EM3ev explains how BBSxx series motors handle PAS

[tomjasz]

EM3ev wrote, "In our experience, the PAS function of the BBS02 kits work well if they are used in a certain way. We suggest you forget about the PAS level as being an assist level. It is better to consider the setting as a way to adjust the pedalling cadence (speed at which you turn the pedals). Just because it is set to the max setting, does not mean it will pull more power, just because you set it to the minimum setting, does not mean it will necessarily pull less power from the battery (although it will of course tend to use more power and go faster in a higher PAS setting, than a low setting).

The PAS system on the BBS02 kit works like a switch, it does not increase assistance as you pedal faster, it simply applies assist at a certain power and motor speed when it detects the pedals are turning, the speed and max power provided for each PAS setting are programmed into the controller and cannot be changed by the end user. The power provided by the motor when used in PAS mode will increase, if it detects the load has increased (such as changing to a higher gear or approaching a hill), then reduce again as the load goes back to a constant level. As previously stated, the motor speed does not significantly increase or decrease if you pedal faster or slower, and that is why we suggest the PAS level is used to control the pedalling cadence (motor speed).

If you are pedalling hard and can feel you are applying some effort, the motor will automatically do less of the work and the cyclist, will do more of the work, meaning you will travel further on a charge. It is simple, you control how much effort you want to apply, by either pedalling harder, or with less power, so therefore letting the motor do more of the work. Use your bikes gears properly, as you would without motor assist. Select the PAS level so the motor turns at the speed you like to pedal, apply as much or as little effort as you want, use your bikes gear system to fix the speed at which you want to travel on the road, do not control road speeds by just the assist level, use the gears too. Don’t pick an overly high gear on the bike, then pick a low assist level and think you are using less power. You will be operating more efficiently, if you choose an appropriate gear, to allow the motor to spin at a moderate to fast speed (this is especially true on hills).

Just because the motor is strong and can pull the highest gear, does not mean you are using the system in the best way. Making the motor work hard at low motor speeds (speed at which the motor turns or pedalling cadence) risks overheating the motor and blowing the controller, and ultimately, motor failure. The kit works better if the motor is spinning at a reasonably high speed, not labouring at a low rpm in a high gear. Trying to use a high gear whilst going up a steep hill is a great way to blow the controller and overheat the motor. If the bikes gearing is too high to allow the motor to spin at a reasonable speed, it is suggested you change to a smaller chainwheel, or change the freewheel/cassette, so that the lowest gears are low enough to allow the motor to spin at a moderately high rpm whilst travelling up hills.

If you are travelling at high speeds, you will use more power than if you keep speeds lower (as speeds get significantly over 20mph/32kmh, the power requirements go up very significantly). Use a combination of the bikes gear system and the PAS level, to pick a suitable road speed (a moderate speed, such as 25-32km/h is efficient, travelling much faster will reduce range significantly) and pedalling effort, so you are making the most efficient use of the motor and human effort combined, and that will help you get the best range from your battery.

Alternatively, you can just use the throttle and let the motor do the work, but be aware that as speeds increase, the power required to cover a given distance also increases and as speeds get to 25mph (40km/h) plus, the power requirements increase massively. When using throttle only, to travel up steep hills, it is even more important than ever, to pick an appropriate gear, so the motor is turning at a reasonable speed, labouring up steep hills in a high gear is very likely to eventually damage the motor. The bottom line is this; the bike has gears to help the cyclist make the best use of the available power. Just because you have a strong motor, does not mean you shouldn’t still use the gears to make the best and most efficient use of the available power.

 

[Mike_V]

Oh Thanks for this informative well written explanation of our hard to describe shared and complex PAS experience.

 

[K PierreR]

I now have better than 12,000 miles (20,000Km) on my BBSHD equipped bike and for the most part, I agree with everything in the article. It takes a surprisingly long time to reprogram your sub conscious mind to accept Bafang PAS. For me, that was about 6,000 miles (10,000Km). You can intellectually understand it from this article and if you are thinking about it, do a fine job. The problem comes in when not thinking about it which is most of the time.
I subconsciously increased the amount of power I was applying to the pedals according to what was programed into my mind. If I hit a hill, I pedaled much harder. If I went fast, I pedaled much harder. Well Bafang PAS will let you be a dumb ass and do all the work. That is why people naturally want torque sensing. PAS is really designed for people whom use a bike for utility on a daily basis which is most of Asia. I will say this. Once you reprogram your mind for PAS, you will not really want the torque sensing bike.

Let me explain. If you are older and most of these forum are comprised of older riders, you can tailor your ride to fit your energy levels and plan any trip you want. PAS can be used as a therapy bike or used for warm up without much stretching. At the start of a ride and at the finish of a ride, I will drop the seat post and pedal through at near zero pedal pressure. That takes my knees and ankles through the full pedal stroke to loosen up. You can't do that with torque sensing, you only have throttle to put in next to no effort. You can also plan a further trip with plenty of hills and still pedal all of it for the same reason. You can tailor as much work as you want and when your energy starts to wan, you can get back home. A true class one very versatile bike is the result.

Case in point. The bike group that I am in has a mix of PAS, Torque sense and Dino/analog bikes. From our ride starting point if you go west, you will be on mostly flat terrain. If the Dino/analog crew show up, west it is. If you go east there is 5 miles of climbing and 5 miles of descending. The climbs are brutal but worse on the return trip and usually with a headwind. The pavement is new and the riding more scenic. When only the e bikes show up, the riding is often east. The PAS bikers are always up for the ride with enthusiasm. The torque sensed bikers are often reluctant and get very winded. About 50% of the time, the torque sensed folks don't care to go east and we go west. Oh joy if only the PAS group shows up. I built all of the PAS bikes with the exception of two. All are Bafang mid drives. All but one of the torque sensed bikes are mid drives too.

If you want to go on an epic ride that you know will exceed you energy levels to assist, only a PAS bike will let you do it. You will end up being a class 2 motorbike on a torque sensed bike. Of course, all bets are off if you push to the limits of the battery. You put in a lot of work to get a lot of range from limited battery capacity. I found true freedom with a big battery bank.

I also find Bafang nice because you can program them. At the start of the season, I usually program the levels for our group to include a bit more assist. As they get better fitness, we program them down a bit so the speeds stay consistent with the Dino/analog riders and everyone is happy.

This is of course, all my opinion and nit picking will be ignored. Grin

 

[Gionnirocket]

The PAS system on the BBS02 kit works like a switch, it does not increase assistance as you pedal faster, it simply applies assist at a certain power and motor speed when it detects the pedals are turning, the speed and max power provided for each PAS setting are programmed into the controller and cannot be changed by the end user.

A bit confused here... What is the BASIC TAB then in the programming?

The power provided by the motor when used in PAS mode will increase, if it detects the load has increased (such as changing to a higher gear or approaching a hill), then reduce again as the load goes back to a constant level. As previously stated, the motor speed does not significantly increase or decrease if you pedal faster or slower, and that is why we suggest the PAS level is used to control the pedalling cadence (motor speed).

Agree with this especially and pretty much everything else.

 

[Gionnirocket]

I now have better than 12,000 miles (20,000Km) on my BBSHD equipped bike and for the most part, I agree with everything in the article. It takes a surprisingly long time to reprogram your sub conscious mind to accept Bafang PAS. For me, that was about 6,000 miles (10,000Km). You can intellectually understand it from this article and if you are thinking about it, do a fine job. The problem comes in when not thinking about it which is most of the time.
I subconsciously increased the amount of power I was applying to the pedals according to what was programed into my mind. If I hit a hill, I pedaled much harder. If I went fast, I pedaled much harder. Well Bafang PAS will let you be a dumb ass and do all the work. That is why people naturally want torque sensing. PAS is really designed for people whom use a bike for utility on a daily basis which is most of Asia. I will say this. Once you reprogram your mind for PAS, you will not really want the torque sensing bike.

Let me explain. If you are older and most of these forum are comprised of older riders, you can tailor your ride to fit your energy levels and plan any trip you want. PAS can be used as a therapy bike or used for warm up without much stretching. At the start of a ride and at the finish of a ride, I will drop the seat post and pedal through at near zero pedal pressure. That takes my knees and ankles through the full pedal stroke to loosen up. You can't do that with torque sensing, you only have throttle to put in next to no effort. You can also plan a further trip with plenty of hills and still pedal all of it for the same reason. You can tailor as much work as you want and when your energy starts to wan, you can get back home. A true class one very versatile bike is the result.

Case in point. The bike group that I am in has a mix of PAS, Torque sense and Dino/analog bikes. From our ride starting point if you go west, you will be on mostly flat terrain. If the Dino/analog crew show up, west it is. If you go east there is 5 miles of climbing and 5 miles of descending. The climbs are brutal but worse on the return trip and usually with a headwind. The pavement is new and the riding more scenic. When only the e bikes show up, the riding is often east. The PAS bikers are always up for the ride with enthusiasm. The torque sensed bikers are often reluctant and get very winded. About 50% of the time, the torque sensed folks don't care to go east and we go west. Oh joy if only the PAS group shows up. I built all of the PAS bikes with the exception of two. All are Bafang mid drives. All but one of the torque sensed bikes are mid drives too.

If you want to go on an epic ride that you know will exceed you energy levels to assist, only a PAS bike will let you do it. You will end up being a class 2 motorbike on a torque sensed bike. Of course, all bets are off if you push to the limits of the battery. You put in a lot of work to get a lot of range from limited battery capacity. I found true freedom with a big battery bank.

I also find Bafang nice because you can program them. At the start of the season, I usually program the levels for our group to include a bit more assist. As they get better fitness, we program them down a bit so the speeds stay consistent with the Dino/analog riders and everyone is happy.

This is of course, all my opinion and nit picking will be ignored. Grin

I totally agree... But it only took me a few hundred miles to figure it out
I have mine programed to increase my speed with each PAS level up with near the same power levels.
When cycling I try to maintain different speeds depending on road conditions and by selecting the correct PAS the BBS02B applies the power to help me maintain it. Proper gear selection remains unchanged from riding a non ebike. A head wind or hill it will increase power.. and conversely the opposite going down hill will decrease power output by the motor.
As you go faster in any gear, the pedaling becomes easier and I require less assistance from the motor. I think it works quite well in this manner.

 

[K PierreR]

I totally agree... But it only took me a few hundred miles to figure it out
I have mine programed to increase my speed with each PAS level up with near the same power levels.
When cycling I try to maintain different speeds depending on road conditions and by selecting the correct PAS the BBS02B applies the power to help me maintain it.

I had it figured out from reading the first time I rode it. That does not mean I didn't catch myself pedaling to hard with my mind treating it as a Dino/analog bike. That took about 6,000 miles before that no longer occurred.

I started out programing different speeds and power levels. Then I progressed to different speeds with higher power levels to act as a cruise control. Now I basically have the first six levels programed to a max of 20 mph and progressive but not equal power level increases. Power tops out about 680 battery watts at level 6. 7 and 8 are progressive class 3 and jump to a motor output max of 750 watts. Level 9 is bear, dog, thunderstorm approaching mode and hard on gear mode, the max, a big jump

 

[Gionnirocket]

I had it figured out from reading the first time I rode it. That does not mean I didn't catch myself pedaling to hard with my mind treating it as a Dino/analog bike. That took about 6,000 miles before that no longer occurred.

I started out programing different speeds and power levels. Then I progressed to different speeds with higher power levels to act as a cruise control. Now I basically have the first six levels programed to a max of 20 mph and progressive but not equal power level increases. Power tops out about 680 battery watts at level 6. 7 and 8 are progressive class 3 and jump to a motor output max of 750 watts. Level 9 is bear, dog, thunderstorm approaching mode and hard on gear mode, the max, a big jump

The variables and rider needs are many and diverse.
I just wish Bafang would have put out a clear and well translated users manual with regards to programming. After all this is a DIY kit!

 

[AHicks]

I'm disappointed that this wasn't posted in the "Discussion by brand and user forum - Bafang". so that it could be referenced fairly easily later on. In the general forum it's going to be buried quickly.

Myself, I love reading about other's thoughts on the topic. Seems like I frequently pick up little pieces that better my understanding! I don't think many folks have a real good understanding of all of the little pieces that make these things tik.....

Maybe we could get it moved?

 

[K PierreR]

The variables and rider needs are many and diverse.
I just wish Bafang would have put out a clear and well translated users manual with regards to programming. After all this is a DIY kit!

Let me translate for you:
Messages instruction clear of Bafang also I want. There you go.

 

[AHicks]

The variables and rider needs are many and diverse.
I just wish Bafang would have put out a clear and well translated users manual with regards to programming. After all this is a DIY kit!

DIY kit out of necessity? Trouble is, too many people don't realize the potential available to them and ride them as-is. It's very difficult to have a real comprehensive understanding of everything going on in there without a LOT of research. And that's just the beginning. The Ultra compounds the issue...

 

[Gionnirocket]

DIY kit out of necessity? Trouble is, too many people don't realize the potential available to them and ride them as-is. It's very difficult to have a real comprehensive understanding of everything going on in there without a LOT of research. And that's just the beginning. The Ultra compounds the issue...

I'm sorry Al, but you lost me
The bbsxx is an add_on motor to a non ebike. Necessity? I don't know.
There shouldn't be the need for a lot of research if the manufacturer provided an explanation of the controller programming values and how they interact. I never understood what the secret is and how sharing this information wouldn't increase their sales and popularity.

 

[Gionnirocket]

Let me translate for you:
Messages instruction clear of Bafang also I want. There you go.

You lost me as well... Sounds like chinglish translation

 

[AHicks]

I'm sorry Al, but you lost me
The bbsxx is an add_on motor to a non ebike. Necessity? I don't know.
There shouldn't be the need for a lot of research if the manufacturer provided an explanation of the controller programming values and how they interact. I never understood what the secret is and how sharing this information wouldn't increase their sales and popularity.

What I meant was, included in the DIY is the flexibility to personalize all of the available settings. We both know how much our riding habits/requiremets differ. There is no "one size fit's all". I'll be the first to agree that a comprehensive explanation is not available - yet.

 

[K PierreR]

You lost me as well... Sounds like chinglish translation

Ha Ha, I did not lose you. Some day Bafang will figure out the American Market and business practices. The Chinese are doing way better on that front than those from India.

 

[Gionnirocket]

What I meant was, included in the DIY is the flexibility to personalize all of the available settings. We both know how much our riding habits/requiremets differ. There is no "one size fit's all". I'll be the first to agree that a comprehensive explanation is not available - yet.

That's for sure...and hence my gripe about the lack of Manufacturer Instructions
I have several and various pieces of equipment that can be programmed and all came with the manufacturer instructions on settings and the default setup explanation. The fact that we have different requirements makes it all the more important. To me saying that this is DIY and therefore you must research it yourself is Booooolshit! My two cent.

 

[tomjasz]

Maybe we could get it moved?

Reported and requested move to "Discussion by brand and user forum - Bafang"

 

[tomjasz]

sharing this information

I've tried for years to get basic information from Bafang. There are no accessible serial numbers to sort which version of firmware, which motor, and which controller a user has.

I remember only too well the week Bafang started shipping 02B, and 01B versions. No announcement. Luna was the largest North American reseller and couldn't get that info. I and others have asked for years to have a complete parts list. Forget about a parts schematic!

That said, I still like my BBSxx series motors. For me the best mid-drive kits available.

 

[m@Robertson]

There shouldn't be the need for a lot of research if the manufacturer provided an explanation of the controller programming values and how they interact. I never understood what the secret is and how sharing this information wouldn't increase their sales and popularity.

You have to take into account the sheer size of Bafang, and its focus on the utility rider market in the Far East. Nuanced conversations like these are to them like the Chinese language is to us - utterly foreign. We're still small potatoes to them as a marketplace. In their world, where they sell the vast majority of their production output, the factory settings are what everyone should use, without tinkering. Hell... EVERY settings adjustment tool out in the wild for a BBSxx was created by an outsider. Bafang has never wanted these details to be available to end users, and at times has made decisions that are considered good for its target audience and catastrophic for the Western DIY user (I'm thinking particularly of the PAS/throttle override issue with the firmware a couple of years ago that I think still affects almost all of the HD units not sold by Luna). More recently, it seems the motors not from Luna have an issue that deprecates/prevents the full use of a 52v battery.

We get what we do out of the Bafang motors not because the factory approves of what we're doing. We get these benefits despite them. If you've ever tried to do any tuning to a late model Mopar hot rod its exactly the same issue where the mfr (first DaimlerChrysler, then FCA and now Stellantis) deems the software as its intellectual property and the end users say 'screw you' and figure out how to do it anyway.

 

[m@Robertson]

I have often described the Bafang PAS system as 'counterintuitive' and 'opaque' and this thread just reinforces that. You can't look at it as a cyclist if you are thinking old school. You have to come at the Bafang system from a completely fresh perspective - its a new animal and you have to start learning how it works from scratch. Do that and you'll figure it out get desirable results.

I also have said that if using the system properly, you wind up with an exercise machine that goes places. @K PierreR's observation that Bafang's PAS is aimed at utility riders and not Western recreational riders is spot on, as is his discussion of it enabling a 'therapy' bike. Something that provides a level of flexibility that torque sensing bikes cannot mimic or even approach. I totally concur that - once you make the mental shift on how Bafang's system is best used - you likely will not want any part of torque sensing. I certainly don't, and I bought one (then sold it) to make sure I wasn't imagining that prejudice.

In talking to eMTB riders though, they are in a totally different world when it comes to what they want out of PAS. I've described how - when cadence increases, I have the motor set up to decrease assistance since I don't need help (as evidenced by my ability to maintain high cadence). But thats the last thing eMTB riders want and I understand why. If you are hamstering by necessity up a steep and maybe even a loose incline, the last thing you want is for the motor to decide its time to cut back the power.

There are SO many BBSHD users and evaluators who have no idea how different these motors can behave with the right settings. Especially bearing in mind the large number of production ebikes that use them; not just the DIY specials.

 

[AHicks]

That's for sure...and hence my gripe about the lack of Manufacturer Instructions
I have several and various pieces of equipment that can be programmed and all came with the manufacturer instructions on settings and the default setup explanation. The fact that we have different requirements makes it all the more important. To me saying that this is DIY and therefore you must research it yourself is Booooolshit! My two cent.

Manufacture's instructions could be even more frustrating than nothing. Think incomplete AND written in broken english.

I KNOW it's possible for them to make a comprehensive set available, but that's a pretty rare case...