The period during which a system is capable of operating above a specified performance level.

1. Someone or something that has an active physical presence and behaviours, e.g. consumes nutrition, grows, etc.: The lives of famous people have been recorded in many books and movies.

The earthquake claimed hundreds of lives.

2. The habits and expectations of inhabitants of a particular place: Some people prefer city life while others want country life.
3. The time from birth to death: Life begins when a person is born and ends when he or she dies.

Jarrod knew what he wanted to do early in life.

The length of time, at a specified temperature, that a charged battery can be stored before its capacity falls to an unusable level.

The number of cycles, to a specified depth of discharge, that a cell or battery can undergo before failing to meet its specified capacity or efficiency performance criteria.

The period during which a cell or battery is capable of operating above a specified capacity or efficiency performance level.

Life may be measured in cycles and/or years, depending on the type of service for which the cell or battery is intended.

The number of years that a battery can keep its stated capacity when it is kept at float charge.

A calculation, based on statistical data, of the average life span of an organism.

The estimated cost of owning and operating a photovoltaic system for the period of its useful life.

The length of time, under specified conditions, that a battery can be stored so that it keeps its guaranteed capacity.

The period of time that a charged battery, when filled with electrolyte, can remain unused before dropping below a specified level of performance.