**Battery Glossary**

Primary Cell: An electrochemical device that is discharged only once and then discarded. Alkaline batteries are an example.

Secondary Cell: Anelectrochemical device that may be discharged and recharged a number of times. Li-Ion batteries are an example.Battery Capacity: The ampere-hoursavailable from battery.Battery Float Voltage: A constant voltage applied to a battery to maintain the battery capacity.Amp Hour or Ampere-Hour : A unit of measurement of a battery’s electrical storage capacity. Current multiplied by time in hours equals ampere-hours. One amp hour is equal to a current of oneampere flowing for one hour. Also, 1 amp hour is equal to 1,000 mAh

C : Used to signify a charge or discharge rate equal to the capacity of a battery divided by 1 hour. Thus C for a 1600 mAh battery would be 1.6 A, C/5 for the same battery would be 320 mA and C/10 would be 160 mA. Because C is dependent on the capacity of a battery the C rate for batteries of differentcapacities must also be different.

Cycle Life : For rechargeable batteries, the total number of charge/discharge cycles the cell can sustain before it capacity is significantly reduced. End of life is usually considered to be reached when the cell or battery delivers only 80% of rated ampere- hour capacity. The life of a rechargeable battery operating under normal conditions is generally between 500 to 800 charge-discharge cycles. The cycle of a battery is greatly influenced by the type depth of the cycle (deep or shallow) and the method of recharging. Improper charge cycle cutoff can greatly reduce the cycle life of a battery.

Energy Density :Ratio of cell energy to weight or volume (watt-hours per pound, or watt-hours per cubic inch).

Memory Effect : A phenomenon in which a cell, operated in successive cycles to less than full, depth of discharge, temporarily loses the remainder of its capacity at normal voltage levels (usually applies to Ni-Cd cells). Note, memory effect can be induced in NiCd cells even if the level of discharge is not the same during each cycle. Memory effect is reversible.

Self-discharge: A phenomenon that an active material is transformed into the discharge condition even in the state of open external current circuit is called ’ self-discharge’.