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My experiences programming the BBSHD. It's a story.

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    My experiences programming the BBSHD. It's a story.

    Programming the BBSHD. I love it. It is nice that they allow users to modify the settings of the flash memory on the controller. They even give you enough rope to hang yourself.


    Before I begin this story you have to understand where I am coming from. I have put over 500 miles on this guy, with a direct drive rear 1000W hub:

    Click image for larger version  Name:	 Views:	1 Size:	1.24 MB ID:	54008

    The Pedal Assist System never worked right (the hall sensor was not sensitive enough to pick up the magnets on the crankset) so I used throttle only. It gave me an essentially infinite number of assist levels. I would twist the throttle just enough to give me the assist I wanted at the time I wanted it. It also gave me a nicely cramped hand after about 10 miles.

    When I first tried out the BBSHD I of course tried to do the same thing. It was a habit after all. When I first twisted the throttle I saw 1500W on the display and then my eyes widened as I realized they were not kidding when they said if you start on a hill, low gear, and juice the throttle you’ll fry the controller. My eyes might have been a bit wide too because the front wheel was no longer on the ground. Thankfully I let go of the throttle in time, which certainly had nothing to do with me about to fall over backwards on the bike from a super wheelie. No damage done to the controller as far as I could tell. I needed to adjust the twist throttle settings a bit. I had to change them to 1.1v to 4.2v, and cut the starting current in half to 5% (down from 10%).

    With that adjustment the throttle worked just as I had remembered from my old direct drive, except that when I started pedaling in the middle of it the throttle would be overridden by the pedal assist system initially, resulting in a super drop in watts to the pedal assist level (1% or 27 Watts in this case, down from about 300-400 Watts under throttle control). As I continued to twist the throttle it would eventually hit that magical BAFANG programmed mark where throttle became the priority. It would then ‘boost’ the pedal assist system by jumping to 1500W again. This really stunk, because it smelled of a bright stinking BAFANG firmware programming issue.

    I can appreciate the challenge, because you not only have to decide which takes priority, throttle or PAS, but also when. A human can do that easily, but a simple controller not so much. Ideally they would have a setting that was throttle only and disabled the PAS input entirely. It would be child’s play to go into the controller and disconnect the PAS, but then I would not have PAS and my cramped hand would come back. I am tempted to do it anyway and install just a switch or button that I could actuate to make it happen on demand. I am not sure what effect that would have on the controller, but it might be fun to try (possibly a good excuse for a new controller too).

    I would hope it would be easy in the firmware to disable or ignore the PAS input, but in practice I am sure that it is more difficult than I think to do, especially if they are using a cheap chip with limited memory and processing power. It might not even be physically possible, especially if the throttle voltage and PAS voltage meet up somewhere on the chip.

    It would appear my BAFANG programming friends in China decided to give PAS the priority and make the throttle mostly a ‘boost’ feature. The way it works now is that you start with PAS and if you need a little extra boost you can twist the throttle.

    Never one to give up, I figured that I could find that sweet spot in the settings where the throttle would take over right at the same level the PAS was operating at, thus allowing a simulated version of the way I used to ride. Alas, when I finally found that sweet spot, it would switch from PAS to throttle and back again over and over as they fought each other at the ‘sweet spot’. That wreaks havoc on the controller and is a sure way to fry it quickly. It works on light bulbs too, just switch em on and off enough and they’ll burn out quite soon. Well before their rated time.

    I bought the BBSHD for the express purpose of having a nice PAS system to commute to and from work. It performs flawlessly in this regard being able to pedal and then boost a bit when needed. I have to admit that if I was the BAFANG Company I would have chosen the same path because most of my customer base rides on nice ground. There is simply no better PAS system out there yet that I know of that lets you program the current and motor speed you want for up to 9 levels. I was able to program that throttle down from 1500W to 750W (hopefully saving the controller in the future) and still have nine levels of pedal assist. Overall I am very satisfied.

    The only thing this doesn’t work well for me on is single track trail riding, where that infinite number of assist levels (aka twist throttle) and the ability to rotate the pedals (without turning on the PAS) as needed to avoid obstacles is an absolute necessity. Thankfully if I decided to use it on single tracks I can just disconnect the PAS for a bit (I hope anyway).
    Last edited by MrScience101; 12-25-2017, 12:00 PM.

    On singletrack use PAS 0 and throttle only. Pedal as you want with no PAS interference. Use throttle like variable PAS as needed


      It sounds like you may have one of the BBSxx's with the PAS override flaw - long thread here:


        Originally posted by AZguy View Post
        It sounds like you may have one of the BBSxx's with the PAS override flaw - long thread here:
        Read that thread yesterday. Interesting thread. I thought there was something different with my controller. When you get PAS dialed in how you want it is not as big an issue, but I miss being able to throttle with PAS still with my old one. So at its heart my Ludicrous controller is a bafang based controller still. It works well, so it won't be going back I don't think. i have a new BBSO2 controller, bought a year ago from em3ev, because luna was OOS at the time. Still have not installed it. I hope it is old 3077 stock.
        Last edited by New Mariner; 01-16-2018, 07:39 AM.


        • AZguy
          AZguy commented
          Editing a comment
          My understanding of the ludicrous controller is they are the same as the BBSHD controller except the MOSFET's are better and they decreased the currents sense resistance in half to "fool" the controller to handling twice the current...

        It's funny - when I first got the BBSHD I noticed the behavior right away, shrugged my shoulders, and told myself I guess that's just how they are - oh well. I have a bafang hub that works as expected so I understood the proper behavior (jeez that sounds like ma telling them how to have dinner at the table).

        I've got my PAS dialed in super well (although like most of us constantly tinker with it) and so the lack of it doesn't bother me so much as it might.

        The problem [for me] is that now that I understand it doesn't have to be that way I'm missing it more and more - go figure...


          I miss it every time i hit the throttle while in PAS, because PAS cuts out. Itis a funny feeling, that I don't like, but I am stuck with. Otherwise it works perfect, is easily programmed, and occasional burst of 60 amps make me forget about it


            The only time I generally use the throttle while pedaling is for brief bursts when I need it so instead of being able to get anything the throttle can do we're limited to it just putting out the max. I don't really like hammering the driveline with full power when I need that burst so I set the throttle to only 67% maxx current (~20A) so it limits it to ~1000W.

            The principal other times I use throttle is when it's too rough for me to pedal - I got one leg so if it gets rough my plastic foot will often leave the pedal unless I stop pedaling - so I'll go throttle only through the rough stuff which works fine so no big deal here.

            Because of the missing leg I also use the throttle just to get that initial push which again works fine.

            Still, now that I think "oh wouldn't it be nice if I could just add a little throttle instead of 1000W" I'm missing it more....