Thinkpads Forum

Does the battery count the cycle when you you completely charge and discharge?

How is this done? Always pondered this.

The "cycle" count is the equivalent of full discharge cycles. While this is not a rigorous explanation of what goes on, it goes something like this.....

• If you have a fully charged battery and fully discharge it, the cycle will increment by one (1) cycle count.
  
  If you have partially discharged battery and partially discharge it further, you will have performed some percentage of a full cycle. The processor in the battery tracks charging/discharging and adds up the less-than-full-cycle percentages, until you have reached the equivalent of a full cycle and then increments the cycle count by one (1).
  
  For a variety of reasons (not the least of which is chemical aging of the Lithium Ion battery cells), the adding up of the percentages shows some drift over time, so a periodic (every several months) resetting of the battery by performing one (only) deliberate full cycle is desirable.

Cheers,

Bill B.

thank you. Just what I needed to hear.

Well deep discharge wears more than shallow, so cycle count isn't that reliable.