How can the state-of-charge of a nickel-cadmium battery be determined?

How can the state-of-charge of a nickel-cadmium battery be determined?

• A. By a measured discharge
• B. By measuring charge rate
• C. By electrolyte temperature alone
• D. By visual inspection

Answer: (A)

State of charge is best determined by measuring how much capacity remains through a controlled discharge. For nickel‑cadmium, you confirm how many amp-hours the battery can still deliver by discharging it at a known rate until a defined cut‑off, then compare the delivered capacity to the rated capacity. This direct measurement of usable energy left is what SOC represents. Other methods don’t give a reliable read of SOC. Measuring the charge rate tells you how fast you’re charging, not how full the battery is. Temperature alone doesn’t indicate how much energy is left, since temperature rises with current and internal resistance and doesn’t map reliably to remaining capacity. Visual inspection doesn’t reveal the actual energy stored.

State of charge is best determined by measuring how much capacity remains through a controlled discharge. For nickel‑cadmium, you confirm how many amp-hours the battery can still deliver by discharging it at a known rate until a defined cut‑off, then compare the delivered capacity to the rated capacity. This direct measurement of usable energy left is what SOC represents.

Other methods don’t give a reliable read of SOC. Measuring the charge rate tells you how fast you’re charging, not how full the battery is. Temperature alone doesn’t indicate how much energy is left, since temperature rises with current and internal resistance and doesn’t map reliably to remaining capacity. Visual inspection doesn’t reveal the actual energy stored.