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BBS02 on 2008 Kona Hoss and initial mountain bike program settings

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  • BBS02 on 2008 Kona Hoss and initial mountain bike program settings

    The build was super easy, many thanks to Rod at Luna-Mate in Perth Australia.

    After looking at the commercial offerings for electric Mountain Bikes in Australia (the cheapest was $3500, not in stock), I decided to look into converting my Kona with the Bafang for less than $1000 usd with battery, and though it does not offer the same kind of torque based pedal assist as what I was hoping for (i.e. Bosch, Yamaha), I am so far pretty happy with its power handling.

    Here's the bike (photo 1).

    I was a bit stumped by the mounting of the battery pack, as the holes in the plastic did not match up with my water bottle bolts if I wanted the battery to fit. An online video recommended drilling the metal plate, which worked well (photos 2, 3).

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    All I really needed for the build was the bottom bracket and crank arm removal tools, allen wrenches, twist-ties, a twist-tie snipper, the Luna-Mate tool, and the drill press to drill out the metal battery plate. It only took a hour or two to put it all together (see parts photos).
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    My brakes are Shimano hydraulic Strokers and there is nothing on the brakes that actually creates a gap when the brakes are applied, so I wasn't able to figure out any way to use the hydraulic brake sensors, but I am finding I don't really need them, as when I stop pedalling, the motor stops, and I am getting used to a new system of shifting (stop pedalling, move shift lever, pedal). So the only attachments to my Bafang are the display and thumb lever to set the PAS level, and the speed sensor on the back wheel (no throttle).

    For the Luna Display, I needed to change the PAS levels to 9 (default was 5 levels).

    I wasn't too happy with the default programmed configuration--it seemed like not enough power for the initial pedalling, then after a delay, the power came on way too strong and fast. It really seemed like the default settings would plow you into trees on a typical mountain bike ride.

    After a few trial runs using the programming cable supplied by Luna-mate, I am using the following configuration--this hasn't yet been tested a lot, but seems pretty good for my initial runs. What I was after was a pure pedal assist system that gave a little assist, but right away, even at level 1.

    Here are my initial settings which seem to provide a good PAS mountain bike feel:

    0 1 1
    1 15 100
    2 25 100
    3 35 100
    4 45 100
    5 55 100
    6 65 100
    7 75 100
    8 85 100
    9 100 100

    Note that the first three Current levels are well below the default. For the Speed Limit, my logic for the 100% settings, is why limit the power based on speed?. Even if I am going fast, if I click the PAS down, I still want that extra bit of assist. It felt weird shifting down the PAS and then having the power cut out completely because the speed limit settings changed with the lower PAS. Setting all Speed Limits to 100 seemed to make for smooth power transitions using the PAS thumb control.

    When I am mountain biking I really just use PAS levels 1, 2, and 3 mostly, because I like pedalling, but I wanted just the extra bit of power. but not too much, hence the 15/25/35 for the first three levels. This made the bike feel like more the Bosch mid-drives I had tried, but with the requirement of switching the PAS with the thumb control more frequently. These are the Pedal Assist settings I am currently using:

    PEDAL ASSIT ----(EDIT--these initial values were all wrong, see post below for updated settings--the LimitlessBBS02)
    Start Current: 20% (maximum). (Now 3%)
    Slow Start Mode: 8 (now 3)
    Start Degree: 4 (now 5)
    Work Mode: Indeterminate (changing this makes the unit react oddly)
    Stop Delay: 10 (now 6)
    Current Decay: 8 (now 6)
    Stop Decay: 0. (Now 6)
    Keep Current:: 100% (now 65%)
    Attached Files
    Bafang BBS02 on 2008 Kona Hoss drilling out the battery mount from Luna-Mate for installation on bike. the battery mount on the tube.
    Last edited by deuce4; 1 week ago.

  • #2
    Nice build. And thanks for posting your thoughts and settings for the feel you wanted from your BBS02. Now that I have my eCruiser going, I can start experimenting with my Soma B-Side BBS02B's programming for off-road use. What did you find to be the best source for understanding the Bafang programing? Is it easy to save the standard settings before making changes, so they can be reloaded if you want to return to stock? Finally, is there a detailed list somewhere with the name of each setting and what it actually does, with the range of entries and how small or larger numbers affect the setting?


    • #3
      I am gathering some great info, and will post soon. This link is the only one I have found to the latest config tool:
      (by the way, we are not really "programming" the Bafang drives, we are simply changing the configuration settings, hence we should refer to the cable as the "configuration tool" rather than programming tool).

      The above link comes with all the configuration profiles (.el files) mentioned here, and more. It also comes with Karl's manual.
      Last edited by deuce4; 2 weeks ago.


      • #4
        Ok, have been gathering information, and it appears there is a lot of different and often contradictory theories about the best configurations of the Bafang drive.
        Some mountain bikers have opted to eliminate the PAS system entirely, and rely solely on the throttle. As I don't have a throttle, my goal is to see if the Bafang can really provide a mountain bike with pedal assist as reasonably close as possible to the more expensive torque mid-motor drives (Bosch, etc.).

        First off, it seems that all the settings with a PAS 1 of 40% or more current are made for road bikes, not mountain bikes. For mountain biking, a low current for Pas 1, gradually increasing is best. The two configurations out there that do this are the Limitless (recommended by Joel at Luna-mate) and Kepler. Here are their settings for the BASIC tab:
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        They are similar in principle, yet I do not understand Kepler's logic for setting PAS 0 current to 100? I have tried the Limitless, and they work well when you are using the thumb level to increase/decrease the PAS level dynamically when riding depending on how much assist you are looking for.

        For the Pedal Assist, things are not as straightforward (limitless on left, Kepler on right)
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        There seem to be very different theories about start up current and start-stop mode, as you can see in the different values for Limitless and Kepler. The literature doesn't even seem to agree on what the settings actually do--some references suggest that Start-Stop at 8 would be the fastest startup (see Kiiku's manual ), and some suggest that a setting of 1 would be the fastest (see Joel's comments below).

        For the brake cutoff, Another theory (passspecial sauce?) who suggests that when mountain biking without a brake sensor, you want the power to cut off as soon as possible:
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        As recommended by Joel below, I plan to use the Limitless settings, though I do want to find out more about the startup current and slow start mode through some trials.

        Here are Joel's insightful notes sent via email:

        AUG 31, 2017 | 07:07PM UTC
        Joel replied:

        Hello John,
        I’ve gone through Kepler and Karl’s settings, as well as many others, to learn how to change the settings and get the best use of the motor. All of the other profiles are wrong because they didn’t continue to change and improve them as they learned more. The settings in the “Limitless” series for the “Pedal Assist”, and “Throttle” tabs is really as good as it gets.
        It’s really very simple. PAS doesn’t work on single-track since it is impossible to keep pedaling steady while dodging obstacles and cornering without catching a pedal and going down. So, PAS is for roads, paved or unpaved, and throttle is of single-track. While the bike is being ridden, the resistance is in a state of constant fluctuation, so any control on the motor has to capable of fluctuating as well, or it becomes an artificial inhibition instead. All of the PAS speed limits become artificial inhibitions, because they cannot fluctuate with the variable demands of the bikes resistance while it is being ridden. I have tuned PAS for the most transparent riding experience by removing all speed limits, and setting “Work Mode” to “Undeterminated”.
        The idea behind my PAS settings was to keep the current low, and the intervals tight, so I can use all 8 levels when I ride. The PAS levels on all the other profiles are always “not enough”, or “too much”. I wanted to reduce the intervals enough so that the next step up is “just enough”, or the next step down is “just enough”. The settings on the other tabs have already been setup to ramp up slowly and gently, yet cut off power as quickly as possible. The throttle as well has been set to ramp up from 1%, instead of 10 or 20% for a smoother start, to reduce shocks to the drive train. The goal is to leave the settings in the “Pedal Assist” and “Throttle” tabs alone, and work on the PAS settings till they are close enough together to be able to use all 8 levels on a road that includes hills.
        Sorry the link I included didn’t work for you. Downloads are only allowed on the forum if you are logged in, if not logged in, clicking on a download will give an error instead. What I ask of you is to sign up on our forum, download the file and run the program, then load the LimitlessBBS02 profile, and “Write Flash” to your controller. This will copy the whole profile at once to your controller. Please load this profile unaltered and try it out, using PAS on a road with a hill. Then send me an email, describing your feelings about how well it worked with your riding style, and how it felt. Then if there are any changes to be made, we can start working on them from there.

        Thank you,

        SEP 01, 2017 | 02:28PM UTC
        Joel replied:

        Hello John,
        PAS won’t stress the controller, heat stresses the controller. Sustained high throttle runs without enough cooling time between them will toast a controller. There’s an important reason for a slow start. It is to reduce the shock loading of the drive train. I’ll quotefrom the "Help’ file,
        Start Current [%] – The startup current when you start rotating the pedals. A value of 10% works
        well, if the maximum current in the Basic tab is set to 25A and Start Current is set to 10% you will get
        2.5A start current. This will lead to smooth start and will not load the internal gears too much. If you set
        this parameter to very high value you can damage the internal gears and the motor.
        Slow-start Mode (1-8) – Controls how quickly the start current is reached. A value around 4 usually
        works well for normal cycling. Setting to a low value will make the acceleration faster.
        Crank Trigger Pulses – Sets how many pulses from the pedal sensor are needed before the motor
        starts. Full pedal revolution on BBS kits is 24 pulses. Do not set below 4. The setting of 10 works well as
        it doesn’t start with just a small movement and require too much rotation.
        Setting your Crank Trigger Pulses below 4 is dangerous because the pedals have to be positioned from time to time to avoid catching them on obstacles. The small movement of the pedals for positioning will briefly trigger PAS assistance potentially catching the rider off guard and causing an accident. Setting the start current higher wears out the motor’s internal clutch/freewheel faster, so I don’t recommend setting it above 1%. Changing the Slow Start Mode is where I recommend making the biggest changes. A Slow Start Mode of 1 makes a surprising difference. The Slow Start Mode changes the slope of the startup ramp, making it the ideal tool to fix what you are trying to fix. That is, quickening the response time to pedaling, without making the pedals too touchy. I would recommend reducing the Start Current [%] to 1, the Slow-start Mode to 2, and Crank Trigger Pulses to no less than 4. Than if you still want faster response, try reducing the Slow-start Mode to 1.

        Thank you,
        Hope this helps as a start to others trying to figure all this out. Please let us know!

        John Middendorf
        Last edited by deuce4; 2 weeks ago.


        • #5
          Do you enter the wheel diameter setting and will it let you enter 10th's using the cable, or are you forced to select one of the preexisting diameters like when setting it on the display?

          I think I need a 29.5" diameter setting to get an accurate speed and distance reading...


          • #6
            UPDATE: I believe I found the ideal mountain bike settings. Essentially all the same as LimitlessBBS02 above, but with a few changes:
            --START CURRENT: I upped my start current from 1 to 3%, seems to give a little bit better pickup without causing too much stress on the system.
            --PAS level 9 (Basic panel): I decreased the current limit to 90%, too high and you feel like clown pedalling when flat out on roads (note: 36t front chainring).
            --KEEP CURRENT SETTING: This is the most important setting for mountain biking, in my opinion. I changed this to 65% (from the Limitless 100%) feel I get the best cadence for each PAS level. At 100% it was too quick and I couldn't keep up with the cadence (note: 36T front chainring). 65% seems perfect, still requiring real pedalling at all levels. (good explanation of the Keep Current setting here: )

            I really found these settings to be ideal for mixed road/offroad riding, which most of my mountain bike rides entail. By ideal, I mean that I still feel like I am pedalling and controlling the bike through my shifting and cadence, but just with a lot of help from the Bafang unit (i.e. never clown pedalling).

            On lightly hilly roads, I could bump it up to PAS 9, using about 600W (uphill) and going up to 40kmh. Then on the trails I only needed PAS 1-3 to make me feel like I was 25 again on the up and down singletrack (using up to about 200W--which seems about right--back in my youth, I could probably put out 350W, now likely only 150-200W on my own power--I'm older now!).

            I should also note that I had to switch out my controller on my stock 750W BBSO2 Version B unit--I blew the first controller (not from bad settings, but during a configuration session, I broke the green plastic protector on the display line and the exposed pins shorted on my metal workshop table, apparently blowing a MOSFET). The replacement controller I got from Luna-Mate was a 1000W controller (perhaps one for the BBSHD?). The 1000W controller seems to provide more power for a given PAS, even with the max current set at 18A.

            Rider, regarding the wheel diameter, I am not sure if it matters much in terms of performance, just the reading of speed (though some people seem to hack this to get a higher top speed).
            Last edited by deuce4; 1 week ago.


            • #7
              Also, here's my handlebar configuration with the PAS controller and the cutoff button on the left side (shifters on right side).

              Note no throttle-some people seem to think a throttle is good for mountain biking--I really can't see it. Shifting the PAS level seems much more versatile.

              The button cutoff is great for shifting, and is much better than having to stop pedalling to shift gears. I can't really see any advantages to the brake cutoff (they didn't work with my brakes anyway) when you can just mount a button to temporarily stop the motor during shifting (usually when I am braking I am not pedalling!).
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              In lieu of a torque sensor, I think these settings feel very close to what you would get with a more expensive mid-drive unit (i.e. Bosch), I believe, while actaully getting a lot more max power. I think it would be good for Bafang to incorporate a temperature sensor for the unit. On my last 20Km ride, my unit got warm, not hot, but knowing the exact temperature would be good to keep your unit healthy for longer runs. cheers.
              Last edited by deuce4; 1 week ago.


              • #8
                Originally posted by deuce4 View Post
                ... The 1000W controller seems to provide more power for a given PAS, even with the max current set at 18A. ...
                I know changing the assist speed limit cutoff will change how much power is applied at each power assist level. Also, the controllers seem to be set differently from the factory on each motor; at least the two I have bought had different settings when received.

                Originally posted by deuce4 View Post
                ... Rider, regarding the wheel diameter, I am not sure if it matters much in terms of performance, just the reading of speed (though some people seem to hack this to get a higher top speed).
                I agree. I was looking to get the most accurate reading possible and there isn't a 29.1 setting. With it set to 29 my mileage appears to about 0.10 of a mile off. IMHO it'd be nice to have tenths in the display setting.


                • #9
                  Rider, agree, the two controllers I got had quite different settings. I can't imagine anyone just depending on the variable factory settings, which are all crap for trail riding. Hence, the configuration (programming) cable is an essential piece of equipment. Wish there was another way to plug it in rather than having to disconnect my display every time, especially since I have three unused connectors in my system.