You'll want to create a two zone grilling situation: one side without the charcoal coals and one side with the coals. Start by placing the brats over indirect heat, the cooler side of the grill without charcoal. Grill for about 10-15 minutes, flipping over every now and then. Then move them over to the hot side of the grill and grill just for about 5 minutes, until the grilled brats get a nice char on all sides and reach an internal temperature of 160°F.