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ITGlossary · Batteries
Cycle Life
The number of charge and discharge cycles a battery withstands until its capacity falls, usually, to 80% of the original.
Technical level:Intermediate
One cycle is a discharge followed by the recharge that comes after it. The number of cycles is always given for a specific depth of discharge and temperature, because the same battery withstands far more cycles with shallow discharges.
It is different from service life in years. An office UPS goes through few cycles a year, and its battery ages mainly with time and temperature. A solar system with storage goes through about one cycle a day, so roughly 365 a year, and there cycles matter more.
When you compare datasheets, make sure the cycles are given for the same depth of discharge and the same end-of-life capacity limit.
Questions that mention it
All frequently asked questionsWhat are the main differences between AGM and GEL batteries?
AGM batteries have lower internal resistance and deliver higher power, while GEL batteries have a longer cycle life.
Related terms
- C-rateThe charge or discharge current expressed as a multiple of battery capacity, e.g. 1C for a 100 Ah battery means 100 A.
- Battery Service LifeThe years a battery keeps enough capacity, typically 3–5 years for VRLA at 20–25 °C, shortened by high temperatures.
- Deep-Cycle BatteryA battery designed to be discharged deeply and recharged again and again without wearing out quickly.
- Depth of Discharge (DoD)The share of a battery's capacity that has been drawn in a discharge, where 100% means fully discharged.
- Eurobat Design Life ClassesA classification of sealed lead-acid batteries by their design life on float charge at 20 °C.
- Fast ChargingA charging method that restores battery capacity quickly without damage by controlling current, voltage and temperature.