Battery string lights longevity is significantly influenced by the quality of materials used in their construction. High-quality batteries and durable LED bulbs contribute to longer-lasting lights. According to a study by the National Electrical Manufacturers Association (NEMA), LED string lights with premium batteries can last up to 3 times longer than those with standard batteries. Additionally, the use of weather-resistant materials can extend the lifespan of outdoor battery string lights, ensuring they remain functional in various weather conditions. For instance, a survey conducted by the Consumer Electronics Association (CEA) found that outdoor battery string lights made with UV-resistant materials lasted an average of 2 years longer than those without such protection.