🔍 Key Concepts

• Chemical changes in lead-acid batteries during charging vs. discharging • Relationship between specific gravity of electrolyte and state of charge • Gases evolved or absorbed in a vented lead-acid battery when charging

💭 Think About

• Think about what happens to the electrolyte (sulfuric acid + water) as a battery goes from discharged back to fully charged. • Consider what happens to the lead plates during discharge and then how that process is reversed during charge. • Ask yourself: during charging, are gases mainly produced or absorbed, and which gas is most associated with overcharging a lead-acid battery?

✅ Before You Answer

• Recall whether the specific gravity of the electrolyte is higher when the battery is fully charged or fully discharged. • Review what chemical compound forms on both plates when the battery is discharged (and what happens to that compound when it is charged). • Verify whether hydrogen and oxygen are typically generated or absorbed during normal charging of a vented lead-acid battery.