How To Manage Cogging on Tekin RX4 ESC

[AKayl]

Many of us have experienced poor startup with the Tekin RX4, and enough people have them that I thought I would post my results of how to get it to start smoother.

Lets start with the cause, then we will move on to what can be done to mitigate it.

I do not have an oscilloscope or really any electronics training other than just tinkering, so take my findings with a grain of salt. All of my testing is based on changing esc settings and driving a truck. What I have found is that the difference in brake and drive frequency is the cause of the rough startup that looks like cogging of a sensorless system. This problem is made worse by active drag brake, and drag brake strength, however I believe that these settings merely hide the issue and are not the root cause. Based on this what I think what is happening is Tekin is using fixed frequencies for brake and throttle. This causes a noticeable switch when the frequencies change between brake and throttle, active drag brake makes this more noticeable, I believe, because it is essentially switching back and forth between brake and throttle to create the desired effect. It is my belief that Tekin could fix this by using the set frequencies as a start and end point and vary the frequencies based on throttle input, this is something we don't have the ability to do with Hotwire, maybe if someone from Tekin sees this they can look into this. (doubt)

So what can be done to improve performance now?
In short set the throttle and brake frequencies as close as possible, you can also reduce drag brake and turn off active drag. The issue also seems to be nearly non existent at 2s, but no one uses 2s anymore so that is a bit irrelevant. I have posted the tune that I am currently using in my Tekin trucks on my google drive, it can be found here.

It is a shame that what I believe to be very high quality hardware from a family owned American company has such a well documented known issue that has existed for years and has not been addressed. That being said these tips can help you wind up with a very useable ESC, my biggest complaint with my tune is that it is louder due to the lower throttle frequency, however, it is very smooth.

I hope this info will help some folks be able use ESC's that may be on their way to being sold, or sitting in a parts drawer labeled unusable.