Which battery chemistry uses constant-current charging and is resistant to overcharging?

Which battery chemistry uses constant-current charging and is resistant to overcharging?

• A. Lead Acid
• B. Lithium-Ion
• C. Ni-Cad
• D. Zinc-Carbon

Answer: (C)

Charging with a constant current means the charger pushes the same amount of current into the cell while the voltage rises as the cell fills. Nickel–cadmium cells are designed for this mode, and they tolerate a bit of overcharge without immediate harm, so they’re described as resistant to overcharging. Other chemistries behave differently: lithium-ion needs a precise constant-voltage finish after the initial current limit and is sensitive to overcharging without protection; lead-acid charging is usually voltage-controlled to prevent gassing and water loss; zinc-carbon isn’t well suited to repeated proper charging. So the chemistry that fits constant-current charging and shows resistance to overcharging is nickel–cadmium.

Charging with a constant current means the charger pushes the same amount of current into the cell while the voltage rises as the cell fills. Nickel–cadmium cells are designed for this mode, and they tolerate a bit of overcharge without immediate harm, so they’re described as resistant to overcharging. Other chemistries behave differently: lithium-ion needs a precise constant-voltage finish after the initial current limit and is sensitive to overcharging without protection; lead-acid charging is usually voltage-controlled to prevent gassing and water loss; zinc-carbon isn’t well suited to repeated proper charging. So the chemistry that fits constant-current charging and shows resistance to overcharging is nickel–cadmium.