Author Topic: VEC 300 Controller not getting past 35amps  (Read 2933 times)

Offline KaptainJEK

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VEC 300 Controller not getting past 35amps
« on: April 14, 2019, 07:43:10 PM »
Hello All,

My configuration is a 72v 5kw BLDC motor powered by the VEC300 Controller.  I have a Volt/Amp/Whr/W meter hooked up to my configuration and I am not getting any current over 35 amps.  I need more torque for my application but seems like if I can't get the rated current, I will never get the torque I need.

I have changed the settings on the VEC300 many many times and no configuration seems to get me at max.  Any ideas what I might be doing wrong?

Thanks all!

Offline Bikemad

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Re: VEC 300 Controller not getting past 35amps
« Reply #1 on: April 14, 2019, 09:40:01 PM »
If your controller is unable to pull more than 35 Amps, either the motor is running at too high an rpm (greater than 4000 rpm), or the Battery's BMS is unable to allow more power to be supplied to the controller.

If you look at the 72V dynamometer data figures, you should be able to see that the current will only go above ~35 Amps if the motor is loaded sufficiently to bring the rpm down below 4000 rpm using full throttle. The slower the motor rpm at full throttle, the higher the current draw will be.

I know at full throttle I am @ 6000 rpm.

This rpm seems to be a lot higher than the 72V dynomometer test, which indicates a maximum rpm speed of just 4259 rpm. Perhaps this test commenced with some load already acting upon the motor. :-\

The VEC300-72 has a rated current output of ~100 Amps, and this would require a loaded shaft speed (at full throttle) of less than 3600 rpm to draw 100 Amps (assuming that the battery's BMS can supply a constant 100 Amps).

What is the maximum constant current output of the battery you are using and what load is being applied to the motor shaft?

If the low current is due to high rpm, you will need to increase the gearing (or use a larger pitch and/or larger diameter propeller if it's a watercraft) to place more load upon the motor.

What torque (and rpm) do you need?

Alan
 
« Last Edit: May 05, 2019, 05:06:13 PM by Bikemad »