Current technological capabilities should be sufficient to supply maximum continuous current at freeway speed up a 6 percent grade in a gear with enough torque to not to slow down. The Advanced DC 9″ FB1-4001 electric motor can supply more power then an 8″ 203-06-4001, but not at 96 volts where power output is about the same and the FB1 is running slower then the 203.
At 144 volts you can push the current to get more torque from an FB1 that is beyond the continuous rating of an 203. Advanced DC also makes an 8″ XP=1227A that is designed for 240 volts. The tester of this study, Russ Lemons would not recommend use of the FB1 with battery voltage less then 132 volts or over 156 volts. Motor speed should not exceed 5500 rpm.
Russ would also not recommend use of the 203 with battery voltage less than 96 volts or over 132 volts. Motor speed should not exceed 6500 rpm. Even though the Curtis Controller can handle up to 500 amps, running at high currents is not good for the motor or the battery and will shorten their lives. It is better to slow down and drop down a gear then to overheat the motor. (Source: Russ Lemons)