I recently purchased a Schumacher SC1309 battery charger to replace an old Die Hard charger that failed. Compared to my previous charger, the new unit offers much higher charging rates, along with some new features. Of those features, the most interesting being the ability to desulfate a battery. So, how does it perform? It works quite well. Being a smart charger, it uses intelligence to determine the appropriate charging voltage, based on battery condition.