I have tried most of these options below and find that hand pump is always fastest around 12mins. The $55 amazon sup pump works great too but takes around 20mins per board. They can burn out if doing more than one board without a cooling break. I have repaired 2, they both blew a capacitor on the circuit board and burned out the main power wire at the circuit board. I also use a 30A alligator outlet direct to the car battery when running the isup pump. They can blow the 20A dash accessory fuse.

Compressors for car/bike tires are just not a good option for isups.
I have tried Ryobi 18V combo airbed inflator / tire compressor, it works for one board but slowly with the Schrader adapter. battery dies before filling 2 boards.
Car tire compressor with direct battery clips works ok but also very slow. I am seeing dual piston car compressors available now maybe those are faster.

Hope this keeps everyone pumped up