Oh good, it's rant time! :)
I wish "they" did not call the different voltages in converters "stages" which term, IMO should only be used with the stages of charging a battery (bulk, absorb, float)
A single voltage charger will do two stages (bulk, absorb) it just will not do float--it stays at its Vabs which is probably too high in voltage for a float.
So everybody has to stop right now and stop calling those single voltage chargers "single stage" because they are actually "two stage" Rambling Wrecks are supposed to know this.