VESC Braking (release)

@dogeatgod

It could be either. I really notice it at slow speed when i push the trigger too far. I think of “hard” braking as a combination of trigger extremity and trigger movement speed. So, braking too hard can force a reboot, and braking too fast can also do it.

It takes about 1-2 seconds to reboot and then come back to life. Not very long, but long enough that it can cause trouble during a ride!

I mean that the board might stop\reduce speed while my body is still accelerating, so I fall off of it. This was more due to my own bad riding… I was getting used to the braking and applied it too hard.

Thanks @elkick that’s very helpful! I’ll try -15 after I update to 2.16.

Sounds like this is what was happening to me

Yeah, and during the reboot period it’s a very bad idea to play around with the trigger! If the VESC’s coming back it continues exactly where your trigger is: if you’re on full throttle in this very moment (or full break) it will exactly apply that!

And believe me, that’s beyond your skating skills! Happened to me today and was no fun trying to outsmart physical laws. :wink:

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LOL. As you probably realize by now, skaters are constantly nursing road rash on one body part or other :sunglasses:

I wish my board could toss me off.

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@elkick @trbt555 @dogeatgod Here’s something interesting. Mellow advertises that their braking system “still works when you are fully charged. Whereas the brakes of a lot of the existing rides actually switch off at that point. Take that for a killer feature.”

Holy shit! They are right about that! I’m almost tempted to just turn off regen braking. That would solve the problem for sure.

Well, they are asking a good uplift for that feature compared with our standard costs, if they remain with those 1.600€ per kit. I don’t trust their distance claims though. And they are located in my home town, how comes that I never see them testing their stuff? Would like to compare their sets with mine…

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@elkick agreed! The cost seems really high. Although I’ll admit that I like the concept quite a lot and I think it’s way cooler that buying a standard mass-market eskate. The swappable frame\battery kit is a very cool idea. I suppose with a standard battery it’s not that hard to write some code into the ESC that limits charging once a full charge is present.

This sounds like another idea to add to the feature request for VESC!

Wow - that’s a statement, a known problem then.

If the regen settings or regen on a full battery is proven to cause brake failure I’m glad I’m not selling these commercially - sounds like just a matter of time before that feature is confirmed.

I came close to leaving my teeth in a car bonnet.

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@dogeatgod Right, this was my point… it’s a known problem. I wonder what all of those lecdec\backfire clones do to prevent this issue; they all have regen (or claim to).

Wow, thanks for the link. Those products look really slick. I like the idea of the swappable battery pack.

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@trbt555 yes, and they advertise as “water and dust proof” with video of them drive through mud puddles. That is extremely cool, although I sthink that riding on wet roads is a terrible idea in terms of safety.

I think there are some things to clarify with regen braking and VESC, normally it should not go offline at all while breaking. And if it does, I doubt it’s related to regen and full batteries. First of all, the regen effect is around 10-15% only and even though the VESC is regen capable, it doesn’t apply for speeds below a certain ERPM value.

These are Benjamins remarks about that: "Max ERPM at full brake in CC mode” is the highest RPM at which applying full brake by shorting all the motor windings is allowed. Setting this value too high can cause much mechanical stress in some circumstances.

So, conventional braking is implemented in the VESC. Assumption: if regen braking fails, it should switch to “conventional” braking, but not reboot the VESC.

Additionally, it’s easy to avoid the problem by limiting the BMS on lion batteries to 4.1V for charging. This leaves enough room for regen braking even down a steep hill with “full” batteries.

I think that’s exactly what mellow uses to avoid this.

thanks @elkick, but I think that the issue I’m having is with an incoming current that is too high while braking, as opposed to hitting the battery’s capacity… the same issue occurs for me even when the battery is depleted.

I that read that mellow use a capacitor to dump the access regen to then use it again at next take off.

But what has already been said is true, regen will not reset your vesc, but over voltage will.

I don’t know if any of you are setting your voltage settings or not but if you set your max to the exact same as your battery pack then if there is any spike while braking then you will have a problem.

Are you sure your vesc is rebooting? This could actually be a drv fault for a split few seconds, the red light flashes you can do any thing then every thing comes good. In a lot of HW 4.10 or 4.11 this has been a problem and the solution was adding a extra cap on pad c18 I think. @chaka does this but now there is HW 4.12 that fixes it.

One last thing. I know it is said that changing batt min will reduce braking at speed and motor min will reduce braking at stop and low speed, but I feel there is a big cross over that I discovered while testing my hub motors, braking would just throw me off because it was instant. it is best to try and lower motor min to like -20 and batt min to -10 then go for a test ride if it fixes the cut out then move them up as needed.

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I seem to have rectified my problem but whatever caused the brake failure has not been clearly identified.

If it is voltage spike then adjusting settings should allow the problem to be recreated - before doing this, could it damage either the VESC/battery or would protection (drop out) kick in?

Not sure if VESC is rebooting – it was only happening under load and it’s not possible to view the VESC whilst driving on my set up. VESC is 4.10 so could be drv fault.

My earlier ESC had “conventional” braking only and never had the brakes drop out.

I hope that root cause can be identified swiftly and knowledge shared to improve performance or prevent an undesirable event.

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