Amazon, the Amazon logo, AmazonSupply, and the AmazonSupply logo are trademarks of Amazon.com, Inc. or its affiliates.  In 1992 about 3 million tons of lead were used in the manufacture of batteries. The active materials change physical form during charge/discharge, resulting in growth and distortion of the electrodes, and shedding of electrode into the electrolyte.  There are commercial products claiming to achieve desulfation through various techniques such as pulse charging, but there are no peer-reviewed publications verifying their claims.
An effective separator must possess a number of mechanical properties; such as permeability, porosity, pore size distribution, specific surface area, mechanical design and strength, electrical resistance, ionic conductivity, and chemical compatibility with the electrolyte. It is believed that large crystals physically block the electrolyte from entering the pores of the plates. This is one of the reasons a conventional car battery can be ruined by leaving it stored for a long period and then used and recharged. Traction (propulsion) batteries are used in golf carts and other battery electric vehicles. This solution can then react with the lead and other metals in the battery connector and cause corrosion. Rubber separators are stable in battery acid and provide valuable electrochemical advantages that other materials cannot.
Thus, not all the lead is returned to the battery plates, and the amount of usable active material necessary for electricity generation declines over time.
EDTA can be used to dissolve the sulfate deposits of heavily discharged plates. VRLA (valve-regulated lead–acid) batteries, Learn how and when to remove this template message, automobile starting, lighting, and ignition, commercial products claiming to achieve desulfation, "Lead batteries for utility energy storage: A review", "All About Batteries, Part 3: Lead–acid Batteries", "How Batteries Store and Release Energy: Explaining Basic Electrochemistry", "Focus: Relativity Powers Your Car Battery", "Liquid Tin Bismuth Battery for Grid-Scale Energy Storage", http://www.windsun.com/Batteries/Battery_FAQ.htm#Battery%20Voltages, "Handbook for stationary lead–acid batteries (part 1: basics, design, operation modes and applications), page 65", "Recommended voltage settings for 3 phase charging of flooded lead acid batteries.
A VRLA cell normally recombines any hydrogen and oxygen produced inside the cell, but malfunction or overheating may cause gas to build up. This converts the formerly liquid interior of the cells into a semi-stiff paste, providing many of the same advantages of the AGM. While lead recycling is a well-established industry, more than 40,000 metric tons (39,000 long tons; 44,000 short tons) ends up in landfills every year. Some batteries are designed as a compromise between starter (high-current) and deep cycle. If you overcharge an AGM battery there is a distinct possibility that you will damage the battery to the point that it does not function.  The auto industry uses over 1,000,000 metric tons (980,000 long tons; 1,100,000 short tons) of lead every year, with 90% going to conventional lead–acid vehicle batteries. VRLA cells do require maintenance. Leakage is minimal, although some electrolyte still escapes if the recombination cannot keep up with gas evolution. Starting batteries kept on a continuous float charge will suffer corrosion of the electrodes which will also result in premature failure. In this case the battery voltage might rise to a value near that of the charger voltage; this causes the charging current to decrease significantly. If this happens (for example, on overcharging) the valve vents the gas and normalizes the pressure, producing a characteristic acid smell.  For example, there are approximately 8.7 kg (19 lb) of lead in a typical 14.5-kg (32 lb) battery. Large lead–acid batteries are also used to power the electric motors in diesel-electric (conventional) submarines when submerged, and are used as emergency power on nuclear submarines as well. This allows loose disintegrated material to fall off the plates and collect at the bottom of the cell, prolonging the service life of the battery. In a valve regulated lead–acid (VRLA) battery, the hydrogen and oxygen produced in the cells largely recombine into water.
Portable batteries for miners' cap lamps headlamps typically have two or three cells.. The standard battery charger uses technology that was designed to charge the lead acid batteries. Personnel working near batteries at risk for explosion should protect their eyes and exposed skin from burns due to spraying acid and fire by wearing a face shield, overalls, and gloves.
VRLA types became popular on motorcycles around 1983, because the acid electrolyte is absorbed into the separator, so it cannot spill. Wood was the original choice, but it deteriorates in the acid electrolyte.