Bafang BBS02 Throttle/PAS Simple Fix

Rassy

1 MW
Joined
Apr 8, 2007
Messages
2,099
Location
Eugene, Oregon USA
As most BBS02 and BBSHD enthusiasts know, Bafang introduced a change in 2017 that changed dominance from the throttle to PAS which resulted in poor throttle response when you were also pedaling, even in PAS level 0. I took part in an experiment with guidance from Fechter to make an electronic change within the controller cavity which returned dominance to the throttle and made the 2017 and newer controllers perform the same as the earlier controllers. This is well documented here:

https://endless-sphere.com/forums/viewtopic.php?f=28&t=93977

After working great for three years my DIY fix started failing and I removed the fix to verify that the controller still worked as it had originally. It did work as original, but instead of redoing the fix I decided to try something different that did not involve any delicate electronic installations. So right, wrong, or indifferent here is what I did:

First I cut the small grey PAS wire in half. This wire is in the controller cavity and is one of the four wires attached to the small connector. Do not confuse it with the grey wire attached to the five wire small connector which also includes a blue wire.

Then a new wire was connected to each loose end of the grey wire where it was cut and these two new wires were run out of the controller cavity. I used a small two wire conduit and cut a small piece of rubber from the top of the area where other wires pass into the controller. This controller already had some potting removed from that area, so with a new controller you may have to remove a small amount of potting. I have not sealed around the new wire yet, but will do that later.

Then for my initial testing I ran the two wire conduit to a toggle switch mounted on the handlebar. Everything worked as expected, namely when the switch was closed the BBS02 worked the same way as when it was delivered. And when the switch was open the PAS was turned off and the throttle worked properly in all PAS levels whether you also pedaled or not.

It was very easy to smoothly transfer from using PAS to using the throttle and vice versa, but it was a nuisance to have to flip the toggle to make the transfer. So I considered various options that would allow me to eliminate the toggle switch. I finally settled on a simple option of using a latching button switch handy to the opposite thumb from whichever side the throttle is on.

For me, this was a perfect solution, because I already had a latching button switch at that location. This switch was connected to the brake circuit so that I could easily cut off the PAS in situations such as when encountering heavy pedestrian traffic on a multi-use path, etc., and I used it often. Now, the same button serves the same purpose even though it doesn't kill the entire system it does kill the PAS, which was all that was really needed.
 
Hello.. thank you for posting another solution to this pain in the butt problem. Is there any way to access the gray wire from the outside of the controller and put the switch wire there? If I strip away some of the black insulation to the 8-pin wire can a gray wire be found there? I'd love to see some pics of your switch location.
 
Sorry not to see your question earlier, but no, the gray wire goes directly from the sensor located within the casing to the controller, so there is no other way to get to it besides within the controller cavity.

As far as the switch, I just used a basic motorcycle light switch that is made to go on a handlebar, but any on/off switch located anywhere you can reach it will do the job. I do like the rocker type switch because it is easy to push with my thumb and easy to tell which position it is in. I went on a 36 mile ride today with a friend and a couple of times when I went to throttle only mode while climbing a hill I forgot to switch back to PAS after cresting the hill, and later wondered (briefly) why I was working so hard once I was down of the level road again.

Oops, I see a little confusion there. I kept both the latching button on the trike a rode today, which cuts off everything, both throttle and PAS, because it is plugged into the brake cutoff connector, and I added the rocker switch for the PAS/Throttle fix.
 
Thanks Lassy. Am wrestling with same issue. One question though: What is a latching button ? Obviously some kind of switch but have never heard of such myself . Thanks in advance
 
A latching switch is just a push button that locks in the down position until it is pushed again and then releases back to the up position. So it works the same as a toggle switch or a rocker switch, except you always do the same thing to go from on to off to on to off, etc. but unlike a momentary button switch you don't have to hold it down, hence the word latching.
 
Thanks for that Lassy,
Simplist things used all the time oft escape the preoccupied mind!
On a somewhat related issue, my throttle is the thumb type . It appears far too jumpy. In attempt to switch it out for the so called half twist throttle which i trust will be smoother. Not so easy: The seller of the bike first told me I’d be voiding the warranty as it could not accept a half twist type throttle. Then he back pedaled a bit saying the concern was matching the given pin socket . I tried to go to Bafang usa for advice but was blocked at the front door because i had not purchased the motor from them.
Ok ….I look forward to getting through the corporate facade on this one in this forum .
Can you recommend or at least refer me to someone who sells any one or a few half twist throttles for my BBS02 ?
Thanks in advance ,
Richard
 
I haven't had a need for a new throttle for years, so can't help on where to purchase one. Any Bafang dealer that sells parts should be able to supply one. That is pure BS that a different throttle would void any warranty, but of course it has to be manufactured with the proper connector for the Bafang.

I just searched for "Bafang BBS02 half twist throttle" and all styles showed up in Amazon.

However, most dealers seem to set the BBS02 controllers up for the hot rodders that like fast starts. Personally, I prefer a slow steady start that doesn't stress the drive system. The throttle type will have little to do with this, and the only way to get what you want is to learn about programming the controller yourself. Lots of information in the forum on this subject.
 
Ok will go with amazon where i can see the correct pin connector. And or the programming issue am experienced with it a bit now seeking gentle starts but thats also part of the need for a natural operator controlled throttle rather than the dummed down pas system. :wink:
 
Flashing the firmware is quite easy and there’s a few threads here with links to firmware. K.I.S.S. :| :)
 
rstanley said:
Thanks for that Lassy,
Simplist things used all the time oft escape the preoccupied mind!
On a somewhat related issue, my throttle is the thumb type . It appears far too jumpy. In attempt to switch it out for the so called half twist throttle which i trust will be smoother. Not so easy: The seller of the bike first told me I’d be voiding the warranty as it could not accept a half twist type throttle. Then he back pedaled a bit saying the concern was matching the given pin socket . I tried to go to Bafang usa for advice but was blocked at the front door because i had not purchased the motor from them.
Ok ….I look forward to getting through the corporate facade on this one in this forum .
Can you recommend or at least refer me to someone who sells any one or a few half twist throttles for my BBS02 ?
Thanks in advance ,
Richard

A twist can be just as disappointing. Learn about programming parameters. There’s online programming tools now for MAC, Linux, and Windoze.

https://electricbikereview.com/forums/threads/bafang-bbsxx-series-apple-mac-access-to-programming.45249/
 
Rassy,
Im running on a mid drive BBSo2 on a DOST bike (Vancouver BC).
My existing of problem as mentioned earlier, is that the PAS is dominating the throttle instead of the other way around. As I red through the posts here it is apparent this was the manufacturer's choice which has left many unhappy, including myself.

I am going to try your fix, with potting switch (thanks for your earlier explanation). One other question on that: what size wire did you use to connect the cut wire in the controller to said potting switch on the handle ?

There is an added issue which may or may not be related : when pedaling on pedal assist mode only it has MORE power than when on Throttle only mode.
Whats causing that and what setting(s) would you suggest, if any to restore full power output in the throttle mode.



Thanks in advance,
Richard Stanley
Ashland Oregon
 
As far as wire size from the controller to the handlebar switch, I don't think it matters too much. 22 gauge is probably more than needed, but that was what I used.

As far as the controller settings are concerned, I like a gentle start and have been using the following for some time. I have purchased new kits with pretty strange settings, mostly resulting in harsh starts, but also some strange throttle limits, such as the one you described. Most of my settings were developed by trial and error to suit my riding style.

In the BASIC Section I set the Current Limit Amps to 15 which may be too low for some situations. Then for assist level 0 I enter a 1 for both current and speed. Then I enter 20(%) for assist level 1 and increase by 10 for each level, resulting in 100 for level 9.

In the PEDAL ASSIST Section I enter By Display Command for Designated Assist Level and Speed Limit, 10 for Start Current %, 4 for Slow Start Mode, 4 for Start Degree, Undetermined for Work Mode, 25 for Stop Delay, 8 for Current Decay, 0 for Stop Decay, and 60 for Keep Current%.

In the THROTTLE HANDLE Section I enter 11 for Start Voltage x10, 42 for End Voltage x10, Current for Mode, 9 for Designated Assist Level, By Display Command for Speed Limit, and 4 for Start Current %.

There will probably be some that disagree with my settings, which is fine with me. Hope this helps.
 
Thanks Rassy,
Am clear on wire size . (On reflection it was a relatively dumb question on my part, as one would obviously want to keep the gage the same as what they were patching into!

My start up current is set at 6 and the buildup of current and voltage i through the 9 PAS settings is relatively smooth.

What specifically bugs me is the drop in power when i go off my PAS - esp at level 9 mode ( it is set like yours to 100%) but when i stop peddsling and go to full throttle there is at least a 10-15% drop in output. .
What setting limits throttle output ? All i want is for the throttle to simply take over at same output as the PAS level.
Richard Stanley
 
That's a tough one to answer Stanley. At 82 I just ride for a little exercise and recreation. My speed limit is set at 20 mph, which is reached in various gears and PAS settings or by throttle. Most of my riding is done under 15 mph so that I can supply some pedal input.

I have read that some controllers limit the top throttle speed below that of the top PAS speed. I have no idea how it's done or if the BBS02 does this.
 
Rassy,
Im only 80 but I can sympathise with your cautionary driving attitude. Our problem here in Ashland Oregon is hills. Thats where , esp if you have to stop , you need the full power of the motor in the largest rear casette ( in my case the 34 tooth) through the throttle as starting by pedaling up hill is not fun for me at least !
So do I understand that making the change over to allow dedicated use of throttle does not affect the limit on the throttle ?
Richard
 
I get the hill issue. Before moving to Eugene, I had retired to Port Orford and had to deal with a 20% grade to get back to my house at the end of each ride. I'm not sure what various changes might affect. If you mean eliminating PAS by severing the PAS sense wire, or for testing, I think you can just unplug the PAS wires in the controller. I don't think that will change the throttle characteristics.

I have my max current set at 15 amps, and when I installed a BBS02 on a heavier friend's heavy trike I had to set the max current to 18 amps to get the desired performance. And that change applied to both PAS and Throttle use. I suspect you already have your max amps up to 25.

I think some have experimented with Speed mode instead of Current mode, but I don't know how that worked out or what differences it made. My experiments didn't give me the results I was looking for at the time.
 
Rassy, Joyce and I are in portland til sat am, driving back to Ashland. Any chance we can meet for say 15 min ?
Richard
541 488 1559
 
Pete,
Thanks much for the time spent with me during my recent visit. I will revert to the group as soon as learn something about what specifically limits the throttle output to below that of the PAS at the 9 setting..
Nice trikes by the way !
Richard
 
Hello Richard!

What an amazing surprise to see your name on this forum. A clue,,,,, you still have the Bat bike recumbent? :)

Wish I had read this thread as it was happening, I would have liked to have had the opportunity to catch up with you when you were in Portland last week. I live in this area now, since I moved up from Ashland in '92. And believe it or not, I still have the copy of the story done in the Ashland Daily Tidings where you and I did an interview about recumbents and designing them, promoting human power as transportation. I believe I also put in a quick jab about electric hybridizing them with human power, stating that electric assist cycling/commuting was inevitable.

And also hello Rassy. Been a long time since we communicated as well!

Thomas Breedlove
 
Hey rassy,

You've been a huge help to this community. I'm going to install the switch this weekend and my only problem I see is running the wire out of the controller. I believe you said you dug into the black rubber gasket. Any advice on this? Did you run the wire under the metal harness? Do you think you could just smoosh the wire against the rubber gasket if the wire was very thin? Thanks
 
I've done two of them. On one of them there was the shifter cut off, or whatever it's called, which I have found as worthless, so I just cut it off within the controller cavity and protected the wires so they wouldn't short, and used the hole in the gasket to run my new wires out. In the other I made a little channel in the rubber, just under the metal piece, and ran the wire through the channel so when the metal piece was replaced the wire was held tightly. In either case you can add liquid tape or whatever to seal the controller cavity up.
 
Tom, long time !! Please give me a call / text as i have managed to lose your message in attempt to clean mine up! It would be great to reconnect!

Pete, and anyone else on the bfang throttle befuddlement issue, I will get a programming cable and download the Mac adaptor ap or whatever I need to reset the parameters more to your suggested ones.
That aside am thinking about just replacing the rear large casette (34 t) with hopefully a 40 t casette to enable me to power up these hills without burning out the motor.
Technically its easy enough add three links to the chain and if necessary, change out the medium length derailleur for a long one.
My question to you and anybody else reading this is: Can a rear derailleur handle a 6 tooth increase?
Richard Stanley
 
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