Sorry for the long topic. TL;DR Issue is visible on the graphs
The Problem
When I accelerate with my throttle at 70% with a kick push, the board ramps up in speed smoothly and reaches a certain speed, but If I accelerate with the throttle at 100% with a kick push, the board almost immediately loses power (as if it reaches some limits, not that the vesc turns off) and the acceleration/amps are limited/cut back and acceleration is somewhat halted or severely slowed down and it is not smooth but very jerky, as if it the belt is skipping (but i believe it is not, though i am only 90% sure). The same occurs for braking. If i brake with 70% throttle, it brakes with satisfactory power and it is smooth, but If i hold the wheel back fully to 100%, the board starts slowing down and almost immediatelly cuts off power and the braking is immediately reduced by 60-80% and if i keep holding down the brake, it somewhat starts braking again until it cuts back power again and its overall VERY jerky. The brake issue occurs at low speeds and high speeds, for the acceleration issue I havent tested pushed over 70% throttle, when I reach the speed limit of it because If i experience jerkyness, i will fall.
I’ve struggled with this for over a year now and I am downright mad after not being able to figure it out on my own, nor find a topic with a solution that worked for me and thus I am resorting to pleading for help.
Its a bit hard to put into words or I am just frustrated and impatient at this point but Here are some graphs that will hopefully help you visualise :
Progression history of the issue throughout hardware
First I had 2x4.12 50A Vescs with 140KV motors 14T / 36T gear ratio - wasn’t an issue
Then i changed the gear ratio to 16T / 36T and the issue became present after 85% brake power so I just avoided hitting the brakes hard.
Then i switched to 18T / 36T 190KV motors and the issue became more exaggerated and showed up during acceleration as well. I modified some settings/reduced them quite a bit and got it to work somewhat without much issue but power was substantially lower than expected.
Then I bought a different esc - an FS “4.20” 100A combined still and the issue popped up again but this time I can’t get it to work at all to be any amount of smooth.
What I’ve tried : literally everything
I am not sure if its worth bothering writing out my settings but the most basic settings are :
Motor current max : 65A (tried range 20-65)
Motor current max barke : -65A (tried range 20-65)
Absolute maximum current : 140 (tried range 80-200)
Battery Current Max : 40A (tried range 20-40)
Battery Current Max Regen : -15A (tried range 0-25)
Duty Cycle : 85% (tried range 70-100)
Control source : UART
Motor Type : FOC (tried BLDC)
Sensors : Hall (tried HFI / Sensorless / Hall)
The only thing that I am thinking of is that when I went through the motor wizard, i still had the belts and wheels on, just the board on its back (when setting up the new esc). Thats the only thing I can think of.
I tried looking at multiple logs but I can’t identify the issue myself. For some reason, when i click on the graph to select a point in time, the values on the side and the values on the graph do not match and the difference seems to be 1-2 seconds on my software.
Here is one with the settings above 2023-02-24_18-19-42.csv (967.9 KB)
Electronics :
Battery : 10s3p Molicel p42a battery
BMS : Bestech d596 80A BMS
ESC : Flipsky 4.20 Smart 100A Cont. 200A Peak. ESC with heatsink
Gear ratio : 18T/36T Gear ratio with fairly loose but not too loose belts
Motors : Flipsky 190KV 2350W 6354 BH BLDC Motors
Remote : Flipsky VX1 remote connected with UART
Firmware : 6.00 on 410
Hmm I would have guessed your PPM settings were wrong, but you say you’re using the remote in UART mode
Maybe opening up vesc tool and seeing what values the remote gives beyond 80% throttle might bring something up, if the remote were at fault
Is this a dual drive setup? If yes, then on acceleration drawing 40 + 40 = 80A might be hitting your BMS limit and it could be causing issues. You could test this by temporarily bypassing the BMS.
It could also be that your motor current is way too high for vesc 4 hardware, but you said you tried just 20A, and that should have been well within limits…
Using old hardware does have me wondering if it’s just the ESC that’s the problem; and it can’t handle high duty cycles.
If you were to disable slow ABS current limit, maybe the ESC will start throwing faults? Have you checked for any faults / gotten any btw?
I had this exact same issue on an adc throttle. I chased the throttle for a while but it turned out to be a motor detection issue.
I upped my switching frequency to 30khz and did the detection using the 2kg outrunner setting without resetting defaults.
Ran great after that.
Throttle controls current, so maybe try lowering the current to see if it’s the remote or the current level. Then you can figure out if the high current is causing interference or if the motor parameters are off enough that the issue arrises then.
If the problem remains, then it’s probably the remote
No, as I don’t have one. For the PPM mode, it needs to be manually soldered and the wires are really tiny, I am not sure if it is a possibility for me to do.
UART doesn’t show remote metrics in the app
I thought of this and deliberately tried 38 and 39 amps as well, but from the logs, the battery amps are always within limits and the issue occurs even at lower battery amps
Not sure what high duty cycles is.
No faults, only when i pushed the battery regen to -25A and I quickly turned it back down not to fry the mosfets Im not sure what ABS Current Limit does so I haven’t exactly fiddled with it but might be worth a shot.
I know which cables these are, but I am not sure what you are suggesting. Shield them as in wrap them in alum. foil or sth?
The wires connecting the remote receiver are to the side of the motor wires and they are not overlapping in any way. The remote receiver itself is underneath the motor phase wires though.
Will check this out, not sure what it is honestly.
Final note : I doesn’t make sense for it to be the remote in my mind as for the first year i haven’t had practically any issues and recently before I got the new esc I was full throttle accelerating with no issues, only the breaking had this issue and only at the end. Miiiight be the remote but…
P.S. Somehow the on/off button stopped switching off the ESC… -.- Any idea if there is some setting that i might’ve changed by accident to cause this or did i melt something inside?
My bad; it’s not duty cycle causing your issues, it’s giving more throttle.
Please move the receiver and its wires as far away from the phase wires as possible lol
But sounds like jaykup might be right about it being a motor detection issue; and high saliency or something messing things up as you give more throttle. His suggestion on using a different switching frequency and redetecting might work. IMHO issues like this come with the territory of using older vesc hardware
If this is Maximum Duty Cycle, do not exceed 95% on those devices. If this is “Duty Cycle Current Limit Start” then it’s dangerous to call it Duty Cycle because it leads to confusion later.
There are many settings with very similar names, and it’s NOT okay to confuse them.
From the logs… I couldn’t detect a specific pattern but one thing that stuck out to me was that the motors peaked at about 90ish amps which is within spec and then they fell down rapidly. I noticed this in a couple of logs but didn’t think much of it.
Today i went out and tried some things, I changed the placement of the controller receiver to be like 20cm away from the motor phase wires and i ran the motor detection on the 2kg motor preset. It set motor current max to something ridiculous like 100A but I tried it for like 20meters just to see - the issue was even more apparent/prominent. I turned down the amps back down til I reached a small parking lot and played a little bit with the settings. I tested out Motor Current Max at 45A and Braking Current Max at 35A. It seems to work pretty well :? Full throttle does not cause jitter in the acceleration on flat ground, but on a 15ish degree slope, full throttle DOES cause jitter when I reach a point where max amps would be used. Braking at -35amps max seems to be okay although it shows veeery slight jitter at the end as well.
I don’t know what and why is causing this honestly, but it doesn’t make sense to be from :
Motor detection : Ran many times, different settings etc, issue is present.
The remote : with different settings the issue is present in varying degrees
The signal : it is stable, there aren’t cutouts
The motors : I tried two sets of motors and they have had this issue (sensored/sensorless)
The esc : i’ve tried different ESC’s and the issue is still present.
What Im thinking : Either the esc hardware is F’d and 4.12/“4.20” (which is actually 4.10) just can’t handle the motors pushing more than 80-90 amps and it ramps it down, or it has something to do with the Bestech D596 bms which is 80A tops. From the logs it doesn’t reach the set battery limits (which i always set to 40A per motor), but at this point, it is shenanigans.
Im not sure what ABS Current Limit does so I haven’t exactly fiddled with it but might be worth a shot.