BBS** Settings/Pedal Assist/Stop Decay *Excellent Motor Refinement *

[voidedwarranty]

Sorry about that @Gionnirocket , noticed after I posted it was wrong thread.

I've done that too. As a matter of fact I don't even know which thread I am currently in

 

[K PierreR]

I've gotten so use to Up/Down shifting my PAS that I do it second nature now. My terrain is constantly changing and I'm always ready to adapt if I want to stay fluid. I think it adds a layer of enjoyment to the ride as down shifting into a tight turn does while driving. Keep in mind I'm using a incremental Speed increase in PAS levels not Current.


Curious... Do you plan on implementing a higher Stop Decay with the other bikes you manage?
If you have already, what was the consensus?

I use the gearing to select what cadence I want and the PAS levels to select what speed I can maintain. For me, its automatic and I use both about equally.

I do plan on trying these settings on the other bikes that I maintain.

 

[AHicks]

Couldn't agree more. Being that most of my settings have to be hinged around my rear hub, it really changes the whole philosophy of how the motor needs to work in order to play nice with my drivetrain, while also getting what I want out of it.

Fine-tuning the programming is so important. A decent amount of our settings are so different, yet we both end up with smooth engagements for our given applications.

Now consider that the new motors are equipped with the CANBUS, and you will easily see how Bafang has shot itself in the foot with every new motor sold....

Can't last. Something has to give....

 

[voidedwarranty]

Now consider that the new motors are equipped with the CANBUS, and you will easily see how Bafang has shot itself in the foot with every new motor sold....

Can't last. Something has to give....

That really depends. It's no secret that Bafang was furious about their programming getting cracked open like an egg and made available to everyone.

I'm sure in their eyes, getting back some control and "locking" their customers out is exactly what they wanted. It's not like there are many other companies pumping out 160nm kit ready mid-drives they have to compete against.

With that all being said, CANBus IS programmable. It will just take a bit of time to crack. It actually allows for so much more functionality than UART does once it is opened up. CANBus is a GOOD thing in the long run. Be patient, I promise you good things will come of this.

 

[Gionnirocket]

Sorry about that @Gionnirocket , noticed after I posted it was wrong thread.

No worries at all
It's still good information

 

[AHicks]

That really depends. It's no secret that Bafang was furious about their programming getting cracked open like an egg and made available to everyone.

I'm sure in their eyes, getting back some control and "locking" their customers out is exactly what they wanted. It's not like there are many other companies pumping out 160nm kit ready mid-drives they have to compete against.

With that all being said, CANBus IS programmable. It will just take a bit of time to crack. It actually allows for so much more functionality than UART does once it is opened up. CANBus is a GOOD thing in the long run. Be patient, I promise you good things will come of this.

Now consider that the new motors are equipped with the CANBUS, and you will easily see how Bafang has shot itself in the foot with every new motor sold....

Can't last. Something has to give....

By "shot itself in the foot", I meant from the user's perspective. I could give a damn about Bafang. They could still be selling it as one of the better motors available - if they had left it as a UART!

Also, when I said "something has to give", it was with the hope that we'll be able to adjust the CANBUS motors one day - including the M600...

 

[smorgasbord]

It doesn't affect the cutout at all from the brakes or gear sensors, but when the motor hits my set limit it spins down GRADUALLY so there is no drag from instant cutout. Then when the motor re-engages there isn't a sudden jerk. Everything is buttery smooth.

Intellectually, this makes sense - applying more current when some current still being applied should feel smoother than starting up from no current applied, especially if the controller is looking at wheel rpm to determine if "Slow Start Mode" should be applied. Going back to the "sacred" diagram, here's what a stop-start pedaling event might look like with a small Stop Decay and assuming that since the bike is still coasting that wheel rpm is high enough that Slow Start Mode isn't being applied:

When pedaling stops, current stays high during Time To Stop (aka Penov's Stop Delay), and then current starts some kind of non-linear ramp to zero, and then pedaling starts again, but since the wheel rpm isn't "slow" power ramps up pretty quickly (might depend on how quickly your pedaling cadence ramps up) and it feels abrupt.

Now, with the same pedaling stop-start timing, here's what it might look like with a large Stop Decay:

Sorry for my bad Photoshop skills. The idea is that the longer Stop Decay time means that current doesn't get all the way to zero before the next pedaling action calls for more current. And that should feel smoother.

Now, I don't think any of us know the curve shapes involved in decay or acceleration or re-acceleration, and we don't know the "slow" cut-off that is used by Slow Start Mode, nor how the transition from current decay to current apply happens, but the longer Stop Decay might result in a smoother feel. And if Slow Start Mode would apply in the re-start of pedaling then the ramp up would be even smoother.

The curious part is why some feel a larger Stop Decay doesn't result in noticeably more motor run-on after pedaling stops for long periods of time. One thought is that Stop Decay is, as @circuitsmith drew, some kind of non-linear curve, perhaps exponential, in that most of the current drop off occurs soon after pedaling stops, and that the rate of drop-off itself slows down as the Stop Decay period comes to a close. With a, say, 1.5 second Stop Decay, you might see the current drop 50% within the first half second and the last 50% during the last full second. So in terms of perception, it feels like the motor hasn't run-on since it's dropped so much so quickly, but there's still enough current that when you start-up again it's smoother to ramp up from some percentage of current than from completely none.

At any rate, the behaviors experienced in this thread do not necessarily conflict with the widely accepted definition of Stop Decay. That includes that Stop Decay might affect acceleration, since that acceleration might be occurring within the Stop Decay time period.

It would be interesting to perform some timing tests to see if re-start of pedaling delayed to well after Time Of Stop + Stop Decay has passed is still smoother with large Stop Decays. Separately, has anyone determined when Slow Start Mode is and isn't applied? What is the controller's definition of a "slow start"?

 

[circuitsmith]

One thought is that Stop Decay is, as @circuitsmith drew, some kind of non-linear curve, perhaps exponential, in that most of the current drop off occurs soon after pedaling stops, and that the rate of drop-off itself slows down as the Stop Decay period comes to a close.

FYI, I didn't draw the diagram. It came with v2.2b of the Penov program, which I've attached.

 

[Gionnirocket]

Where you've gone wrong is the smoothness gained and mostly discussed is during cruising and with constant pedaling and hence the motor under constant load.
Then on the acceleration it's most notably smoother from a dead stop or where there's been no pedaling for more than just a few seconds.... so there's that.

That said, read my OP... Your diagram is exactly what I described... I just didn't need picture and it's the motor under constant load, not between pedal stops. Maybe the drop off is 75%then 25%... Or maybe there is no drop off controlled by this. The eggrider data shows no difference between a setting of 0 to 250.

Did anyone experience the motor run on that you warn us all of?
Or was it that they too found it beneficial to varying degrees and with no downside...
Is it imperceivable? or maybe you're mistaken.

 

[Gionnirocket]

FYI, I didn't draw the diagram. It came with v2.2b of the Penov program, which I've attached.

Sure!
Post while I'm typing.

 

[m@Robertson]

errr... I hate to interrupt you two love birds, but I thought I would point out that Stefan Penov has not been involved with the Bafang Config Tool for quite some time. The v2.2 version (and the graph) was written by 'Laurent V.' Since he wrote first 2.2a and then 2.2b in rapid succession in 2019, I am guessing he's not actively developing it.

Logiciel de Configuration Bafang BBS version améliorée

Vélo à Assistance Electrique motorisation et moteur BAFANG logiciel de programmation des contrôleurs Bafang BBS

blitip.blogspot.com

In other news, I decided to try a stop decay of 1100 ms this afternoon (up from zero ms) and my bike didn't turn into a Model T1000. So we'll see what I can figure out tomorrow in terms of different behavior. Initial and thoroughly tentative impression is its doing what it is purported to do in the graph, but cranking it up like that is not any sort of detriment to operation. It seems to make for a smoother letdown when I stop pedaling and (again this is tentative as only a couple circles around the block in my slippers not my riding cleats) there is a definite audible motor sound in addition to seeing the chainring spin. I was riding it on very strong PAS while also in a very low gear to try and emphasize the motor spinning without going so fast I started losing ability to trace sound due to wind noise. Also I shut off my front motor so I'm not getting any cross-pollination.

 

[Gionnirocket]

errr... I hate to interrupt you two love birds, but I thought I would point out that Stefan Penov has not been involved with the Bafang Config Tool for quite some time. The v2.2 version (and the graph) was written by 'Laurent V.' Since he wrote first 2.2a and then 2.2b in rapid succession in 2019, I am guessing he's not actively developing it.

Logiciel de Configuration Bafang BBS version améliorée

Vélo à Assistance Electrique motorisation et moteur BAFANG logiciel de programmation des contrôleurs Bafang BBS

blitip.blogspot.com

In other news, I decided to try a stop decay of 1100 ms this afternoon (up from zero ms) and my bike didn't turn into a Model T1000. So we'll see what I can figure out tomorrow in terms of different behavandior. Initial and thoroughly tentative impression is its doing what it is purported to do in the graph, but cranking it up like that is not any sort of detriment to operation. It seems to make for a smoother letdown when I stop pedaling and (again this is tentative as only a couple circles around the block in my slippers not my riding cleats) there is a definite audible motor sound in addition to seeing the chainring spin. I was riding it on very strong PAS while also in a very low gear to try and emphasize the motor spinning without going so fast I started losing ability to trace sound due to wind noise. Also I shut off my front motor so I'm not getting any cross-pollination.

Thank you sir.
And yes I too had realized Penoff wasn't involved in this latest version of the software but since I hadn't taken a screen shot of the info I didn't want to post the details without pictures as some seem to struggle without them.

My contention is this...
If this setting set to >100 (=1s =1000ms for those who struggle with math and need pictures) affects acceleration and cruising smoothness (motor under constant load) then it's initial description can not be correct as it is doing more than being in affect only after pedal stop. Does some artifact of it perhaps cause a near imperceivable motor run on, maybe. But I and others don't perceive it and it's definitely not the motor run on that has been fear monger'd by every internet parrot and wanna_be influencer. I and others have set it as high as 250 and the motor run on if any was no more than the setting of 100.

Now set Stop Delay to just 20 and the motor run on is more than just noticeable and something to be very aware of.

One more recent observation is that this may be more relevant to the BBS02B as those posting the most positive comments were using this motor. The BBSHD comments have been somewhat mixed and it's hard to determine if it's acting differently or just not their preference.

Thanks again for taking the time as you actually own a BBS*

 

[Gionnirocket]

SPECIALIZED TOOTHPICK.

Do you ever sleep!?!?

 

[Gionnirocket]

I guess I'll just have to break my post down into short chunks for @Gionnirocket to digest:

@Gionnirocket wrote:
"It [Stop Decay] does not affect the motor stopping time at all when you stop pedaling. I feel that it is misnamed and definitely mis_described with a high degree of certainty."

But he also wrote:
"Now set Stop Delay to just 20 and the motor run on is more than just noticeable..."

These are contradictory statements he should attempt to clarify instead of insulting me.

I'm sorry but I really didn't know what to say to that and that's why you didn't receive a reply.
Let me try a picture.

 

[Gionnirocket]

Let me elaborate on my contentions...
First let me say that I have nothing but respect and admiration for the founding father, the 49 page bible and the Hackers Guide, Penoff, etc....
Without them we'd still be in the dark. I have no delusion that I am smarter than any of them.
What I do have an issue with is those that think that they are infallible and all others after them have nothing to contribute.
It's much easier to build on knowledge with a firm foundation and as more sets of eyes focus on a problem.

So i think a few things may be at play here...
Bafang has multiple firmwares for their different motors in the BBS series and what might be true for one in particular might not be true for all.
Then...
The initial description of this setting is that it add RUN ON and smooths the deceleration curve AFTER PEDAL STOP.
Statements such as this...
Ken Taylor says in part:
The setting Stop Decay(x10ms) on the PAS tab I found to affect run on when testing on the Kurt Kinetic rolling road. I tried a large value, I forget the upper limit but there is one, and it ran on upwards of a second (I forget exactly) but it seemed a long time. Run on time also seemed inconsistent but I didn't investigate why.
I didn't want run on because if you are drafting and the gap starts to reduce you need to be able to stop human and motor power as fast as possible to avoid collision and you can't use the brakes or the person behind is likely to collide with you. I set this value at 0, which was how it was supplied from EM3EV and as far as I can tell there is no run on.

I'm sorry but that doesn't seem to be a rock solid method of testing.

And as we all know... repeat something enough times and it becomes true, especially on the internet. Not saying that is what happened, but some variation of that is possible.
And now because of this initial belief, no one has bothered to experiment with settings, especially above 100 (1000ms) where I feel the benefits described live.
I and other's have found that a setting above 100 is indeed very noticeably effective at smoothing the acceleration curve and cruising under motor load and these do not occur after you have stopped pedaling. The ON/OFF feel of the cadence sensor controlled motor that most BBS users complain about is drastically reduced. And I do need to add that there is no difference in motor run on with a Stop Decay setting of 0 through 2500 on my BBS02B.

In conclusion I'll say this.
I have no data to support this.
But I do have over 10000mi on my BBS02B and I clearly know the difference when using this setting as they are not subtle and it was a game changer for me.
I feel sorry for those that won't try it due to fear or if their firmware (if even applicable) doesn't allow them to experience the benefits.
This said... I have zero desire to be an internet influencer or some EBR Superstar. Do it, don't do it I really don't give a flóck. I'm just sharing my experience and some have benefited.
Those on a crusade to shoot it down without data and/or experience can...

104 knots... Rotate.