FOCBOX UNITY $299 | R-SPEC DRIVE KIT $588

Throttle and braking issues. Been fine for a week, now I have a problem


#1

So, hopped on today and it felt different. Could feel a notice in acceleration and braking they were both much slower. Came home and saw this was happening https://youtu.be/vo11NvobB4o

I just checked and there was one connection that was loose. I since then fixed it. But the issue persists. Any ideas?

Just checked the connection to the receiver and it seems okay. What do i check next?


#2

When I go to brake, the VESCS that consistently does not brake, the left wheel in the video, it has an LED that blinks red between the blue and the green LED


#3

huh, post your settings, seems to be something is off


#4

I will post them as soon as I get home. I’m in the middle of class now.


#5

great place to edit a video haha


#6

Looks like an ABS overcurrent situation sending the vesc into fault. Get eyes on the VESC and see if it flashes 3 times when this happens. May be a settings issue or you could need some service. Have you used FOC in the past? No worries if you did, we will still provide service even though we do not recommend using that function of the VESC.


#7

I took that video when I got home just before I left for class, just posted the url when I got here.


#8

I’ll have to check when I get home again, I can’t recall how many times it blinked. And no I don’t use FOC, both VESCs are exact same settings. I’ve really been riding it every day around campus for a week straight. Maybe like 7 miles a day.


#9

Blasto, @chaka

These are the settings I posted in the original post and haven’t changed it since. I grabbed this off the original post I made about the build so I don’t have access to the rest of it until I get back.

Just thought about something. My BMS supports charging up to 20amps so should my regen braking be 10 or less per VESC?


#10

set your maximum input back to 57V

when braking, your are hitting your upper limit, the vesc thinks it needs to protect itself and “shutsdown”


#11

Okay, i will adjust this when I get home. But if this is the case how come I have 2 VESCs with the exact same settings gs but only one just started acting up?


#12

in the video both of them seem to have this weird behaviour, just not at the same time


#13

That’s a good point though it seems to be one more than the other. Let me try this when I get home in 2 hours and I’ll update you on if this resolved the issue. So just follow up question, what would have triggeted this? Could one loose bullet connector have caused this while trying to brake? Just trying to understand the root cause so I can prevent it from happening again going forward.


#14

it is just a bad setting, should not touch this setting, it won’t damage anything, just give false errors


#15

But my confusion is why did it take a week for this bad setting to manifest itself? That’s kinda what I’m confused about. @chaka can you provide some clarification on this? I’ll be changing the max input voltage back up to 57V, but I’m just trying to understand why this wasn’t an issue from the get go?


#16

did you freshly charge your batteries?


#17

Yes. Charged it last night to full. Just hopped on this morning to head to a meeting and that’s when I noticed. But there were issues with acceleration as well, which was probably due to the loose bullet connector. But then I noticed the braking which I knew could be due to just being charged but again. This whole week I haven’t had any issues with breaking with a full battery so that’s what made me think there was something wrong. Them I went home and made that video


#18

Your cells could be responding to use. If it is a small pack and you have been driving too much regen current they could have degraded enough to rise in voltage much faster than when new. Repeated faults could have also corrupted the firmware. A fresh upload using the bootloader can fix it if that is the case.


#19

It’s a 8S6P pack using Samsung 25R 18650 cells. So when I get back, if raising the input voltage back to 57V doesn’t solve the issue I’d have to reset the firmware? Is that the same as flashing the firmware? Because I heard you can mess that up and render the VESCs useless sof I’m hesitant to do that.

Not sure if it makes a difference @Blasto but the pack is fully charged at 33.6, charged up 33.4 last night. After my trip to the meeting goes and back its currently sitting at 32.6 so it’s not at full.


#20

You should also lower you regen to -7 to -10 per vesc. when you snap the brakes like you were in the video you are probably peaking around 80 amps of regen. The limits on the vesc take a few milliseconds to respond since everything is relying on the processing speed of the stm chip.