is a three-stage charging procedure for lead–acid batteries. A lead–acid battery's nominal voltage is 2.1 V for each cell. For a single cell, the voltage can range from 1.8 V loaded at full discharge, to 2.10 V in an open circuit at full charge. varies depending on battery type (flooded cells, gelled electrolyte, ), and ranges from 1.8 V to 2.27 V. Equali. is a three-stage charging procedure for lead–acid batteries. A lead–acid battery's nominal voltage is 2.1 V for each cell. For a single cell, the voltage can range from 1.8 V loaded at full discharge, to 2.10 V in an open circuit at full charge. varies depending on battery type (flooded cells, gelled electrolyte, ), and ranges from 1.8 V to 2.27 V. Equalization voltage, and charging voltage for sulfated cells, can range from 2.67 V to almost 3 V (only until a charge current is flowing). Specific values for a given battery depend on the design and manufacturer recommendations, and are usually given at a baseline temperature of 20 °C (68 °F), requiring adjustment for ambient conditions. IEEE Standard 485-2020 (first published in 1997) is the industry's recommended practice for sizing lead–acid batteries in stationary applications. The lead–acid battery is a type of. First invented in 1859 by French physicist, it was the first type of rechargeable battery ever created. Compared to the more modern rechargeable batteries, lead–acid batteries have relatively low and heavier weight. Despite this, they are able to supply high. These features, along with their low cost, make them useful for in order to provide the high current required by. Lead–acid batteries suffer from relatively short cycle lifespan (usually less than 500 deep cycles) and overall lifespan (due to the double sulfation in the discharged state), as well as long charging times; an average takes anywhere between 6 to 12 hours to fully charge from a discharged state. As they are not as expensive when compared to newer technologies, lead–acid batteries are widely used even when surge current is not important and other designs could provide higher energy densities. In 1999, lead–acid battery sales accounted for 40–50% of the value from batteries sold worldwide (excluding China and Russia), equivalent to a manufacturing market value of about US$15. Large-format lead–acid designs are widely used for storage in backup power supplies in telecommunications networks such as for, high-availability as used in hospitals, and. For these roles, modified versions of the standard cell may be used to improve storage times and reduce maintenance requirements. Gel cell and absorbed glass mat batteries are common in these roles, collectively known as. When charged, the battery's chemical energy is stored in the potential difference between metallic at the negative side and on the positive side. The French scientist Nicolas Gautherot observed in 1801 that wires that had been used for electrolysis experiments would themselves provide a small amount of secondary current after the main battery had been disconnected. In 1859, 's lead–acid battery was the first battery that could be recharged by passing a reverse current through it. Planté's first model consisted of two lead sheets separated by rubber strips and rolled into a spiral and immersed in a solution containing about 10 percent sulfuric acid. His batteries were first used to power the lights in train carriages while stopped at a station. In 1881, invented an improved version that consisted of a lead grid lattice into which a lead oxide paste was pressed, forming a plate. This design was easier to mass-produce. An early manufacturer (from 1886) of lead–acid batteries was. Using a gel electrolyte instead of a liquid allows the battery to be used in different positions without leaking. Gel electrolyte batteries for any position were first used in the late 1920s, and in the 1930s, portable suitcase radio sets allowed the cell to be mounted vertically or horizontally (but not inverted) due to valve design. In the 1970s, the valve-regulated lead–acid (VRLA), or sealed, battery was developed, including modern absorbed glass mat (AGM) types, allowing operation in any position. It was discovered early in 2011 that lead–acid batteries do in fact use some aspects of relativity to function, and to a lesser degree, liquid metal and such as the Ca-Sb and Sn-Bi also use this effect. In the discharged state, both the positive and negative plates become (PbSO 4), and the loses much of its dissolved and becomes primarily water. Negative plate reaction Pb(s) + HSO 4(aq) → PbSO 4(s) + H (aq) + 2e The release of two conduction electrons gives the lead electrode a negative charge. As electrons accumulate, they create an electric field that attracts hydrogen ions and repels sulfate ions, leading to a double layer near the surface. The hydrogen ions screen the charged electrode from the solution, which limits further reaction unless charge is allowed to flow out of the electrode. Positive plate reaction PbO 2(s) + HSO 4(aq) + 3H (aq) + 2e → PbSO 4(s) + 2H 2O(l)taking advantage of the metallic conductivity of. The total reaction can be written asPb(s) + PbO 2(s) + 2H 2SO 4(aq) → 2PbSO 4(s) + 2H 2O(l) The net energy released per (207 g) of Pb(s) converted to PbSO 4(s) is approximately 400 kJ, corresponding to the formation of 36 g of water. The sum of the molecular masses of the reactants is 642.6 g/mole, so theoretically a cell can produce two of charge (192,971 ) from 642.6 g of reactants, or 83.4 per kilogram for a 2-volt cell (or 13.9 ampere-hours per kilogram for a 12-volt battery). This comes to 167 per kilogram of reactants, but in practice, a lead–acid cell gives only 30–40 watt-hours per kilogram of battery, due to the mass of the water and other constituent part. Another form for discharging reaction: Negative plate: Pb(s) + H2SO4(aq) → PbSO4 + H2 + 2e Positive plate: PbO2(s) + H2SO4 + H2 + 2e → PbSO4(s) + 2H2O In the fully charged state, the negative plate consists of lead and the positive plate is. The electrolyte solution has a higher concentration of aqueous sulfuric acid, which stores most of the chemical energy. with high charging generates and gas by, which bubbles out and is lost. The design of some types of lead–acid battery (e.g., "flooded", but not ) allows the electrolyte level to be inspected and topped up with pure water to replace an. Because the electrolyte takes part in the charge-discharge reaction, this battery has one major advantage over other chemistries: it is relatively simple to determine the state of charge by merely measuring the of the electrolyte; the specific gravity falls as the battery discharges. Some battery designs include a simple using colored floating balls of differing. When used in diesel-electric, the specific gravity was regularly measured and written on a blackboard in the control room to indicate how much longer the boat could remain submerged. The battery's open-circuit voltage can also be used to gauge the state of charge. If the connections to the individual cells are accessible, then the state of charge of each cell can be determined which can provide a guide as to the state of health of the battery as a whole; otherwise, the overall battery voltage may be assessed.
