Now that I have the Opus BT-C3100 charger, I can see how my long time reliable and unreliable cells are doing.
I have a set of XTAR 2600mah 18650’s from the special many years back. They’ve been workhorses in my bike lights with countless hours on them.
As a matched set of 4, I got readings from 2100mah to 2250mah using the 1amp test cycle.
Although that is technically end-of-life, I can see them serving well putting out many more lumens before I retire them.