QS 205 V3 stutter or desync issues

Hello, I'm Max and since this is my first time here, I'd like to send out a big thank you to everybody posting on this great forum! 8) It already helped me quite a bit and I'd love to get involved more in the future.

Now, I'm building a 4 kW cargo eBike for city riding mainly, but I'm kind of stuck and could really use some help! Running a QS 205 50H Version 3 Motor on a 24 FET Infineon 24-IRFB4115-80A Controller at 24s Voltage (102 V). I have some issues with the motor stuttering quite hard and suddenly stopping at low speeds. I made a video of the problem to illustrate. The stuttering is quite violent moreso than you can see in the video. I'm thinking this might be a problem that has occured before or someone knows of the issue.

I already checked hall sensors with a multimeter and they seem to be okay. Also the three phase wires of the motor seem to be okay on a first check (held them together and felt quite some resistance when turning over the motor). Still, my next step would probably be to disassemble the Motor and check all wiring, I'm suspecting a half broken phase wire. Do you guys agree, or could it be a controller issue? Or a problem with the power supply? I'm running on two 51V power supplies in series at the moment, as I don't have the battery ordered yet.

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I think you need to wait for your Battery first. Unless those two power supplies can output more than the motor is consuming under load, which is highly unlikely.

Why such a light controller with only 80A? What T winding do you have? A T4 winding can take 150 battery amps and 300 phase amps at 72V.

And the reason why it craps out is simple: those power suplies are way too weak to handle the load that controller can pull.

Come back when you have a battery that can actually deliver 130ish amps at 100+ volts

Hey thanks for the help and the suggestions, I‘ll post here on the results hopefully soon. I was planning on using these power supplies for charging the self built 24s30p battery, anyone has experience in using simple power supplies for charging?

Lots of threads on that. Lookup Meanwell to find many of them.

Allright, I'm back with my battery, it's a 28s28p made out of 18650 cells. Used this BMS and it works well:
https://www.aliexpress.com/item/28S-150A-lithium-lipo-Polymer-BMS-PCM-PCB-battery-protection-board-for-28-Pack-18650-Li/32846538582.html?spm=a2g0s.9042311.0.0.5ef14c4dbYmN0c

With the battery the motor works fine now, you were right about that, thanks again for your last answers.

But I have a new problem now: The throttle controls speed of the motor, not battery current. This is quite unusable because it gives full power until speed is reached. Guess I need a new controller since the CA current throttle did't help much (huge oscillations).

Would a Kelly Controller help with this issue?

Yeah a kelly would help, but not the sinewave KLS version. It's the only Controller that doesn't have a torque throttle setting.

max85194 said:

Would a Kelly Controller help with this issue?

Click to expand...

yes, you have a 24S battery or plan to get one, you need a high voltage controller capable of hitting 300A:

http://kellycontroller.com/kls8430h24v-84v300asealed-sinusoidal-wave-bldc-motor-controll-p-1453.html

and yes, this has torque trottle.

ask QSmotor for the right battery and phase amps you motor can handle at 105V so you dont turn the motor windings to plasma.

That sounds good, thanks. Do you recommend the KLS8430H for having precise throttle control at low speeds? Since this is mainly a city scooter I want it to be as easy as possible to handle. I also would love to have smooth acceleration from 0 km/h. As I said with my generic Infineon 24 FET the motor shakes back and forth loudly from standstill and I shure would like to get rid of this.

You can set the trottle midpoint manually. So you can have most of your trottle be low power and once you go over that point you get the rest. You can also connect a low speed switch that limits the rpm to a set limit, handy for manuvering for example so you dont dart off if you hapoen to drop off a curb and go full trottle for a second.
If you have a motor this powerful you need to put some care into setting the trottle and stuff.
You can also have a button for full regen power so you never have to touch the brake.
The kls is a sinewave controller so it does not make any noise when moving at any speed.