You might be misunderstanding what the product is offering.
There is no battery contained in this charging cord.
You must plug into an existing 5-15 outlet to gain power for the charge.
It is only "portable" in the sense that it packs up into a case for easy transportation in the trunk while driving.
If there is no 5-15 power outlet available to you, this unit will provide no charging.
To the extent that you can plug it into a NEMA 240v outlet that provides 32 amps, yes, it should give you 31 miles per hour charging.