Which statement best describes the end-of-charge voltage for a 19-cell nickel-cadmium battery during charging?

Which statement best describes the end-of-charge voltage for a 19-cell nickel-cadmium battery during charging?

• A. It depends upon temperature and the method used for charging
• B. It depends solely on the ambient temperature
• C. It depends only on the electrolyte density
• D. It is fixed and identical for all 19-cell batteries

Answer: (B)

End-of-charge voltage in a nickel-cadmium pack is not a fixed value; it shifts with temperature because the cell chemistry changes with temperature. For a 19-cell NiCd pack, the per-cell end voltage at full charge, and thus the total pack voltage at end of charge, depends on the ambient temperature. In practice, this means the voltage you observe at the point you consider “fully charged” will vary as temperature changes, so the overall end-of-charge threshold is governed mainly by temperature. While charging method and electrolyte density influence how heat is generated and how quickly the pack reaches that point, they do not set a universal end-of-charge voltage independent of temperature, making the ambient temperature the primary factor described by the statement.

End-of-charge voltage in a nickel-cadmium pack is not a fixed value; it shifts with temperature because the cell chemistry changes with temperature. For a 19-cell NiCd pack, the per-cell end voltage at full charge, and thus the total pack voltage at end of charge, depends on the ambient temperature. In practice, this means the voltage you observe at the point you consider “fully charged” will vary as temperature changes, so the overall end-of-charge threshold is governed mainly by temperature. While charging method and electrolyte density influence how heat is generated and how quickly the pack reaches that point, they do not set a universal end-of-charge voltage independent of temperature, making the ambient temperature the primary factor described by the statement.