3v when doing a discharge test is fine. The battery will sag under a load. The more you load it (current) the greater the voltage sag. So when the charger stops at 3v under the load. The battery, once rested for 10 minutes or so should bounce back to around 3.4v or so. Perfectly acceptable for li-ions. The newer Panasonics can be discharged down to 2.5v under a load. So it also depends on the battery being discharged. Li-ions are considered dead at around 3.4v or so when measured at rest (does depend on battery). So if a light drawing 3 amps stops working because the low voltage protection kicks in from either the battery or driver, the battery isn’t actually at 3v at rest. Once its allowed to rest the voltage will be much higher than the protections trip voltage.
Try here, going down to about the middle of the thread under HKJ’s table’s.