You can look at it that way. But you have to remember that you use the batteries to get you to and from the start, to the bar, etc. The key is that if you only use the cart a minimum for other than racing you should be able to completely charge the cart in about 20 to 25 minutes.
Remember the example I used was 486s. Your present batteries, if I remeber correctly, are basically 2 486s in parallel, so your total amp hour capacity is twice example given. If you are only using 72 volts, (less batteries voltage drop at high current, your not getting near 72 volts to the motor. Voltage has to be there for speed.
Voltage is = to the pressure to a water hose.
Current is the amount of water flowing through the hose. The more pressure, the more water will flow. The higher the voltage, the more currect will flow if the resistance stays the same. The size of the hose, the amount of couplings, etc. is the limiting resistance to the amount of water that can flow.
With electric power the current (I, measured in amps) is equal to the voltage (E) divided by the resistance (R, measured in ohms). That resistance is the internal resistance of the batteries, the resistance of the wires, the resistance in the controller, etc, but most of the resistance comes from the carts weight, drag, rolling resistance, and "other" resistance the motor is working to overcome.
If I=E/R, the R=E/I and (as normally stated as ohm's law, E=I*R.
Power measured in watts is equal to the voltage multiplied by the current. Power used is equal to the volage multipled by the current, or P=E*I, so, since E=I*R, by substitution, Power is also calulated as P= (I*R)*I, or P=I "squared * R). ALL this just means is that actual Power used to move the car with accelleration is based on having a lot of water pressure forcing a lot of water through a hose as fast as possible. The less resistance you have to the water
flow the more water you have to make the water wheel turn the axle.