The Delco Remy 55SI alternator from Remy International has a durable brushless design and is rated at 420 A at 12 V and up to 275 A at 24 V. The compact 12-V model is commonly used on fire and rescue trucks, offering high-output performance at engine idle. Utility and work trucks can power inverters and plug-in power tools, lights, and other electrical equipment. The 24-V model meets the electrical load demand of transit buses, mining equipment, and other off-highway vehicles. One 55SI can replace a dual alternator system, freeing up underhood space for other accessories and reducing engine power requirements to improve fuel efficiency. Units also support the electrical load requirements of long haul trucks equipped with multiple battery auxiliary power units.