in stop-start vehicles before providing some general advice on selecting the best battery for the application.
What distinguishes the Stop-Start battery?
Stop-Start battery reduces exhaust gas emissions and fuel consumption by turning off the engine when the vehicle comes to a complete stop. However, vehicles equipped with Start-Stop systems place a greater strain on the battery.
Unlike in conventional vehicles, where the battery only needs to provide a large current to turn the starter motor at the start of a trip, the Start-Stop battery must deal with numerous discharges and recharge cycles during a city drive. Furthermore, even when the engine is turned off, the battery must power ancillary systems like lights, air conditioning, and in-car entertainment.
In contrast to traditional vehicles, where the battery only needs to provide a large current to turn the starter motor at the start of a trip, the Start-Stop battery must deal with numerous discharges and recharge cycles during a city drive.
Furthermore, even when the engine is turned off, the battery must continue to power ancillary systems such as lights, air conditioning, and in-car entertainment.
As discussed in the article “Car Battery Life and Maintenance,” the Lead Acid Battery operates within a relatively narrow State of Charge window in which, if the battery is discharged below its design limits or deep-cycled, sulfation accelerates, reducing the battery’s ability to accept a charge and resulting in a shorter lifecycle.
To meet these demands, manufacturers have created technologies that ensure cyclability and deep-draw while also ensuring durability.
Stop-Start Battery Types:
Battery suppliers, always mindful of the delicate balance between cost and performance, offer consumers two basic types of stop-start technologies:
ECM/AFB Battery for entry-level start-stop vehicles ECM (Enhanced Cyclic Mat), also known as Advanced Flooded Battery (AFB), was designed to provide increased performance, longer battery life, and the ability to handle additional cyclic demands at a lower cost than AGM (Absorbent Glass Mat) batteries.
Cyclability is significantly improved by increasing the electrolyte reservoir, while advancements in the construction of negative grids, which typically incorporate an alloy of Lead, Calcium, and Tin, result in a longer service life and lower water loss. The expander blend has also been modified to accommodate the increased number of cycles. Furthermore, the battery’s performance is optimized for the most demanding applications by incorporating a double layer separation.
AGM batteries are specifically designed for larger, more sophisticated stop-start vehicles that use additional energy-saving systems to reduce fuel consumption, such as brake regeneration and energy management. AGM batteries are also slightly more expensive!
The AGM, on the other hand, can charge up to five times faster than the standard flooded version and can deep cycle, with a depth-of-discharge of 80 percent, compared to the flooded, which is specified at 50 percent to achieve the same cycle life. AGM batteries have a very low internal resistance, can deliver high currents, and have an acceptable service life even when deep cycled. The technology requires no maintenance, is extremely reliable, and is lighter than flooded lead acid equivalents. These batteries also perform well in cold temperatures and have a low self-discharge rate.