A cycle count comes from a defined test: charge to a defined level, discharge at a defined current to a defined cut-off, repeat until capacity falls below a defined fraction of the original — usually 60 or 80 percent. Change any of those four definitions and the number changes with it.

This is why cycle claims from two suppliers are rarely comparable, and why the useful question is not "how many cycles" but "measured how". Ask for the test conditions alongside the number.

In practice, how the cells are treated matters more than the rating. Deep discharges, charging in the cold and leaving cells flat in storage all shorten life faster than the difference between a 1200-cycle and a 1500-cycle rating.

Use this checklist

  • Ask for discharge current, cut-off voltage and the end-of-life threshold
  • Compare test conditions before comparing cycle counts
  • Usage patterns usually matter more than the rating
  • Put storage and charging guidance in the manual