Many chargers, such as B. the Noco models have this depressingly loud fan that hums when the charger is running. In this unit, the fan will NOT run when not in use. The fan kicks in slowly when needed, and then only gets louder when there's too much heat. In fact, the fan is properly temperature controlled. And a fan is a real fan that moves air and doesn't use its full power to make a buzzing sound. Otherwise, it charges quickly. Used it to charge two Trojan T105 golf cart batteries in a solar