I have Schumacher charger with 70amp boost that goes automatically into desulfating mode when it sense low battery.
The manual did not explain it at all and drove me crazy for some time when suddenly charging the batteries took 5 hr @ 25 amp. Only searching the net and phone confirmation with manufacturer give me full explanation.
Anyway, the batteries on my Superduty were loosing the charge after 3-4 days.
70 months old, but with 100 months warranty, so I hooked up the charger and let it run desulfation without disconnecting from the truck (but ignition off).
Desulfation did not help the batteries and nothing happen to the truck.