BBSHD programming

[Eric Luna]

Wow great informative post....

We at Luna spend some time once a month or so thinking about and tweeking our program settings trying to find the optimum setting for most of our riders....but realize best would be a special program for different kinds of riders.

For example Pedicab riders need their own special programming ..

BY the way, I respect Keplar a lot and always default to his settings on settings we are unsure about.

One big question i have because i am learning about programming myself....is that as far as we know there is not a way to limit throttle with the program settings...that they are for just PAS only.....i have a hard time accepting this to be true since many american riders are gong to be throttle only.

Has anyone figured out how to dial down the throttle in different settings?

[JPLabs]

Skymon,

The PAS sensor makes multiple signals per crank rotation. think of this variable as how long the motor will stay on after the last pedal pulse. The shorter the time, the faster you need to pe pedalling to make another pulse before it turns off.

[skymon]

Thanks. That helps. I get it now.

[Lostboy423]

I definitely noticed that the motor doesn't kick in at low cadence since I lowered the time of stop

[JPLabs]

I changed time of stop from 5 to 10 and it starts at lower cadence. Confirmed.

My new settings have a great speed spread, bit there is now noticeable surging in higher gears. Also the RPM sags too much on hills. Need to work on it more.

Edit: For limiting the throttle, see M 2.0 suggestion, below.

[New Mariner]

Thanks for doing all this work and sharing.

[M 2.0]

Eric / JPLabs,

From my experimentation you can limit the throttle power to the assist level set in the basic tab with the “Designated Assist Level” in the throttle handle tab.

JPLabs ; Would not setting the "End Voltage" to 2.2 x100mV not limit the power but make the actual throttle ramp up in a shorter time; meaning a shorter response.

[JPLabs]

Eric / JPLabs,

From my experimentation you can limit the throttle power to the assist level set in the basic tab with the “Designated Assist Level” in the throttle handle tab.

JPLabs ; Would not setting the "End Voltage" to 2.2 x100mV not limit the power but make the actual throttle ramp up in a shorter time; meaning a shorter response.

Oops, I guess it does. I was thinking throttle output limiting, not throttle input limiting. I'll remove that suggestion. Thanks for the correction!

[JPLabs]

Update: After playing with the settings more last night, I'm still getting surging with PAS in higher gears, with my new PAS Speed and Current limits as described above.

What I mean by that is the PAS control comes up to speed, then slows down again, and repeats. If I'm in PAS 4 and 7th gear, for example, the bike speed varies by maybe 3 mph, cycling up and down, over perhaps a 10 second period. Really annoying. The bike did this a tiny bit with the stock programming, but it's worse now. It surges on the flats at 15-18 mph, where the motor has plenty of power for the load, so I think it's an issue of control stability, not simply running out of power.

My new setting changed the spacing of the PAS levels, but that shouldn't affect the way the motor behaves for a given speed % setting, unless there are more variables not exposed to us with the tuning software. The fundamental thing I changed relative to motor controller behavior was raising the current limit for a given PAS speed %. I expected this to cause the motor to hold speed better, not worse.

I suspect that the Keep Current and Current Decay need to be re-tuned now; they influence the dynamic response of the power control.

I thought that because I raised my PAS current vs speed ratio, perhaps my Keep Current was now too high, and I was overshooting. It was at 60%. I tried 40%, 25%, and then 80%. None of these eliminated the surge. 25% did seem a little better. But so did 80%. Not sure, it was hard to be consistent with each test ride.

I can always try setting the Current vs Speed ratio back to where it was stock. But the bike would lose speed more than I liked on uphills with that setup, and I am trying to make that a little better with the higher Current limits. So I'd rather be able to tune it to work like this if I can.

Does anybody have experience with this type of surging behavior? Were you able to eliminate it? Any suggestion for what variable I should try tuning next?

--

The motor doesn't regain cadence as well when I upshift now, in higher gears, either. If I use throttle it will hold speed fine.

I changed from the 30T to 42T chainring shortly before changing these settings. This symptom may be entirely due to that hardware change. When I upshift now, it's a bigger gearing step with the 42T than it used to be with the 30T, so a bigger load change for the motor - the motor speed drops further so it needs more current to maintain power. That bigger step seems hard for it to recover from. Maybe I need to further increase the PAS Current limits so it has more power in reserve for upshifts. Or maybe I'm just trying to pedal too slow for it to work well, but since throttle can do it, I want PAS to be able to do the same. That line of thinking tells me I should just increase the PAS current limits more.

Motor does not get very warm with testing, but my test runs have been only 1-2 miles for each program change. I'm trying not to hurt it. I know I risk that, and I'm OK with fixing it if I do, but still.....

Please share your thoughts or suggestions.

[M 2.0]

JPLabs, Yes changing from 30T to the 42T (Which I prefer) does effect the cadence programming. As Eric stated each different hardware setup would need it's own setup for optimal programming. Now have you set the "Motor Mode" to 10, I found it made allot of other settings more stable thru range. I have also set my "Current Decay" to 6" and remember if you set your Basic "Speed Limit" settings at any thing under 100% your power will drop off from what the controller Speed Meter is reading for speed. I would leave the Throttle Handle Mode at "Current" as this will be the most stable for the controller.

I am still experimenting as well and will release my setup once it is where I like it.

My hardware is 42T front with a 11-34T 9 Speed rear.

There are just my thoughts and opinions.

[JPLabs]

Thanks M2.0! I'll try those suggestions today.

What are your current limits, in relation to your speed %?

You are the first guy I've seen with a recommendation to change the mode setting from unspecified. You mean 'Work Mode' on the PAS screen, right?

"Work Mode (Angular speed of pedal/wheel)*10". In the software, the available settings range from 10 to 80.

According to the above definition (from the software), my work mode value ranges from 10 in first gear (1:1 ratio) to 2.6 in high gear (11/42). The wheel angular speed it HIGHER than the pedal speed, so the result will always be less than 10 unless you have a mega granny setup. So, I suspect the definition is inverted and it should really be speed of Wheel/pedal*10.

That would give me values from 10 in low gear to 38 in high gear. Which fits the available settings better.

[Eric Luna]

i am not the programming expert (a respected guy in our crew is who actually has time to go out and ride and test the bbshd) and wish i could contribute more to the conversation....but one thing i understand is that speed % is the speed of the motor...and we decided that should always be set to 100 percent on all levels of assist (same as keplers settings) and limit power in other ways in the lower levels....we have not heard a good reason (yet) for limiting that number.....

JPL, can that throttle limit be adjusted separately in every assist level?

[M 2.0]

For mine I set Current% from 1 as 11 then add 11 to each stage, yes stage 9 would be 99. For me I like a little space at the top. For current I start as stage 1 with 44 then add 7 to each stage with 9 set at 100%.

As for the "Work Mode" on the Pedal Assist Tab, You are correct about the calculations for it. The reason I prefer to set a number (10) is the the controller has a set state instead of try to have an unknown variable that it will randomly set. This give you more control on the overall program. I agree that the definition should have been Wheel/pedal*10.

I hope this is helpful.

[JPLabs]

Yep, sure was.

[M 2.0]

@Eric, I thought the Basic Speed setting is good if you want to use the Pedal Assist "Current Decay" setting by allowing for the current to drop off at set "Speed Limit%".

[JPLabs]

i am not the programming expert (a respected guy in our crew is who actually has time to go out and ride and test the bbshd) and wish i could contribute more to the conversation....but one thing i understand is that speed % is the speed of the motor...and we decided that should always be set to 100 percent on all levels of assist (same as keplers settings) and limit power in other ways in the lower levels....we have not heard a good reason (yet) for limiting that number.....

JPL, can that throttle limit be adjusted separately in every assist level?

Eric,

No, only the PAS current for that level. And the throttle overrides that limit. There is only one global throttle setting for the voltages. What M2.0 suggested sounds like it will let you set any current limit for the throttle, but all the time. Set the Designated Assist Level to 4, for example, and the max throttle current will be same as PAS4 limit. As I understand it...

This:

From my experimentation you can limit the throttle power to the assist level set in the basic tab with the “Designated Assist Level” in the throttle handle tab.

As for the 100% speed settings for all levels, doesn't that cause the pedals to spin super fast in 1st gear, even on PAS 1? Can you still cruise slow and easy, without spinning your feet into a blur?

----

I tried M2.0s suggestions. Set Current Decay to 6 and Work Mode to 10. It significantly reduced the surging! Great suggestion. It still slightly surged over a narrower range of speed and happened faster. Much improved. Next, I tried Mode set to 25, and that's at least as good. Will test more.

----

I, too, thought the PAS simply set motor RPM and only motor RPM. It seemed that way with my 30T chainring - I could set a cadence with PAS and hold it with any gear. But when riding in PAS with my 42T, I noticed that the RPM would not be maintained in higher gears. I'd shift up, and my cadence would drop, with no MPH gain. I thought this was perhaps because I was exceeding the available power for my settings.

So today I hung the bike from the rafters and ran a simple test. I'd set a PAS level, spin the pedals up with no load, and start up-shifting. What I observed is that the PAS would always run at the expected RPM for that PAS level in the first few gears, but above a certain gear/MPH, it would reduce cadence more and more with each successively higher gear. The higher the PAS setting, the higher the gear this happened in.

The controller appears to be changing from constant RPM control, to constant MPH control, above a certain ratio of wheel RPM to pedal RPM.

Sound familiar? That's in the definition of the Work Mode setting. Maybe this is the behavior determined by the Work Mode setting. We will need to test more and find out.

Now that I know this, I'm changing the PAS level more while shifting, matching both for the speed, and it works great. I just need to change the PAS level a lot more often than I used to with the 30T. I don't like having to do this and would prefer it if was purely a cadence setting, with no speed override.

With my Mighty Mini and old settings I never ran into the speed limit. It may have only started doing this after I changed the Work Mode from Undefined to a set value. I think it did it before that with the 42T, but I'm not sure. Maybe that was power limiting.

This is interesting enough to investigate further. Does the Mode setting determine the cadence at which the speed limiting starts? Or maybe it's using the Speed % settings in the PAS tab to do this? Or a combination....?

More things to figure out.

[M 2.0]

JPLabs, Have you tried to increase the "Work load" setting and nothing else to quell the surging?

What is your "Keep Current%" setting?