I want revive a battery and was going to buy a desulfator only. But I can across battery chargers with built in desulfators. problem I have is how do you know if the charger is going to go into desulfation mode when you want it to. I want it to recover a sulphated battery but it the charger just might charge it and skip the desulfation part. Do the desulfator chargers work or do i need to get a specific desulfator device?