BBS02 throttle is only on/off (not smooth/proportional)

[sulphuric99]

I just installed a new BBS02B 750W 48V (850C display) into a hardtail mountain bike with 27.5 tires and a 8 speed cassette. I used this kit from Amazon:
https://www.amazon.com/gp/product/B078YNVH9Q/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1

Overall, it works well. I've used hub motors for years, but I've moved to an area with very steep/long hills and mid drives make more sense. The default out of the box programming is wonky, but it's usable.

The pedal assist feature is terrible and almost useless to me, so I disabled it by programming the "Pedal Assist->Designated Assist Level" to 0. Level 0 is set to 0% current 0% speed. The throttle still works, but pas is completely disabled, which is what I want. (Setting level 0 to 1% current 1% speed, like a bunch of websites recommend, just results in assist level 0 going very slowly.) The default factory setting for level 0 was 10% current 10% speed. I would rather not take apart my controller to disable PAS.

The only remaining issue is the throttle, which is the one that came with the kit. It isn't proportional. It's either off or on. It's just binary, not analog. It was always this way, right out of the box with the default factory programming. I have to adjust the PAS level from 1-5 on the display, because the throttle is basically a button. All of my hub motor ebikes had very smooth proportional throttles, even using cheap controllers.

I have no idea how to fix this. I tried fiddling with the "Throttle Handle->End Voltage" setting with no change. Here's my configuration. Any suggestions would be appreciated.

 

[amberwolf]

It may be the firmware that's installed on the BBS02. There are various problems various versions of this system, because the firmware was changed to alter the way the throttle responds vs teh PAS.

Some of them there is no workaround for, and some of them you have to dig into the controller to alter things (because changing the settings doesn't do the same thing and affects other operations).

I suspect your problem is related to this one
https://endless-sphere.com/forums/viewtopic.php?f=28&t=93977
where the throttle only works when at full throttle if you are pedalling at all, though whether the hardware mod will fix your slightly different problem (where the throttle works this way whether pedalling or not), I don't know.

You might be able to simply disconnect the PAS sensor inside the controller to fix it, without building the fix-specific hardware and wiring it in.

Otherwise, the various things discussed in that thread are the only things I know of that fix BBS02b throttle usability.

Note that firwmare changes are also listed later in the thread...but you can brick your controller doing a firmware update, so don't do taht unless you're willing to buy a new controller and install it if that does happen.

 

[sulphuric99]

Thanks. I'll read that thread.

If this cannot be fixed, Bafang's BBS02 is flawed in a serious way (but not fatally). Makes me wonder: Hasn't anyone at Bafang ever used a good ebike with a proper proportional throttle? How could they even ship units with obviously broken firmware like this?

The hardware, mounting, display, cost, spare parts availability: all good. The BBS02 firmware is absolutely the weakest link. Here's hoping someone writes decent open source firmware for this motor.

 

[amberwolf]

There was a project started (by casainho, I think), but the hardware design made it not worth doing for some reason.

There are a bunch of threads about the BBSxx throttle problem, with various bits of info in each, if you don't find what you want in that linked thread.They're not all relevant in the linked list, but many are:
https://endless-sphere.com/forums/search.php?keywords=BBS*+throttle&terms=all&author=&sc=1&sf=titleonly&sr=topics&sk=t&sd=d&st=0&ch=300&t=0&submit=Search



FWIW, the BBS02 used to work normally, but when the B version came out, it was like you see it now, and that was years ago. Bafang has zero reason to care what their product users think or feel about their stuff, because they still sell it just fine. Once they get money, there's no reason for them to change things. (same for any other company)

When companies don't sell things anymore because of changes they made to them, they often just discontinue them, rather than changing them back.

The same is true of software, user interfaces in hardware and software especially; the companies simply don't care. (starting with the developers inside the company, who create things to meet their own desires, not that of their users; this is very very common even in individual developers).

 

[sulphuric99]

I took the BBS02 for another test ride, this time on a really long and flat road. Turns out, the throttle is *not* binary, but the range where the throttle is proportional is really small. It's possible I have a lemon for a throttle, so I've ordered a couple alternatives. (I'm really hoping it's just the throttle.)

Other than this issue, this thing is great. It goes up hills that would have just killed any of my old hub motor machines.

 

[amberwolf]

Turns out, the throttle is *not* binary, but the range where the throttle is proportional is really small. It's possible I have a lemon for a throttle, so I've ordered a couple alternatives. (I'm really hoping it's just the throttle.) ub

Try a 5kohm (or 10kohm, or somewhere between) potentiometer instead of a throttle. This is a better test, as it will give you a much larger adjustment range. You can test this offground, bike upside down, so you don't ahve to figure out how to mount the pot to ride with it. It should adjsut the motor speed over the full motor speed range, though it probably won't respond to the entire pot mechanical range because the pot has a higher range than the hall type does, so the bottom ~20% and top ~20% may not show any response...but the middle 50-60% should respond all the way from zero motor to full motor speed, gradually.

FWIW, I'm pretty sure what you're seeing is still the same problem others saw...but we'll hope it's just a bad or low-response-range throttle (those do happen, when magnets come loose inside or are installed wrong).