You need to spin the motor faster, and/or test it under load.
That’s what I’m saying. It is under load. And that load is my holding it back with one hand.
Until it spins faster, you won’t be getting much power output at all.
Your hand is not going to be a suitable tool for that drag simulation.
Try connecting the driven motor to another motor with all 3 phases shorted out to provide drag.
I’ve taken it on the road and it can barely move on a flat surface.
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Send screenshots of all the motor settings after clicking “Read motor settings” on the right side while connected to the desktop version of the Vedder tool.
@Differentunic1 What motor is it? What KV rating does it have? Is it a hub/direct drive motor, or is it geared? What’s the gear ratio?
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I just went out for another test drive, and it still doesn’t work. The issue is definitely that it is only outputting a very low voltage to the motor. It also reduces the efficiency of both the vesc and the motor.
The 40kv is only something I calculated. It’s rated at 2400rpm at 60v. It’s a standard Chinese HM60v3000w
40kV is very high for a motor of that size, and if that is the case, it could definitely explain some of the problems you’re having. I wouldn’t expect that motor to exceed 40km/h under load according to my simulation due to terrible efficiency (less than 60%), whereas a 25kV motor should be able to do closer to 50km/h due to the better “gearing” that kV gives.
25kV is probably the best in terms of maximum speed, 20kV or even 18kV would get you the same ~40km/h as the 40kV, but the efficiency would be better - 75% rather than 60.
Basically the motor is wound too fast, so it loses torque.
You also seem to not understand how brushless motors and ohm’s law works very well. The winding resistance (DC resistance) is extremely low, probably less than 0.1 ohms in the case of this motor. If you were to connect it to a constant-current power supply set to 45 amps, you would see V=I/R across the motor’s winding resistance, or V=45/0.1, or 4.5 volts. If you raised the voltage, the current would also increase beyond 45 amps. This is why at low speed, the voltage at the motor is very low compared to the battery voltage.
As the motor’s speed increases, it begins to act as a generator, producing a voltage proportional to its speed, in opposition to the supply voltage. This opposing voltage, called “back-EMF”, is what causes the motor to require more voltage as the speed increases: To continue pushing 45 amps of current through the motor, the supply voltage must be 4.5 volts above the back-EMF voltage.
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With my old controllers, I was able to reach 120km/h and going up pretty steep hills about 60km/h. With this controller, I can’t even go up a flat road. Is there any way to force a higher voltage, because that is the issue.
No, and no.
There is definitely something wrong with your setup, but unfortunately you can’t just cram more volts down it to solve the issue.
Do you have a clamp-type amp meter to actually measure the motor phase current?
Telemetry from the ESC would work as well.
I only have a probe type multimeter. How would I set up the vesc to get reading? Do you mean the real time data gauges?
Realtime data would work.
It would be preferable to have something like a Metr pro so that the person riding the vehicle isn’t also the one that has to look at the data, but it’s not absolutely required.
I’m able to log data on my phone from the vesc if that’s something that would work?
At 16s that direct drive hub motor will be doing 68mph. You are going to need a lot of torque (which you get from motor amps) to have a reasonable acceleration. Most esk8s running 2x 80A motors are geared for about 30-40mph to have a nice balance of acceleration and top speed.
That motor is sold with a standard Chinese KT style 12 fet “45A” controller. Those old school 8 bit controllers work completely different than a VESC controller. They limit the battery current with stock firmware. When they say 45A, they mean 45 battery amps. When you give it full throttle, a lot more than 45A of motor current will be sent to the motor when duty cycle is low like at take-off.
TLDR; Crank up your motor amps to at least 100A, if not 120A. Battery amps can be 45A. Even 2x motors and 2x 75100s are going to struggle to power that thing with such tall gearing. That’s why the Rion scooters which have similar motors are running 2x250a VESC Tronic controllers.
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So should I sell my 75100s and get a higher amperage esc?
When I did set the vesc to 200 amps, I worked just like the original controllers, but quickly overheated.
Just checked the price of the vesc tronic controllers, and there is no way I can afford that. Plus the heat that they would produce is probably too much from sitting in a enclosed case in my scooter.
It may be worth trying the two 75100s with amps turned up and an added heatsink in airflow… but it would be hard to beat the cost of a pair of 12, 18 or 24 fet KT controllers running open source firmware.
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