🔍 Key Concepts

• State of charge of a lead-acid battery depends on the electrolyte condition • Different meters measure pressure, electrical resistance, density, or thickness/flow • Lead-acid battery electrolyte is a mixture of sulfuric acid and water whose specific gravity changes with charge

💭 Think About

• Which instrument is commonly used to measure the specific gravity (density) of liquids like battery electrolyte? • Which option is normally used to measure electrical resistance and would not directly tell you the battery’s state of charge? • Which instrument on the list is associated with pressure measurements, not batteries?

✅ Before You Answer

• Identify which choice is used to measure specific gravity of liquids • Eliminate the instrument that measures pressure of gases or fluids • Eliminate the instrument that measures electrical resistance in ohms, since that is not how we normally check state of charge in a lead-acid battery