Absorbed Glass Mat (AGM) batteries are sometimes referred to as sealed lead acid, but that is not correct and in fact they have a low-pressure relief valve and should be considered as valve-regulated lead-acid. That valve can open during charging when the battery reaches the gassing point or close to full charge to prevent overpressure inside the container. They can therefore release some amount of gas during operation, which contains hydrogen, oxygen, and small amounts of sulphuric acid. This has to be taken into account in the installation for ventilation and must never be installed inside a closed or sealed box. VRLA-AGM should not be confused with VRLA-GEL which has a very different internal construction. That said, there are some manufacturers, such as our supplier; that have come up with an optional process to fill AGM batteries with a chemically-produced GEL so as to provide better heat dissipation, life and cycling ability in an AGM battery.
Advanced Battery Systems has been supplying VRLA-AGM batteries since 1988 so we have a lot of experience and knowledge with this type. We have invested considerable time and effort in finding the right supplier for our ABS brand AGM batteries that can provide the quality and reliability that we have come to expect. Our ABS brand AGM batteries are 100% discharge tested before shipping from the factory using the latest automated equipment. This has allowed us to become an industry leader in this product.