What is the state of charge of lead acid battery?
The charge-discharge reaction process of lead-acid batteries can be seen: After charging, the sulfuric acid content in the electrolyte increases, and the density increases; in the discharged electrolyte, because part of the sulfuric acid forms the compound PbSO4 in solid form, it is transferred to Among the plates, the sulfuric acid in the electrolyte is reduced. This reduction has a strict quantitative relationship: for every 2 electrons flowing in the external circuit, 2 molecules of sulfuric acid must be consumed. This provides a possibility. In the process of discharging, the decrease in the density of the sulfuric acid electrolyte is used to determine how much electricity the battery discharges; on the contrary, during the charging process, the increase in the density of the electrolyte can also be used to determine the battery has been charged. The amount of effective power input.
In many cases, the process stipulates that the method of measuring the density of the electrolyte is used to judge the state of charge of the lead-acid battery. The theoretical basis is the above.
In large-capacity fixed batteries, a density meter is usually installed. Plastic balls of different densities are installed in small compartments according to the density. As the degree of charge and discharge changes, the density of the electrolyte changes accordingly. The plastic pellets will move up and down. According to the numerical value on the board, the density of the electrolyte can be easily known, and the state of charge of the battery can be judged from the density.
On the side of some batteries, there are three colored balls with different densities: red, yellow, and green. The ups and downs respectively indicate the three states of charge: “should be charged”, “usable”, and “full charge”.
Ordinary suction tube buoy density meter can also play the same role. Obviously, the above measurement and judgment must be correct under the premise that the original electro-liquid density value in the battery is known, the total acid content in the battery is unchanged, the electrolyte density is uniform up and down, and the electrode plates are not broken and de-powdered. These conditions, the battery does not exist since the beginning of use, and the deviation of various parameters from the original is getting larger and larger, so the accuracy of this detection method is getting lower and lower. When using this detection method to obtain technical data, pay attention to this effect.
What is the lower limit standard of lead acid battery discharge?You can also learn more about lead acid battery.