Which statement correctly distinguishes amp-hours from cranking amps?

• A. Amp-hours indicate instantaneous current capacity.
• B. Cranking amps indicate energy storage over time.
• C. Amp-hours indicate energy storage over time; cranking amps indicate the ability to deliver high current for starting.
• D. Cranking amps indicate voltage stability.

Answer: (C)

Amp-hours measure how much energy the battery can store and deliver over time, which is its capacity. Cranking amps, on the other hand, describe the maximum current the battery can supply in a short burst to turn over an engine, i.e., its peak current capability for starting. So amp-hours reflect energy storage over time, while cranking amps reflect the ability to deliver high current for starting. Voltage stability isn’t the defining feature of cranking amps; it’s about the ability to provide a high current quickly, even though voltage may dip under heavy load.