The most common type of lead acid battery - VRLA battery

If you are not familiar with lead acid battery, I think you never heard of VRLA battery that is the most common type. VRLA battery is short for valve-regulated lead acid battery. They always include a safety pressure relief valve, so they don't require regular addition of distilled water to the cells. As opposed to flooded lead acid batteries, a VRLA can not spill its electrolyte if it is inverted. In fact, "valve regulated" doesn't wholly describe the technology. The oxygen evolved at the positive plates will largely recombine with the hydrogen ready to evolve on the negative plates, creating water and so preventing water loss. The valve is a safety feature in case of hydrogen evolution becomes dangerously high.

VRLA batteries are commonly further classified as AGM VRLA battery and gel battery. The electrolyte of AGM batteries 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 compose the fine 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.

However, gel battery uses a gelified electrolyte. The sulfuric acid is mixed with silica fume, which makes the resulting mass gel-like and immobile. Gel batteries reduce the electrolyte evaporation, spillage (and subsequent corrosion issues) common to the wet-cell battery, and boast greater resistance to extreme temperatures, shock, and vibration. With gel electrolyte the separator was no longer such a critical, hard to make component. And cycle life was increased in some cases dramatically. With gel electrolyte a number of the shedding of active material failure problems were eliminated. More importantly real gas recombination was used to make batteries that were not "watered" and could be called maintenance free.

Most lead acid batteries are VRLA battery. So we just don't know this name. As a matter of fact, we are using these batteries. Do you want to know more useful information about VRLA battery? How should we maintain these batteries? What should we pay attention to when we charge them? How to extend its life? These questions all are very important for its life. To prolong its life, we should learn more knowledge to help us. Just go on reading my blog, and you will get what you want.