🔍 Key Concepts

• Difference between Edison (nickel-iron) cells and lead-acid batteries • How specific gravity of the electrolyte behaves in different battery types • Use of voltage measurements and discharge curves to estimate state of charge

💭 Think About

• Ask yourself: In which type of battery does the specific gravity of the electrolyte change noticeably with charge and discharge? • Consider whether an Edison (nickel-iron) cell’s electrolyte gives a reliable indication of state of charge. • Think about why engineers create standard discharge curves and how they are used along with voltage under load.

✅ Before You Answer

• Identify whether an Edison cell is an alkaline or lead-acid type battery. • Verify if the electrolyte specific gravity of an Edison cell changes enough with charge to be used as an indicator. • Confirm how terminal voltage under load and a standard discharge curve are typically used to estimate state of charge.