What is battery life?
Battery life is the length of time a device can continue to work before it needs its battery to be recharged. Sometimes, this can also refer to a battery cycle life which is the number of charge/discharge cycles a battery can be expected to hold before it no longer holds a full charge.
Key Takeaways:
- Battery life is the amount of time a device can run before it’s battery needs to be recharged
- Battery life often refers to battery cycle life
- There are several factors that affect a battery’s life
Understanding Battery Life
Battery life is the length of time a device can continue to work before it needs its battery to be recharged when operating at room temperature and discharging at a moderate rate. This time is determined by many factors, such as temperature, the materials that a battery is made with, or how often it is used.
Sometimes, battery life refers to battery cycle life or ‘cycle fade’ which is the number of times that a battery can be charged and discharged before it no longer holds a complete charge. See Battery Cycle Life (link) for a full definition of this term. A typical life for nickel and lead-acid batteries tends to be 300-500 full cycles.
The full capacity of a battery also diminishes with age, even if cared for in ideal conditions. This is called ‘calendar fade’. Nickel-based batteries and lead-acid batteries are the most susceptible to this, while lithium-ion batteries are less so. The reason for this diminishing performance is due to unwanted chemical or physical changes to the active materials that make up the battery. Sometimes this is caused by elevated temperatures.
For instance, A fully charged lithium-ion battery kept at 40°C (104°F) loses about 35 percent of its capacity in a year without being used.
Ultra-fast chargers and harsh discharging is also harmful and can affect battery life.
Related Terms
Battery – A storage device for electrical energy, typically in a chemical solution, that can be used as a source of power.
Battery Cycle Life – The typical number of charge and discharge cycles that a battery can undergo before it reaches the end of its useful life.
Maintenance-free Battery – Batteries that typically come sealed for life from the manufacturer and do not require any maintenance of the electrolyte levels.