The difference is in the MGFlex motor 

The MGFlex motor is optimised for converting photovoltaic DC power to AC, producing output identical to a standard variable frequency drive, and also works with other Grundfos pumps. 

Maximum power 24/7

Maximum power point tracking (MMPT) monitors the pump’s own power generation several times per second and makes sure it runs at maximum at all times. 

The best solution

No energy use from a renewable source, ensuring a cost-effective, flexible and secure water supply solution.  

Automatic operation

Built-in motor protection against overload and low voltage ensures that the pump operates in a wide voltage range.