AGM Batteries

AGM batteries are versatile, have high performance and are designed for high demands. In principle, the structure of an AGM battery is the same as that of a wet cell battery. However, in an AGM, the electrolyte is no longer free-floating, but rather is bound in a special glass fiber separator – hence the name “Absorbent Glass Mat”. The large contact area contributes to the power output and makes the battery leak-proof. Even if the battery case is fractured, no battery acid can escape.

Due to its construction, the battery is sealed airtight. This feature enables internal recombination of oxygen and hydrogen so that there is minimal water loss. To protect against excess pressure, the individual battery cells are equipped with a safety valve so that they remain safe, even in case of a fault.

With regard to their service life, AGM batteries have significant advantages over simple starter batteries. An AGM battery can withstand three times more cycle life than a conventional starter battery.

AGM batteries are ideal for vehicles with automatic start-stop systems with braking energy recovery (recuperation), as a conventional starter battery cannot handle the high power demands of these systems. AGM batteries are also the right choice for cars with high-energy consumption and a large number of electrical consumers.

Cars with an advanced automatic start-stop system are equipped with an AGM battery. Only an AGM battery may be used as a replacement.

With braking energy recovery (recuperation), the energy that results from braking is not completely lost. Part of the energy, which is recovered from the braking process, is fed into the battery of the vehicle. AGM batteries provide the technology that is suitable for recuperation.

A conventional wet battery (SLI) only starts the engine once per journey. The optimum 100% charge of an SLI only reduces once when starting and is then recharged by the alternator during the journe.

With an automatic start-stop system, the battery has to start the engine several times during the journey. The charge level of the battery therefore falls several times, and electrical consumers still need to be supplied with power during the standstill period.

This puts an especially large load on the battery. During driving, the battery is recharged, just like a conventional starter battery. However, due to the recovery of braking energy, additional charge capacity must be available in order to be able to feed in the regenerative braking energy. AGM batteries are therefore operated in the partial charge range, and only attain a full 100% charge during recuperation. In the subsequent stop phase, the charge is reduced due to the supply of electrical consumers so that there is once again sufficient “room” available to store the energy from the next braking phase.