In a large cast iron skillet over medium heat, cook bacon until crispy. Remove to a paper towel-lined plate. Discard bacon fat in the pan. In a food processor fitted with the grater attachment, push potato, onion and garlic through the grater. Remove mixture to a towel and squeeze out excess liquid. Place potato mixture in a large bowl and mix in sage, eggs, flour, cooked bacon and salt and pepper, to taste. Fill the skillet with 1/4-inch of vegetable oil and heat until it ripples. Once the oil is preheated, form potato cakes, measuring roughly 3 inches in diameter, and add to the pan. Continue forming patties, working in batches. Cook pancakes until crispy and nicely browned, pressing down on the pancakes periodically to flatten, about 2 minutes per side. Remove to a paper towel lined plate. Keep cooked pancakes warm in a preheated 275 degree F oven while remaining pancakes cook.