if the battery is down to absolute zero the charger simply doesn't turn on because it can't tell it's hooked up to anything. The NOCO has a "Force" mode that turns on the charging regardless, until there's enough juice there to resume normal smart charging.
My motorcycle shop used one of these to "wake up" a dead battery so a normal charger could work. Basically using it as a "dumb" charger to get a little juice into the battery before moving it to a smart charger.
DC Power Supply Variable,30V 10A 4 Digital LED Display Adjustable Regulated Switching Power Supply Digital with Leads Power Cord (30V 10A Black) https://a.co/d/fwIwEwU