[X8G]

I have a Chinese low speed electric vehicle. The car was supplied to me with a 3.5kw motor by mistake when the specification quoted 4kw motor. The company quickly sent me a 4.2kw motor by FedEx.

The speed etc is exactly the same as with the 3.5kw motor. Speed is limited to 40kph. I have no idea how the controller can be reprogrammed. Both motors have a hall sensor pulse counter on the back of the motor and a rotor with 48 slots. If the number of slots is reduced the number of pulses will be lower so will the controller be fooled into thinking that the car is going slower and thereby give me a higher speed?

I live in the Republic of Georgia where LSEV is not recognised so I have no liability to drive the car as a LSEV.

Any suggestions would be appreciated

 

[brian_]

What you can do depends on what that sensor is being used for, and that depends on the type of motor. Do you know what type it is? Even a brand and model number of the controller would imply the type of motor, if it is a well-known brand.

 

[X8G]

The motor is a Depuda 3 phase 102hz 4.2kw motor
As a matter of interest. Everything seems to be inaccurate so far as the instruments are concerned. Speedo reads 55-60 instead of true reading of 40kph. Rev counter is reading too high. State of charge I suspect is incorrect and temperature gauge reads high

 

[brian_]

The controller needs a speed signal (if it is an induction motor) or shaft position signal (if it is synchronous motor) to operate the motor... unless is it running on feedback from the motor ("sensorless"). If the controller is using that hall-effect sensor (which would only be good for speed), you can't change the scaling. If it's a synchronous motor it would have a separate encoder, and the pulse sensor could probably be re-scaled.

Depuda's product page says that they make both types, including various induction motors around that power (but none at specifically 3.5 kW or 4.2 kW), and synchronous motors (all of which are much larger).

 

[X8G]

 

[X8G]

The photo is the actual replacement motor they sent me which is a direct plug in replacement.

I noted that if I disconnect the hall device the car simply does not move at all so no feedback from the sensor gives no drive.

 

[brian_]

The photo is the actual replacement motor they sent me which is a direct plug in replacement.

The "XQY" part of the model name implies that it is an induction motor (following their naming convention).

The placard specifies 102 Hz, which for a 4-pole motor would mean 51 revolutions per second, or 3060 RPM; that corresponds to the 3000 RPM on the placard, but I don't know if that is the speed for rated power (likely), or a maximum speed. Do you know the gearing of the vehicle, to determine the corresponding road speed?

I noted that if I disconnect the hall device the car simply does not move at all so no feedback from the sensor gives no drive.

The hall effect sensor is presumably the speed input for the controller, and so it needs to be not just present, but correct, for the motor to work.

 

[X8G]

Thanks for that Brian. I have no idea of the gear ratio of the final drive which is not mentioned in the specification sheets. I also wonder if it is in fact the correct ratio which was intended to be on the vehicle. The reason for doubt is that I see axles are usually provided coupled with a motor. The specification was 4kw motor but as a Depuda 3.5kw motor was supplied, it may be a different axle too.

Another reason for doubt is that the speedometer reads 55 - 60 kph but GPS reads 40kph which could signify an incorrect axle ratio.

Bottom line is... What is needed to increase the performance? I have no means of reprogramming the controller.

 

[X8G]

 

[X8G]

I note that the same company manufactures an electric truck with a rated speed of 35 kph and I wonder if the axle from this vehicle had been installed.

 

[brian_]

I have no idea of the gear ratio of the final drive which is not mentioned in the specification sheets. I also wonder if it is in fact the correct ratio which was intended to be on the vehicle. The reason for doubt is that I see axles are usually provided coupled with a motor. The specification was 4kw motor but as a Depuda 3.5kw motor was supplied, it may be a different axle too.

Another reason for doubt is that the speedometer reads 55 - 60 kph but GPS reads 40kph which could signify an incorrect axle ratio.

I note that the same company manufactures an electric truck with a rated speed of 35 kph and I wonder if the axle from this vehicle had been installed.

I think you mean "transmission" or "gearbox" rather than "axles"; axles are just the shafts connected to the wheel hubs. The term "axle ratio" refers to the ratio of the gearing in the final drive mounted at the axle.

Yes, it would make sense if your vehicle has a transmission system with a greater overall reduction ratio (ratio of motor speed to wheel speed) than intended for your vehicle and expected by the speedometer.

Bottom line is... What is needed to increase the performance? I have no means of reprogramming the controller.

If you change the overall drive ratio for less reduction the road speed for the same maximum motor speed would be higher; unfortunately, acceleration will be slower. Someone may have already changed the gearing to what it is now for better acceleration but lower top speed.

 

[X8G]

In the UK we refer to the rear drive setup simply as the rear axle and the axles connected to the wheels, not as axles but as the drive shafts. We are both talking about the same thing but using our own terminology. Yes, I think that without changing the axle with one incorporating a different ratio differential, any changes are going to be more difficult.

Of course I realise the implications of changing the axle with one incorporating a different ratio differential but acceleration is of little interest to me compared to a rather pedestrian 40kph top speed.

No-one has changed anything on the car as I bought it new and received it myself as sea cargo. Any mistake has been made by the manufacturer who does not answer my messages.