Which instrument should be used to measure the state of charge of a lead-acid storage battery?

Which instrument should be used to measure the state of charge of a lead-acid storage battery?

• A. Hydrometer
• B. Hygrometer
• C. Voltmeter
• D. Multimeter

Answer: (A)

The hydrometer is specifically designed to measure the density of the electrolyte solution in a lead-acid storage battery. This density is directly related to the state of charge of the battery. As the battery discharges, the density of the electrolyte decreases, while it increases as the battery is charged. By comparing the specific gravity readings obtained from the hydrometer to standard values, one can accurately assess the state of charge of the battery. While the voltmeter and multimeter can provide insights into the battery's voltage, they do not directly quantify the battery's charge state in terms of electrolyte composition. A hygrometer, which measures humidity, is not relevant in this context. Therefore, the hydrometer is the most appropriate instrument for determining the charge state of lead-acid batteries.

The hydrometer is specifically designed to measure the density of the electrolyte solution in a lead-acid storage battery. This density is directly related to the state of charge of the battery. As the battery discharges, the density of the electrolyte decreases, while it increases as the battery is charged. By comparing the specific gravity readings obtained from the hydrometer to standard values, one can accurately assess the state of charge of the battery.

While the voltmeter and multimeter can provide insights into the battery's voltage, they do not directly quantify the battery's charge state in terms of electrolyte composition. A hygrometer, which measures humidity, is not relevant in this context. Therefore, the hydrometer is the most appropriate instrument for determining the charge state of lead-acid batteries.