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The maximum discharge rate for a Ni–Cd battery varies by size. For a common AA-size cell, the maximum discharge rate is approximately 1.8 amperes; for a D size battery the discharge rate can be as high as 3.5 amperes. [citation needed]
Discharge efficiency Self-discharge rate Shelf life ... Cadmium: KOH Yes c. 1960 ... Low self-discharge nickel–metal hydride battery:
The Headway 38120HP cells are used in high-discharge environments as they have very good continuous/peak discharge rates (10C/25C). Because four cells in series produces a voltage range similar to 6 cells of lead-acids and their fire-resistant properties, they can be used to replace a 12 V lead-acid car battery. [235] 38140: 38140s 12,000 38: 140
Because the charging voltage is higher than the discharge voltage, the watt-hour efficiency of a silver–cadmium cell is about 70%; ampere-hour efficiency is about 98%. The usual recommended charging method is constant-current charging at a 10 or 20 hour rate, (restoring the capacity of the battery over 10 or 20 hours), and cut off of charging ...
Self-discharge rate: 20% [2] [3 ... invented the nickel–cadmium battery in 1899. Jungner experimented with substituting iron for the cadmium in varying proportions ...
Manufacturers specify the capacity of a battery at a specified discharge rate. For example, a battery might be rated at 100 A·h when discharged at a rate that will fully discharge the battery in 20 hours (at 5 amperes for this example). If discharged at a faster rate the delivered capacity is less.
Old rechargeable batteries self-discharge more rapidly than disposable alkaline batteries, especially nickel-based batteries; a freshly charged nickel cadmium (NiCd) battery loses 10% of its charge in the first 24 hours, and thereafter discharges at a rate of about 10% a month.
The practical shelf life of a Ni-MH is roughly five years. Cylindrical jelly-roll Ni-MH cells, like the ones used in 1990s laptop battery packs, discharge at a rate of up to 2% per day, while button cells like the ones used in motherboard batteries discharge at a rate of less than 20% per month. [13]