The vehicle over a 500 mile journey at 55 mph would take just over 9 hrs. I've assumed 60 hp over 9 hrs (this would also include braking and accelaration losses). The total energy for the 500 mile 9 hr trip is calculated at 406.7 kilowatt hours or 545.5 Horse power hrs or 1464.4 MegaJoules.

To store that amount of energy in a battery i,e to charge the battery in 5 minutes (300 seconds) (lets forget the energy convertion losses of the charger electronics for the moment)

So Power = Voltage * Current

and Total Energy = Power * time

Therefore Power = Total Energy /time = 1464,400,000/300 = 4,881,333 Watts or 4.881 Megawatts

Assuming a 95% effeciency this takes the power required to charge the battery to 5.12 Megawatts.

Therefore Current = Power / Voltage = 5,120,000/220 = 23272 Amps