1. Absorbent glass mat (AGM)

AGM batteries differ from flooded lead acid batteries in that the electrolyte is held in the glass mats, as opposed to freely flooding the plates. Very thin glass fibers are woven into a mat to increase surface area enough to hold sufficient electrolyte on the cells for their lifetime. The fibers that compose the fine glass mat do not absorb nor are they affected by the acidic electrolyte. These mats are wrung out 2–5% after being soaked in acids, prior to manufacture completion and sealing.

The plates in an AGM battery may be any shape. Some are flat, others are bent or rolled. AGM batteries, both deep cycle and starting, are built in a rectangular case to Battery Council International (BCI) battery code specifications.

AGM batteries present better self discharging characteristics than conventional batteries in different range of temperatures.

As with lead-acid batteries to maximize the life of AGM battery is important to follow charging specifications and a voltage regulated charger is recommended. And also there is a correlation between the depth of discharge (DOD) and the Cycle life of the battery, with differences between 500 and 1300 cycles depending on depth of discharge