Bafang Ultra (and BBSxx) Tuning

[AHicks]

I agree that 28A vs 30A isn't such a big deal but it makes me wonder if my motor is being "neutered". I mean if it's a 48V controller is it getting anything past that? Because 48V x 28A is 1344w which would explain why my display's power meter always comes up short of the 1500w that is advertised.

The change from throttle "speed" to "current" is awesome. Throttle is so much more controllable. I find it weird though that in biktrix own help guide they have these mixed up. They claim the speed setting is for a "gas pedal like response" while current is "on/off switch".

Maybe I'm just more annoyed about this whole controller thing because of the issues I am still having with the brakes but thats another topic for another thread

Controllers, for the most part, are about amperage control. Volts, maybe not so much.

Yup, now you can understand more fully the difference between speed based PAS and power based PAS. Night and day difference, and that applies to hub powered as much as it applies to a mid drive. Power based PAS is a really big deal. My bet is that will become more and more commonly seen. It's the same hardware. The ONLY difference is in the software....

Brakes squealing? Do you have a note on that going somewhere?

 

[voidedwarranty]

Controllers, for the most part, are about amperage control. Volts, maybe not so much.

Yup, now you can understand more fully the difference between speed based PAS and power based PAS. Night and day difference, and that applies to hub powered as much as it applies to a mid drive. Power based PAS is a really big deal. My bet is that will become more and more commonly seen. It's the same hardware. The ONLY difference is in the software....

Brakes squealing? Do you have a note on that going somewhere?

I've posted about it on another thread, but since that post it has gotten more nuanced. Close inspection looks like the brake pads ride above the top of the rotor intermittently due to the design of the rotors. It has that wavy pattern on the end of the rotor so the pads make full contact when the waves are at their high point but when they dip down the pads are now overhanging the top of the rotor. This is causing a deep groove in one of the pads and an awful noise I'm currently working through it with Biktrix support.

 

[m@Robertson]

The change from throttle "speed" to "current" is awesome. Throttle is so much more controllable. I find it weird though that in biktrix own help guide they have these mixed up. They claim the speed setting is for a "gas pedal like response" while current is "on/off switch".

On the subject of throttle settings, do you have your start and stop set at 11 and 42 vs the usual 11 and 35? The wider range gives a longer scale to the throttle curve and lets you have much more granular control across the throw of your throttle lever, or grip rotation. I read about this originally in Karl Gesslein's BBSxx programming article and once I tried it, its been my default ever since.

 

[Gionnirocket]

On the subject of throttle settings, do you have your start and stop set at 11 and 42 vs the usual 11 and 35? The wider range gives a longer scale to the throttle curve and lets you have much more granular control across the throw of your throttle lever, or grip rotation. I read about this originally in Karl Gesslein's BBSxx programming article and once I tried it, its been my default ever since.

My Half_twist throttle works well with a range of 9 - 38.
11 gave me no response for the first quarter inch of rotation

 

[voidedwarranty]

On the subject of throttle settings, do you have your start and stop set at 11 and 42 vs the usual 11 and 35? The wider range gives a longer scale to the throttle curve and lets you have much more granular control across the throw of your throttle lever, or grip rotation. I read about this originally in Karl Gesslein's BBSxx programming article and once I tried it, its been my default ever since.

I set to 11-40

 

[m@Robertson]

My Half_twist throttle works well with a range of 9 - 38.
11 gave me no response for the first quarter inch of rotation

Thats interesting. I thought 11 was the floor. I'll have to give 9 a try. Right now I can bleed in 200w or so without too much difficulty.

 

[voidedwarranty]

Thats interesting. I thought 11 was the floor. I'll have to give 9 a try. Right now I can bleed in 200w or so without too much difficulty.

It depends on the throttle. Some throttles run a different voltage range. There is a way to check this with a multimeter

 

[Gionnirocket]

Thats interesting. I thought 11 was the floor. I'll have to give 9 a try. Right now I can bleed in 200w or so without too much difficulty.

Voided is correct about it depending on the throttle. The Half_twist seems to operate at a lower range than the thumb and full_twist that I have tried. And I'm sure that might change as well by manufacturer.
I also tried 10 which cut the dead zone down to 1/8 inch and 8 which returned a Throttle error
I too can feather in a minimal amount and slowly ramp up to full output

 

[m@Robertson]

It depends on the throttle. Some throttles run a different voltage range. There is a way to check this with a multimeter

I tried 9 on my Surly and it worked fine. I am using the generic ambidextrous Bafang/clone universal paddle-wheel throttle. Not sure if I will notice a difference but a wider range is better I should think.

 

[AHicks]

I tried 9 on my Surly and it worked fine. I am using the generic ambidextrous Bafang/clone universal paddle-wheel throttle. Not sure if I will notice a difference but a wider range is better I should think.

This just reinforces the fact that customizing your settings to suit yourself is a great plan/idea. I opened my throttle range up as far as possible and noticed the difference right away.

And while I'm at it, the idea you wrote about regarding the motor not shutting down immediately when you stop pedaling, to allow it to finish a shift for you, is a stroke of genius. Prior to reading that, I had NO use for the motor running on. It just didn't make sense, but it does now! It's that kind of thinking/sharing/explaining of new ideas that makes forums like this so fun! Thank You Again! -Al

 

[m@Robertson]

And while I'm at it, the idea you wrote about regarding the motor not shutting down immediately when you stop pedaling, to allow it to finish a shift for you, is a stroke of genius. Prior to reading that, I had NO use for the motor running on. It just didn't make sense, but it does now! It's that kind of thinking/sharing/explaining of new ideas that makes forums like this so fun! Thank You Again! -Al

Glad I could help! Want to make sure you spotted the fact I also have the motor shutting down sorta kinda asap in my settings. I'm just using that barest bit of motion left. I *have* done it with factory settings which seem to last ... for. ever. but not happy with the lonnnnng lag after killing assist or throttle except in that one case with shifting.

But absolutely... there is no such thing as a perfect set of settings. We're all different and if we can better figure out what these often-opaque settings do, we're better able to figure out for ourselves what we like best.

When I switched the Surly's chainring over the weekend, I checked how much motion it needs to shift with the SRAM drivetrain and its less than I thought. depends on the cog size of course but its only a 1/4 cog turn on the biggies. Less on the smaller ones.

 

[Gionnirocket]

Glad I could help! Want to make sure you spotted the fact I also have the motor shutting down sorta kinda asap in my settings. I'm just using that barest bit of motion left. I *have* done it with factory settings which seem to last ... for. ever. but not happy with the lonnnnng lag after killing assist or throttle except in that one case with shifting.

But absolutely... there is no such thing as a perfect set of settings. We're all different and if we can better figure out what these often-opaque settings do, we're better able to figure out for ourselves what we like best.

When I switched the Surly's chainring over the weekend, I checked how much motion it needs to shift with the SRAM drivetrain and its less than I thought. depends on the cog size of course but its only a 1/4 cog turn on the biggies. Less on the smaller ones.

So true....
And funny I went in the somewhat other direction as far as addressing shifting. I have the start delay set to 5 as that gives me a quarter crank on a 44t chainring and more than enough chain scroll for the bike to shift before motor engagement. This works well if you have to break unexpectedly or stopping while tired. On the BBS02B I do find the stock 25 setting for stop delay a bit long... But lowering it affects other motor smoothness factors and going too low actually f*cks PAS operation all together.
On the throttle you have to see if the lower setting actually provides a wider range. I did so by setting the bike up on a stand and marking throttle engagement as I slowly moved the handle/lever. On the Half_twist the difference was easily seen. I hadn't noticed any delay in the other throttles to warrant tinkering. Perhaps in theory lowering the number without reason could shorten the range. But as many of us have stated before.. these often opaque settings take a bit of tinkering.

 

[tomjasz]

It’s probably late in the game but I hope readers here realize that experimental settings, without reviewing available.el files can brick a controller or trash a motor. Please, use common sense and follow the readily available parameter suggestions. I get a call every month from experiment failed users.

 

[Gionnirocket]

It’s probably late in the game but I hope readers here realize that experimental settings, without reviewing available.el files can brick a controller or trash a motor. Please, use common sense and follow the readily available parameter suggestions. I get a call every month from experiment failed users.

I have to disagree with you somewhat here... Please forgive me Santo
Most of the el files I've seen seem to be geared towards the younger speed performance crowd.
Most of the discussion here has leaned towards the older want some assistance during exercise crowd.
Add to that... that there are so many variables on how the motor feels and what you are trying to achieve that I've reached much better results by experimentation then accepting someone else's idea of the perfect el file.

 

[tomjasz]

I have to disagree with you somewhat here... Please forgive me Santo
Most of the el files I've seen seem to be geared towards the younger speed performance crowd.
Most of the discussion here has leaned towards the older want some assistance during exercise crowd.
Add to that... that there are so many variables on how the motor feels and what you are trying to achieve that I've reached much better results by experimentation then accepting someone else's idea of the perfect el file.

Regardless of your experience and success, I’ve had at least a dozen customers since 2015 that “screwed the pooch”. I’m happy your experience has been trouble free. It may be due to your due diligence. Something that can be lacking in the forum educated n00bs.

 

[Gionnirocket]

Regardless of your experience and success, I’ve had at least a dozen customers since 2015 that “screwed the pooch”. I’m happy your experience has been trouble free. It may be due to your due diligence. Something that can be lacking in the forum educated n00bs.

I have no doubt that people are expecting too much from these motors and/or not using common sense and/or lack the experience when applying the motor ratings to their use. Not trying to bash anyone but the Luna crowd comes to mind. Hi performance inherently has more durability issues and requires more than typical maintenance and repair. Nothing wrong with that if you are willing to pay for it... and it can be fun for a while.
My experience with just about everything is using it at 60- 80% of its rating will result in a very reliable product.
Using it at 90-110% of its rating will leave you buying a new one in short time.

 

[tomjasz]

Nothing wrong with that if you are willing to pay for it... and it can be fun for a while.

 

[m@Robertson]

I don't do it anymore, but something I did early on and something I put in my BBSHD programming guide for those noobs: Take a freaking picture of your settings on your phone - every screen - before you touch anything. If you brick it, you have a way to bet back to Square 1.

 

[Gionnirocket]

Hey Al
So since you started tweaking the Ultra... what improvements or changes have you made to the controller?
Any improvements in efficiency or range?

Did you happen to take screen shots of the stock parameters?

 

[AHicks]

Other than the throttle mods to tame it down a bit from a standing start, I don't think I've done anything to really improve it. I printed off copies of the sheets with the original settings, then made notes on those regarding my changes. I'm sure I can find them. Other than those on the first page, not many changes.

When I first started making changes here and there, it was based more on hunches. Like "well that doesn't make sense, maybe this will work better" kind of thing.

A little more experience to base the "hunches" on now, and a lot more "seat time", under all sorts of conditions, won't hurt anything either.

An example: Matt (m@Robertson) had a note in one of his posts regarding the time the motor runs on after power is shut off, and using that to complete a shift. That makes total sense now. Is one of the things I'll be looking at is that, as I believe I set that to an absolute minimum, thinking that it might be a low speed control issue if left running longer than necessary. -Al