Sorry bit sla is not agm. sla is sealed lead acid or maintenance free. It is still a standard lead acid though.
Agm batteries stand for Absorbed Glass Mat.
Absorbed glass mat (AGM) is a class of VRLA battery in which the electrolyte is held on the glass mat separator by way of capillary action.
[edit] History
AGM batteries were developed by Concorde Aircraft Battery, in the late 1980s in San Bernardino California. The AGM battery technology was developed to be a warm weather, vibration resistant, and chemical alternative to the expensive Ni-Cad batteries in both naval helicopters and fighter aircraft. As production was mechanized, Optima Battery patented a spiral wound method for producing an AGM battery. Due to the spiral wound cell configuration, they are also sometimes referred to as spiral wound. These two manufacturers maintain UL, CE, and Mil-Spec ratings on their batteries.
[edit] Manufacture
AGM batteries are just like flooded lead acid batteries, except the electrolyte is being 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 comprise the fine glass fibers glass mat do not absorb nor are affected by the acidic electrolyte they reside in. These mats are wrung out 2-5% after being soaked in acids, prior to manufacture completion and sealing. The AGM battery can now accumulate more acid than is available, and never spill a drop.
The plates in an AGM battery may be any shape. Some are flat, others are bent or wound. AGM batteries, both deep cycle and starting, are built in a rectangular case to BCI battery code specifications. Optima Battery builds a patented cylindrical AGM series of batteries that are fashioned to fit the same BCI battery size specifications as any other battery.
[edit] Advantages
All AGM batteries boast some significant performance enhancement over traditional flooded lead acid cells:
* AGM construction allows purer lead in the plates as each plate no longer needs to support its own weight based on the sandwich construction with AGM matting. Traditional cells must support their own weight in the bath of acid.
* un-spillable
* high specific power or power density, holding roughly 1.5x the AH capacity as flooded batteries based on purer lead[citation needed]
* low internal resistance allowing them to be charged and discharged quite rapidly
* never requiring addition of water
* acid is encapsulated in the matting
* will operate well below 0°F or -18 °C.
* UL, DOT, CE, Coast Guard, and Mil-Spec approved types
* vibration resistant based on the sandwich construction.
[edit] Disadvantages
* Cost. AGM automobile batteries for example, are typically about twice the price of flooded-cell batteries in a given BCI size group.
* AGM batteries have up to a 10 year lifespan, but must be sized to discharge less deeply than the traditional flooded batteries. For an AGM battery, the depth of discharge for optimal performance is 50% but flooded batteries can be rated up to 80% depth of discharge.
* AGM batteries do not tolerate overcharging. Overcharging dissociates the water in the electrolyte, which is unable to be replaced, leading to premature failure.
So while both battery types are grouped into the same classification, they are actually different and thus do perform differently.
