Absorbed Glass Mat batteries are constructed differently than the traditional flooded battery.

In agm marine battery (also called starved electrolyte), there is a thin ultra-fine fiberglass mat sandwiched between the plates that are saturated with battery acid to about 95% of what they can hold. This mat is then packed in between the plates and slightly compressed, then welded/soldered in place. Because the plates and mats are packed fairly tight, they are almost immune to vibration.

AGM (Absorbed Glass Mat) sealed battery technology was originally invented in 1980, and developed and introduced in 1985 for military aircraft where power, weight, safety, and reliability were paramount considerations. The Concorde AGM batteries are VRSLAB (Valve Regulated Sealed Lead-Acid Battery), sometimes referred to as VRLA (Valve Regulated Lead-Acid). Several manufacturers now produce AGM batteries, but Concorde was the first to develop the technology for commercial non-military use.

AGM Batteries Are Not Gelled Batteries:
Concorde AGM batteries are NOT a gelled electrolyte. It is considered a "Recombinant Gas Absorbed Electrolyte" battery. This cuts water loss by up to 98%. Loss of charge due to self-discharge is 3 to 10 times better than with conventional gelled, and 5 to 50 times less than traditional flooded batteries. The gasses recombine almost 100% within the battery, reducing Hydrogen emissions to a level far below most battery types, and less than half of the lower explosive limit for Hydrogen. In addition, they do not have the charge and discharge current limitations that most gelled batteries have.

Concorde AGM battery technology has continued to develop and offer improvements over other sealed battery technologies. AGM technology has become the next step in the evolution of both starting and deep cycle sealed batteries for marine, RV, and aviation applications. These are the same batteries that the US Military uses in many of it's armored and standard vehicles. This "next generation" technology delivers increased safety, performance, and service life over all other existing sealed battery types, including gel technology. All Concorde AGM batteries carry a one-year full warranty - most gelled cells carry only a 90-day warranty.

AGM batteries have much better resistance to vibration and shock due to their construction than most flooded batteries. The plates are packed in with the glass mat, reducing plate movement and vibration to nearly zero. In addition, because the glass mats are not totally saturated and the liquid does not expand to cause plate and case damage, AGM batteries can withstand freezing - you will get little or no output from a frozen battery, but at least it will not ruin the battery or break the case.

Concorde AGM batteries meet MIL-SPEC B8565J and FAR 23.1353, 25.1353(c), 27.1353, 29.1353(3), 25.853(a). All Concorde AGM batteries are shippable without restriction by any means of transportation, including air. Hazardous labeling is not required.