Compared with flooded lead-acid cells, VRLA batteries offer several advantages. The battery can be mounted in any position, since the valves only operate on over pressure faults. Since the battery system is designed to be recombinant and eliminate the emission of gases on overcharge, room ventilation requirements are reduced and no acid fume is emitted during normal operation. The volume of free electrolyte that could be released on damage to the case or venting is very small. There is no need (nor possibility) to check the level of electrolyte or to top up water lost due to electrolysis, reducing inspection and maintenance.
Absorbent glass mat (AGM) is a class of VRLA battery in which the electrolyte is absorbed into a mat of fine glass fibers. The plates in an AGM battery may be flat like a wet cell lead-acid battery in a rectangular case. In cylindrical AGMs, the plates are thin and wound, like most consumer disposable and rechargeable cells, into spirals so they are also sometimes referred to as spiral wound. Their unique (for lead-acid chemistries) construction also allows for the lead in their plates to be purer as they no longer need to support their own weight as in traditional cells. Their internal resistance is lower than traditional cells due to plate proximity and the pure lead plates have lower resistivity, they handle higher temperatures better, and self-discharge more slowly.Their specific power is very good and they can be charged and discharged quite rapidly, however their specific energy tends to be lower than traditional flooded batteries. They are often used in high performance electric vehicles due to their high power density
(adsbygoogle = window.adsbygoogle || ).push();
Many modern motorcycles on the market utilize AGM or factory-sealed AGM batteries for the combined benefits of reduced likelihood of acid spilling during accidents, and for packaging reasons (lighter, smaller battery to do the same job; the battery can be installed at an odd angle if needed for the design of the motorcycle).Due to the higher manufacturing costs compared with flooded lead-acid batteries, AGM technology is currently being used on premium vehicles. As vehicles become heavier and equipped with greater electronic devices such as navigation, stability control, and premium stereos, AGM batteries are being employed to lower vehicle weight and provide better electrical reliability compared with flooded lead-acid batteries.
A VRLA-AGM battery uses recombinant technology. The oxygen produced from the positive plates of the battery is absorbed by the negative plates. This suppresses the generation of hydrogen at the negative plates. The recombination of oxygen and hydrogen leads to water, retaining the electrolyte amount within the battery. Water filling is never required. Battery should never be opened as this would damage the battery with additional oxygen from the air. The warranty will be void if the battery is opened.