All Morningstar PWM type controllers have a PWM switching frequency of ~300Hz.
Some Morningstar PWM controllers have a feature which will reduce the switching frequency to ~1Hz (called on/off charging). This on/off charging virtually eliminates switching noise (both radiated and conducted) and can be used when experiencing noise problems with 300Hz switching operation.
Current models with this on/off charging option are:
– SunSaver Generation 3
– SunSaver Duo
– ProStar PWM
– TriStar PWM