Design and qualities of VARTA^® ProMotive AGM truck batteries

The AGM truck battery is the result of many years of expertise gained by VARTA^® in the production of start-stop batteries. Our plants in Germany have supplied vehicle manufacturers and workshops around the world with more than 70 million AGM batteries since production began in 2003. The abbreviation AGM stands for Absorbent Glass Mat which refers to the glass fleece separator binding the acid and at the same time separates the positive and negative plates.

A unique feature of the VARTA^® AGM battery is the PowerFrame® design. The VARTA^® ProMotive AGM battery uses the PowerFrame grid for the first time on both the positive and negative plates. The PowerFrame grid design is optimised for maximum performance and ensures excellent starting characteristics even with low charge levels. AGM technology is associated with an elaborate and technically sophisticated production process. When manufacturing conventional wet batteries, the battery acid is filled through openings in the cover at the end of the production process. This would not work with a Truck AGM battery. A special method is required here in order to insert the electrolyte into the glass fleece separators. This is achieved by generating a vacuum in the battery case, which then draws the acid into the separators and ensures optimum and even distribution.

Compression within the cells is another important factor concerning AGM batteries. The plates and separators must be pressed together with the correct pressure. This pressure must be neither too high nor too low in order for the battery to achieve optimum performance. A reinforced battery case has been developed to ensure uniform compression over the battery’s lifetime. This is used exclusively for VARTA^® Truck AGM batteries.

Even non-specialists can see the high compression in the cells from the curved walls of the casing. This curvature is normal and indicates the correct function of the battery cells. Another special feature of AGM technology: Each cell is a closed system. This means that each individual cell is closed with a separate valve, which safely releases the gas generated during charging via a central degassing system with ignition protection. If there is no excess pressure the valve seals the cell completely so that no oxygen can enter the cell from the outside. This is important because the plates are not surrounded by free acid. Without a valve, oxygen could come into contact with the plates, which would result in the cells discharging and premature failure. This system of closed cells is unique to AGM and contributes to the high performance and reliability of AGM Truck batteries.