Bafang BBS01 ramp speed temporary stop

[Deere John]

Bad title, but whatever. I have one problem with BBS01 programming.

When biking on, say flat, and you have some speed. A sharp corner comes, you stop pedalling for two seconds to take the corner and then start pedalling again. Then the BBS stops assisting for a very short time. BUT... it then starts at lower assist power than when you came into the corner. And you loose speed. You have to wait for it to ramp up again so you get to the same speed you had before the corner.

How to tackle this?

I have some ideas, but the more I read the more confused I get so I thought I'd better ask first.

 

[peter.c]

Try and use the throttle to power out ,I found if you start to adjust settings it makes tight slow corners difficult the power jolts in sharply and creates its own problems

 

[Fordulike]

Programming the 'Start Current' to a higher percentage and changing the 'Slow-start Mode' to a higher number may sort your problem out.

Actually, I can't remember if a higher or lower number on the 'Slow-start Mode' makes it ramp up quicker, but have a play to see what suits you.

 

[tommie]

Look way down the Pedal Assist tab here for adjustments.......... https://electricbike-blog.com/2015/06/26/a-hackers-guide-to-programming-the-bbs02/

 

[Deere John]

Yes, I have read these but ok, I try with Keplers settings there,

Slow-start mode: was 4, now 6
Start current: was 20%, now 30%

And also, one other thing not related:

Designated assist level (PAS): was BDC, now 9

/edit: attached settings sheet

...

Bad idea to try all at once, but now I'll do that and have it like this for a while and see how it feels.

One thing I am worried about is that when stand still and startup it will ramp up too soon in that situation. It should behave like this that it sense no RPM from wheel sensor and then ramps up slowly, or, way better, a parameter for just that, "Ramp up speed when standstill" sort of.

 

[Deere John]

Ok, first try. It is better now! But still not perfect. Guess I will settle for this now anyway. Don't want to affect battery time. I don't like the fact that it ramps up quicker from standstill also now, burning Amps for no good reason. Wish it would be possible to adjust that but it doesn't look like you can do it unless you lower assist everytime you stop. Anyway, it works good enough now.

I also noticed I changed the "Designated Assist Level" on PAS instead of Throttle, if I follow that guide. Now I don't have any assist levels, always full need to change it back and set it to 9 on PAS-tab instead, makes more sense on the throttle.

 

[Deere John]

Have now tried a little more for real. Trail riding some very great trails with lots of transporting also. Did I say it was a MTB? Basically it is better, but not perfect. Battery life is slightly decreased, but still very good. On my new display C963 there is a Watt-meter and I have kept my eyes a little on it now. It peaks about 450W and continuos power about 350W. Battery lasts 50% after a long ride, that is great. So I think I will let this be for now. Have attached final parameters here also.

Coming from a Bosch CX with eMTB mode I have high demands but it is good now (I also have a front hub drive commuter bike). Two things I noticed compared to the Bosch CX, there are these two behaviour changes when I now use BBS:

1) Start pedalling before you usually would after a short interuption (this threads topic).

Just because the motor ramps up and you don't want to start from zero. If you, for example ride a slight uphill. Stops pedalling just short enough so that the motor stops, then start pedalling again. You loose speed because the assist is low. Before on stock settings it felt kind of hitting a wall. But even now after tweaking your flow is disturbed and that is slightly frustrating so to handle this one thing is to start pedalling just a little earlier (if you can do that in that moment of course).

Related is gear changing. Sometimes you really don't want it to cut power totally when changing gear, so you change gear in full assist basically. To make drivetrain a little happier you could try pedal very soft so that your own power doesn't add to motor power.

2) Use slightly higher gear than you use to.

Because the motor spins out quick. When I pedal with normal cadence (which is quite "high" because I come from road biking before). The motor stops to assist just when cadence is in sweet spot. So I often use slightly higher gear than I would do if was unassisted. And the RPM range is a little narrow. So on each gear I spin out just before changing gear.
That is adjustable though, I have the keep current setting on 60% (was 20% stock and that was terrible!). Guess it could be tweaked some more.

Related is top speed also. I have 10-46 cassette with 35T chainring and assist reaches about 31 km/h before it ceases. That with 700C tyres, would be interesting to calculate motor spindle speed if you cope


Ok, long rant but interesting observations I've done. Finally some last words about the Bafang BBS. No system is perfect. Bosch CX is very good but have some issues also that made me sell the thing and get Bafang instead. This system though is very impressive. It is high quality, easy to install and adjust. Silent, you almost don't hear it if it's not silent around you. Works very great but stock settings can need some tweaks to make it shine. And here we comes in to systems sweet spot. Although it is good as it is and for people just wanna slam it on and use it. It is very good for us that likes to tweak, there are many things you can buy and there are lots of information on the internet because it's popularity. Also the battery is standard, so you have tons of battery options as well. Very happy with my new bike and it feels now that I will keep it for long.

 

[Deere John]

Have read a little about this "slow-start mode" setting, it seems that a lower value makes faster acceleration. I tought it was a higher value you wanted have also read that on many other forums/threads. But in the guides it says the opposite:

Penov Guide
Slow-start Mode (1-8) – This setting controls how quickly the start current is reached.
You can make your bicycle accelerate smoothly and make it respond quickly. A value
around 4 usually works well for normal cycling. If you are mountain-biker then setting to
a low value will make the acceleration faster which might be useful but you should be
careful not to fry your controller and motor.

Hackers (Hessleien) Guide
Slow-Start Mode(1-8): 3\4\5\6\4 -Controls how quickly the power ramps and how much it overshoots. If this variable is set too high the PAS start will be jerky, if set too low you risk blowing the controller as with Start Current above. If you are in too low of a gear to start and this variable is set too low it can blow the controller.

Can anyone confirm this?

 

[Deere John]

...I tested myself, the guides are misleading.
Higher number = Faster start
(but as Hackers guide say, low value is bad also)