We love grilled sweet potatoes. Just peel and slice into uniform slices. I usually make mine about 1". Drizzle with olive oil and S/P. Grill until a knife pierces them easily. They cook quickly and will burn if heat is too high. So watch them carefully.
I melt a couple tablespoons of butter and brown sugar and drizzle this over the cooked potatoes. Always nice to be able to cook on the grill and keep the kitchen cooler.
Hope you enjoy!