Cutting PowerA battery string trimmer’s cutting power directly corresponds to the size of its motor. Line ThicknessHigh-powered string trimmers use a thicker cutting string, also called a line, which can cut through heavier vegetation–think tall, overgrown weeds. Line FeedThe Nylon cutting line of your string trimmer wears out over time. WeightIt’s important to buy a string trimmer that feels light in your hands. Even within the world of battery-powered string trimmers, variations in battery and motor size can lead their weights to vary significantly from model to model.