My ZAP uses the Curtis motor controller. I don't have any data or schematics, but I think it operates as a PWM type of device, at a frequency of about 3 KHz as judged from the tone of the whine it makes on the AM radio.
I think it operates like this: At any moment in time when energy is being delivered to the motor during the "ON" portion of the PWM duty cycle, the motor sees full battery voltage. As such it pulls a high amperage based on the full battery voltage and the resistance of the motor windings, less any inductive effect to slow down the current transient spike. This momentary current will be much higher than the average amperage I read from the ampmeter....I think. A battery operated o'scope would be nice to capture the actual voltage spikes across the battery shunt, then I'd know exactly what's happening by calculating the peak amperage associated with those spikes.
But I'm assuming someone reading this already knows the energy characteristics involved here.
My question is: If there are high amperage spikes based on the PWM usage of the motor controller, even at low average amperage usage at partial "throttle", would I benefit by adding a large capacitor bank across the battery pack output? The caps could provide the peak energy into the motor at the high pulse amps, while the battery pack would only see the average amperage as it recharges the caps. Thus could I get more range out of my lead acid pack since the Peukert effect would be based on a lower amperage value?
I think it operates like this: At any moment in time when energy is being delivered to the motor during the "ON" portion of the PWM duty cycle, the motor sees full battery voltage. As such it pulls a high amperage based on the full battery voltage and the resistance of the motor windings, less any inductive effect to slow down the current transient spike. This momentary current will be much higher than the average amperage I read from the ampmeter....I think. A battery operated o'scope would be nice to capture the actual voltage spikes across the battery shunt, then I'd know exactly what's happening by calculating the peak amperage associated with those spikes.
But I'm assuming someone reading this already knows the energy characteristics involved here.
My question is: If there are high amperage spikes based on the PWM usage of the motor controller, even at low average amperage usage at partial "throttle", would I benefit by adding a large capacitor bank across the battery pack output? The caps could provide the peak energy into the motor at the high pulse amps, while the battery pack would only see the average amperage as it recharges the caps. Thus could I get more range out of my lead acid pack since the Peukert effect would be based on a lower amperage value?
