Announcement

Collapse
No announcement yet.

What does Speed Limit % do?

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

    What does Speed Limit % do?

    On the Basic tab, there are values for Speed Limit % at each Assist Level. The two main authorities on programming give different explanations of this value.

    Stefan Penoff says:

    The speed limit sets at what speed (% of the maximum speed set from your LCD) the motor will reduce its power and just keep that speed instead of accelerating more.

    https://drive.google.com/file/d/0B9j...5Wa0lZNmc/view


    In A Hacker’s Guide To Programming The BBS02 & BBSHD, Karl Gesslein says:

    Asst0 Limit Spd(%): 1/0/0/1/1 – At power level 0 causes the controller to lower current gently to maintain motor rpm when 44% of speed limit is hit. Speed limiting is done based on motor RPMs not road speed. The throttle might not work in PAS 0 unless this is set to at least 1, it is really nice to have a hand throttle setting without any PAS intervention.

    What gives? Why the different explanations? Are they referring to different things? Does anyone know which is correct for a current model BBSHD?

    thanks

    #2
    I use the speed % in PAS to control cadence. that is in a nutshell what you can do with it.

    Comment


      #3
      I have the same question when I was making my study ,I saw this difference in expkanations. Which one is the right, the rpm or the road speed. I use tbe em3ev settings yet did not touch anything on this tab.

      Comment


        #4
        There's no factory documentation so no matter what you read on the internets everything is all just best guesses and i suggest you take it all with a boulder of salt

        My guess is that whether PAS speed% is based on pedal speed or wheel speed may be dependent on other settings like the ever mysterious "work mode"...

        Comment


          #5
          just use karl's special sause and you will be happy with the result.. i used his files for both bbso2 and the HD and both times i'm completely satisfied...

          Comment


          • AZguy
            AZguy commented
            Editing a comment
            I disagree very much with this. I've tried Karls and others and for my bike and my style of riding didn't like them at all. I came up with my own over time that I really like and it works far better than those.... for me...

            YMMV

          • intramorph
            intramorph commented
            Editing a comment
            yeah not everyone will like what I like i'm just speaking for myself here. also I like aggressive riding so it's perfect for my application.
            Last edited by intramorph; 08-23-2018, 08:22 PM.

          • AZguy
            AZguy commented
            Editing a comment
            My riding is often very aggressive - I ride in the rocky, sandy, steep pretty much daily. My past includes decades racing motos so no stranger to aggressive.

            It took a long time to get mine dialed in (still tweaking at nearly 4000mi) but it was worth it and it's nothing like Karl's. Once dialed in it's not only a far superior feel and more pleasant but my driveline is less stressed (not tearing up small cogs on the cassette any more, chain lasting longer) and my mileage has gone way up.

            And to be honest when I started I didn't realize it was so far from optimal until I got it better and then realized it could be better.

          #6
          It will definitely limit cadence (motor RPM), regardless of road speed.

          I THINK it sometimes limits mph as well, because I hit PAS cadence limits in low gears, but stabilize at a road speed in higher gears, below the Max cadence - all on same PAS level. For example, my PAS 7 tops out at 20MPH, in the top few gears, but won't go that fast in lower gears, where it's cadence limited.

          Not sure about the MPH limit, though! This might just be power limiting. I don't think so, because wind and hills (mild) don't reduce that speed. But I haven't really tested to prove it to myself.
          Last edited by JPLabs; 08-24-2018, 09:20 AM.
          Fabrication is fun! Build something today. Show someone. Let them help. Inspire and share. Spread the desire.

          Comment


          • AZguy
            AZguy commented
            Editing a comment
            During my long trek of fiddling parameters I noticed for a while it seemed to be limiting by road speed, but at some point it seems like it changed to pedal cadence and I'm pretty darn comfortable it's pedal cadence at this point. Pedal cadence is what i want to limit since my prosthetic leg can only go so fast before it won't stay on the pedal so I set the speed limit in all PAS levels to something like 72% since that's as fast as i can go - it used to be lower but as I got "better" i was able to raise it and whether in first or top gear it is limiting and it sure seems the same pedal cadence (I wish I had an easy way to measure pedal cadence).

            I don't really know when it seemed to change and I've fiddled about every parameter in there and my best hunch is that the "work mode" setting may have something to do with it - I sure wish I understood what that was supposed to do and how to calculate what it should be. I fiddled about with a lot of different values in there a year or so ago...

          #7
          Originally posted by intramorph View Post
          just use karl's special sause and you will be happy with the result.. i used his files for both bbso2 and the HD and both times i'm completely satisfied...
          i have been using Karls and have been changing stuff on my Ultra... I used his settings on the torque values for both his Ludicrous only and Ultra max only and found that the ludicrous is better even though I don't have a ludicrous controller... I would be interested to see what AZ Guy has for his settings, I too ride a lot of steep hills and old logging roads here in Vermont and am finding battery life with the Ultra to be problem even though I have 17amps... My bbs02 gets better mileage with the stock settings and a 12amp

          Comment


          • AZguy
            AZguy commented
            Editing a comment
            I'm pretty sure this is my PAS current %'s and all my speed limits are set to 72% (I think) to limit pe3dal cadence as mentioned in the previous post...

            1 6% 1.8A 90W
            2 9% 2.7A 135W
            3 12% 3.6A 180W
            4 17% 5.1A 255W
            5 24% 7.2A 360W
            6 35% 10.5A 525W
            7 49% 14.7A 735W
            8 70% 21.0A 1050W
            9 100% 30.0A 1500W

          #8
          Originally posted by vtdownhiller View Post

          i have been using Karls and have been changing stuff on my Ultra... I used his settings on the torque values for both his Ludicrous only and Ultra max only and found that the ludicrous is better even though I don't have a ludicrous controller... I would be interested to see what AZ Guy has for his settings, I too ride a lot of steep hills and old logging roads here in Vermont and am finding battery life with the Ultra to be problem even though I have 17amps... My bbs02 gets better mileage with the stock settings and a 12amp
          Follow AZ Guys PAS settings. They are a very good starting point.Then individualize them for yourself. Think of PAS speed as cadence and experiment with those as well. If you are a young guy. Try speed settings at 85%. Move up or down from there.

          Comment


            #9
            I am going out for a ride today so I will try the different settings. I am 53 ride a lot of hills here so dialing it in is not easy... My bbs02 on my hardtail was great out of the box my new bike has the Ultra max with torque sensing and I am struggling with power to battery drain. Right now I have my PAS set to
            15
            25
            35
            45
            55
            65
            75
            85
            100
            All at 100% so I will dial it down to 85% and give it a shot

            Comment


            • AZguy
              AZguy commented
              Editing a comment
              You've got a linear progression which I had at first and didn't care much for. Once I had the [what should have been obvious] epiphany to make it non-linear I was much happier and settled in on a very simple exponential progression with every two steps roughly doubling power - every step is roughly ~1.4x (√2) the previous step.

              I made an excel calculator that's on another thread that takes min power, max power, min level and max level and computes all the other PAS levels based on the exponential progression if you're interested.

              I tried other non-linear progressions (parabolic, etc.) and settled in on the exponential which was my first crack at non-linear.


              Lately I've been riding more with the 3-level full-time throttle controlled (no longer pays attention to whether you are pedaling or not and doesn't do assist by PAS level) which is posted somewhere in the knowledge base - it's more work but sure is fun and much better when off-road. I still prefer the PAS operation on level ground and looking forward to when I finally get around to integrating the electronics to provide for both instead of having to switch the parameters..
          Working...
          X