How to eliminate pulsing/cogging on Bafang BBS

[liontail]

I've played around with a few different BBS0X's, and in general I've found that they're pretty smooth, quiet, quality units.

However, the pulsing/cogging in the lower PAS modes at low motor RPMs is driving me crazy! I find this problem is much worse on the BBS02 - I purchased mine (a 36V 500W) about 6 months ago from elifebike.

I made myself a programming cable and played with the settings. Ultimately, I couldn't do much better than the stock settings, which I'm posting here.

The problem is made much worse if I increase the "Limit Spd(%)" at a lower PAS level (I tried this since Kepler is such a strong proponent of it - not a good idea if you already have pulsing issues!). According to Paul (Cell_Man) at EM3EV, this is just how these units work:

http://endless-sphere.com/forums/viewtopic.php?f=28&t=58780&p=957938&hilit=bafang#p957938

But I've read elsewhere that others have programmed the pulsing out, but I have yet to find out how they've done it.

Maybe it has something to do with "Keep Current(%)"? Ken Taylor talks about that parameter here:

http://endless-sphere.com/forums/viewtopic.php?f=28&t=58780&p=958593&hilit=bafang+pulsing#p958593

My question: anyone been able to eliminate or significantly reducing "cogging" on these units in lower PAS modes? How did you do it?

Thanks!
Henry

 

[geofft]

Going for a world record for thread resurrection here.. :lol:

Did you ever find a fix for this? I've got one of the early BBS02's that has this pulsing issue (under PAS, throttle is ok), a slightly later version of the drive I also have doesn't have this problem.

The only programming option that seems to help with this is 'Slow start mode', I've found that reducing this to '1' reduces the pulsing significantly but doesn't cure it. It also, unsurprisingly, makes the power ramp up in PAS pretty slow.

My feeling is that the problem is buried deep in the early firmware version and can't be programmed out, so maybe I'll have to investigate the possibility of updating the firmware. Risky I guess, but this motor is pretty old now, so I won't lose too much sleep if I end up bricking it...