AGM technology became popular in the early 1980s as a sealed lead acid battery for military aircraft,
vehicles and UPS to reduce weight and improve reliability. The sulfuric acid is absorbed by a very fine
fiberglass mat, making the battery spill-proof.Battery Types This enables shipment without hazardous material restrictions.
The plates can be made flat to resemble a
AGM has very low internal resistance, is capable to deliver high currents on demand and offers a relatively long service life, even when deep cycled. AGM is maintenance free, provides good electrical reliability and is lighter than the flooded lead acid type. While regular lead acid batteries need a topping charge every six months to prevent
the buildup of sulfation, AGM batteries are less prone to
sulfation and can sit in storage for longer before a charge becomes necessary. The battery stands up well to low temperatures and has a low self-discharge.
The leading advantages of AGM are a
charge that is up to five times faster than the flooded version, and the ability to deep cycle. AGM offers a depth-of-discharge of 80 percent; the flooded, on the other hand, is specified at 50 percent DoD to attain the same cycle life.
OEM is “original equipment manufacturer”
which means the battery is identical to
what was originally supplied with the phone. Non-OEM is a
battery made by a different company that reverse-engineered the original battery and started producing
functionally-equivalent copies for sale into the same application.
Battery Types There is no hard and fast rule, but generally people perceive OEM to be higher quality and more reliable than non-OEM, as a result pricing will often be higher for OEM batteries.
Batteries are difficult to manufacture consistently because minor variations in water content (parts per million) and minor mis-matching of the anode and cathode capacities (produced by micron thickness
variations in coating processes) cause substantial cycle life reduction in the final battery. It could be the difference between getting 100 cycles out of a battery (not to hard) versus 500 (more challenging).
OEM’s might have a higher reject rate of marginal batteries,
which leads to higher costs on the ones that do pass.