Bafang BBSHD controller questions.

[DuncanC]

When looking over the stock and various .el’s available a question arose. Why are there speed limitations on the 5 or 9 PAS levels. If I am using a derailleur to maintain my cadence at a specific PAS setting what purpose does limiting my speed serve? I’m using a FatTad with a Bafang BBSHD 1000 Watt which for my purposes gives me way more than sufficient PAS and throttle input. I probably over bought. Anyway to make things a bit more manageable I’m going to use a smaller chainring. What would be good settings to make the onset of PAS more gentle primarily at the lower PAS levels? As it is it is quite abrupt and jerky. Thanks in advance for any explanations or suggestions. It’s nice to have such experienced and knowledgeable ebikers to tap into.
Be safe, stay well and protect others,
Duncan

 

[Gionnirocket]

The Speed setting in PAS is % of motor speed, not ground speed.
So though all related and not absolute in its implementation it basically determines the cadence level at which the motor begins to stop assisting.
A good place to start to tame any BBS is to lower the Start Current on page 2
I've tamed my BBS02B way down... see here if interested.

 

[DuncanC]

Understood and thanks. Now another question. I read somewhere that the current% setting is actually an assist limit based on road speed. That doesn’t make any sense to me. My understanding is that it relates to the amount of assist (torque) the motor supplies which with an electric motor should be nearly independent of the rpm or cadence. I would think that setting a limit based on rpm doesn’t make a lot of sense. Maybe if it is used as a maximum cadence shutoff. In that case a single value across all levels would serve. Set that way the 9 levels of PAS would be simply selections of the assist you desire and could be easily increased or decreased based on need. That said I may be missing something. It is really too bad that Bafang has not made it clear exactly what every parameter does and how they are interrelated. I wonder if that information is actually available in Chinese and could be translated. I have a good friend (an MIT electrical engineer) who might be able to find that out.

 

[AHicks]

Duncan, you aren't the first to ask for a manual, so I can save you the trouble of looking. There isn't one. No way, no how, your wasting your time wishing or talking about one.

For an explanation of each line item, you're going to get some slightly different ideas of how they work from different people, based on their understanding of the function and experience in dealing with it.

I would HIGHLY recommend you bring yourself up to speed the best you can by studying some fairly well written articles as reference material-

I Void Warranties : Hacking The Bafang Ultra Max Mid-Drive Ebike Drive

There is half a dozen low power torque sensing mid drives on the market right now that advertise themselves as being between 250 and 750 Watts. The one thing that all these ‘low power’ …

electricbike-blog.com

Stock Ultra settings and Programming guide

By proceeding with the following you are acknowledging that you are following these instructions carefully and in full. Biktrix is not liable for any changes being made resulting in corruption of t...

support.biktrix.com

I am NOT saying I agree with everything in those articles. They will however give you a good leg up on the functions available. They're fairly well organized and good reference material.

One last thing I can share may be the most important. That's about priorities among riders. We're all going to be different. An example might be mine, where low speed control is really important to me. Others could care less here. They may be interested in commuting at much higher speeds. Then there are those that fall between, as well as those running at extremes. Point being, you need to get your head wrapped around those different use cases, and how the parameters affect them. It's only then you can begin to get an idea of how YOUR priorities might affect those parameters. That's when you hook the laptop up to your bike and make a change or 2 that you document well. Without your documentation, at some point you're going to realize you're totally lost, then you get to start over again.... -Al

Forgot to mention something. There a TON of info/reading material right here:

Bafang Forum

Discuss the brand, its products and upcoming models.

electricbikereview.com

 

[Gionnirocket]

Understood and thanks. Now another question. I read somewhere that the current% setting is actually an assist limit based on road speed. That doesn’t make any sense to me. My understanding is that it relates to the amount of assist (torque) the motor supplies which with an electric motor should be nearly independent of the rpm or cadence. I would think that setting a limit based on rpm doesn’t make a lot of sense. Maybe if it is used as a maximum cadence shutoff. In that case a single value across all levels would serve. Set that way the 9 levels of PAS would be simply selections of the assist you desire and could be easily increased or decreased based on need. That said I may be missing something. It is really too bad that Bafang has not made it clear exactly what every parameter does and how they are interrelated. I wonder if that information is actually available in Chinese and could be translated. I have a good friend (an MIT electrical engineer) who might be able to find that out.

Good luck with finding more information from Bafang.... There are many that have asked this in the past, some of which sell and support the motors with direct factory and Chinese supplier contacts.
You're on the right track (as far as I can decifer) on how the settings work. But I feel there is some logic going on in the controller that doesn't make the resulting output black and white.
There are many ways to set up the controller and depending on your needs and how you ride there is no one best set of settings. I feel it best to experiment and see what works for you as I ended up far away from the available .el files though they did serve a purpose in helping to understand settings.
So... I understand the current% setting as the available power that can be applied but tempered by where you are in the corresponding speed% setting.
So at a setting of 50 for both it will apply up to 50% of available current (set by the global current setting at the top of the page) to get the motor to reach 50% of motor speed (a factory set number) So when first starting to pedal it will ramp up and apply the full 50% but as you draw closer to the 50% speed setting it will start to curve down the current to 0. Road speed does factor into the equation as I feel it acts sometimes differently at higher speeds but I've found explaining it illusive.

 

[DuncanC]

Thanks Al. I’ve already asked my Chinese electrical engineer with many contacts overseas to explore contacting Bafang. Within the company there must be documentation of the controller parameters at least in Chinese. If anyone can tease that out he can and then shed some light on what the parameters do without speculation or personal experience. The main problem being interaction between parameters that may not be apparent. Anyway I’ll keep reading and sorting things out as I go. It is an interesting challenge and puzzles of all kinds generally intrigue me. Putting a motor up on a bench with variable torque, rpm meter, volt meter and amp meter and a graphical recorder would really make figuring out the motor and controller quite straight forward I think.

 

[AHicks]

Thanks Al. I’ve already asked my Chinese electrical engineer with many contacts overseas to explore contacting Bafang. Within the company there must be documentation of the controller parameters at least in Chinese. If anyone can tease that out he can and then shed some light on what the parameters do without speculation or personal experience. The main problem being interaction between parameters that may not be apparent. Anyway I’ll keep reading and sorting things out as I go. It is an interesting challenge and puzzles of all kinds generally intrigue me. Putting a motor up on a bench with variable torque, rpm meter, volt meter and amp meter and a graphical recorder would really make figuring out the motor and controller quite straight forward I think.

Getting back to the differences between riders, on the bold, I would rather go for a test ride....

 

[Gionnirocket]

The main problem being interaction between parameters that may not be apparent.

This is something I've been saying from the get_go.

 

[Gionnirocket]

I would HIGHLY recommend you bring yourself up to speed the best you can by studying some fairly well written articles as reference material-

Stock Ultra settings and Programming guide

By proceeding with the following you are acknowledging that you are following these instructions carefully and in full. Biktrix is not liable for any changes being made resulting in corruption of t...

support.biktrix.com

I'd have to disagree... The Biktrix article is a poorly written rehash of everything that's been said and misunderstood in the past.
And lumping the Ultra in there is just further proof

 

[AHicks]

We're entitled to opinions. I shared mine, and you're welcome to disagree. I mentioned already I didn't agree with everything they contained, but the parameter explanations are noteworthy if taken in the proper context. I saw no mention of any contents regarding the torque page that might confuse anything....

 

[tomjasz]

That said I may be missing something. It is really too bad that Bafang has not made it clear exactly what every parameter does and how they are interrelated. I wonder if that information is actually available in Chinese and could be translated. I have a good friend (an MIT electrical engineer) who might be able to find that out.

Bafang has never been happy about DIY programming. The new BESST system will eventually lock all users, except for Bafang approved resellers, out of programming.

Some here think it's just a matter of time before someone jailbreaks the firmware. I'm not so sure.

There is a BBSHD dealer's manual, but not a single mention of programming.

 

[tomjasz]

I’ve already asked my Chinese electrical engineer with many contacts overseas to explore contacting Bafang.

If you crack that nut we'll all applaud you!
That said, several very busy BBSxx series resellers haven't gotten Bafang to ever release serial numbers to version changes.

 

[rcooch]

since we're on the topic of Bafang conversion kits i was thinking of converting my barracuda mountain bike to ebike. But i have Questions can the bike handle all the equipment...is it worth the money etc...etc

 

[tomjasz]

Use Google and search brand model and BBS02 and again with BBSHD. Finding build threads can be a huge advantage,

 

[tomjasz]

since we're on the topic of Bafang conversion kits i was thinking of converting my barracuda mountain bike to ebike. But i have Questions can the bike handle all the equipment...is it worth the money etc...etc

Please post a new thread. You'll get far more responses than in a thread discussing BBSxx series controllers.
Do post bike brand, model, and year. If you search, brand, model, year, BBS02 and brand, model, year, BBSHD
Those searches will find any build threads and help plan your build. See also YouTube for installation videos.

 

[Gionnirocket]

Please post a new thread. You'll get far more responses than in a thread discussing BBSxx series controllers.
Do post bike brand, model, and year. If you search, brand, model, year, BBS02 and brand, model, year, BBSHD
Those searches will find any build threads and help plan your build. See also YouTube for installation videos.

He did already... Actually before posting here.
... aka baby Santo