If the battery is charged several times after partial discharge, the battery gradually loses its useful capacity due to a reduced operating voltage. Users of nickel-cadmium and nickel-metal hydride batteries are mostly aware of the memory effects of such batteries.
The battery is said to have 'remembered' the previous minimum capacity. It is a state in which the nickel-cadmium or nickel-metal hydride batteries systematically lose their maximum energy storage capacity when the batteries are repeatedly charged after it has been partially discharged (for instance, if the battery is discharged to 60%, when it is recharged, the battery remembers and somewhat returns to the former -60% capacity). The memory effect, which is also known as the battery effect, the lazy battery effect or battery memory effect, occurs in rechargeable nickel-cadmium and nickel-metal hydride batteries, and it results in the batteries holding a reduced charge.
