Charge cycle

A charge cycle is the process of charging a rechargeable battery and discharging it as required into a load. The term is typically used to specify a battery's expected life, as the number of charge cycles affects life more than the mere passage of time. Discharging the battery fully before recharging may be called "deep discharge"; partially discharging then recharging may be called "shallow discharge".

A "charge cycle" is not a unit of time; the length of time spent charging or discharging does not affect the number of charge cycles.^[1] Each battery is affected differently by charge cycles.^[2][3]

In general, number of cycles for a rechargeable battery (the cycle life) indicates how many times it can undergo the process of complete charging and discharging until failure or starting to lose capacity.^[4][5][6][7]

Apple Inc. clarifies that a charge cycle means using all the battery's capacity, but not necessarily by discharging it from 100% to 0%: "You complete one charge cycle when you’ve used (discharged) an amount that equals 100% of your battery’s capacity — but not necessarily all from one charge. For instance, you might use 75% of your battery’s capacity one day, then recharge it fully overnight. If you use 25% the next day, you will have discharged a total of 100%, and the two days will add up to one charge cycle."^[8]

See also

• Deep-cycle battery

References

1. Preger, Yuliya; Barkholtz, Heather M.; Fresquez, Armando; Campbell, Daniel L.; Juba, Benjamin W.; Romàn-Kustas, Jessica; Ferreira, Summer R.; Chalamala, Babu (1 August 2022). "Degradation of Commercial Lithium-Ion Cells as a Function of Chemistry and Cycling Conditions". Journal of the Electrochemical Society. 167 (12): 120532. doi:10.1149/1945-7111/abae37. S2CID 225506214.
2. "Understanding the Trilemma of Fast Charging, Energy Density and Cycle Life of Lithium-ion Batteries". 1 August 2022.
3. "Powerstation im Test" (in German). 1 August 2022.
4. Tony Bove (2 February 2010). iPod & iTunes For Dummies, Book + DVD Bundle. John Wiley & Sons. p. 26. ISBN 978-0-470-59070-6. Retrieved 19 June 2013.
5. G. S. George (1 January 2007). Applied Science II. Technical Publications. p. 8. ISBN 978-81-8431-146-4.
6. United Nations (2009). Recommendations on the Transport of Dangerous Goods: Manual of Tests and Criteria. United Nations Publications. p. 394. ISBN 978-92-1-139135-0.
7. Davide Andrea (2010). Battery Management Systems for Large Lithium Ion Battery Packs. Artech House. p. 189. ISBN 978-1-60807-105-0. Retrieved 19 June 2013.
8. Batteries - Why Lithium-ion? - Apple