Speed vs Power – PAS programming choices

HighPockets

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There has been a lot of discussion related to this so I think it deserves its own thread.

Here is the issue as I see it;

Bafang has gone to some lengths to make the result of the PAS settings what they think their customers want. For many they have succeeded. Basically it is a what I call speed mode, a kind of loose cruise control, achieved by having speed limits at each PAS level and decreasing power at higher cadence (pedal RPM). Cruise is good for the person who tends to stay at the same effort and cadence and is reluctant to row the gear shift lever, but it encourages one to stay at low cadence and you never really know how much assist you are getting.

…but we do not all have the same needs, and cruise is inappropriate and confusing for more experienced riders who know what power assist they want, need controls for setting it and like to know what they are getting. This is not just a matter of loosening up controls for the hotdogs that want higher speed and more power. Power mode would be much more understandable in training and more appropriate for making up a constant difference in power when riding with powerful non-e riders.

Electrical power (Watts) equals volts times amps, so each PAS setting would be an amps setting, delivering the same amps no matter what the bicycle speed or pedal RPM.

The dream is a choice at setup of whether the PAS settings would be for speed or power, but for now the closest we can do to get power mode is to set all the PAS speed limits to 100% of the global speed limit and change the cadence level at which the power decrease starts to the highest RPM possible (Current Decay = 8). Unfortunately it is not currently possible to set the power decrease to never.
 

Vinz

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You have certainly given this a lot more careful thought than I.
I agree that the Bafang PAS system is a form of cruise control; just an on/off, yes/no approach, with adjustable current limits. And I agree that setting PAS speed levels to 100% can somewhat simulate a power mode.
But I haven't experimented with, or even studied Current Decay at all, and cannot comment on how that would affect the riding experience.
Also, I don't really understand the meaning of 'speed' in regards to programming the motor. It's easy to think that it simply means bike speed, but I read somewhere that it really means motor speed. If this is so, then shifting gears can become a great asset to the riding experience. I think that's the major advantage of a mid drive system.
Seriously, I'm no expert here. In fact, before I got my pedal bike in June/2020, I hadn't been on a bike in over 30 years. I just converted the bike in April/2021 to a BBS02 system. And since I'm a newbie, I adapted quite well to how it operates. Hey, 5K miles in 15 months isn't too shabby for an older guy.
Final thought...
I wish there was someone with a clear understanding of the Power Mode adjustment, the one that can be set from "Undefined", to 100. It seems like it could have some real value for us. But from what I have read, it seems to make no difference no matter how it's set, and there's really no discussion about it.
 

J T M Jansen

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I find the BBS02B 750w with a 48v x 17.5AH battery works in all situations, smooth control and smooth assistance at any speed with a throttle boost for the hill work, in BASIC Tab mine is set Pas 1-9 (10-100% current and 100% speed all the way) In PEDAL ASSIST TAB, KEEP CURRENT is set to 80 and START CURRENT to 20 , in THROTTLE tab, Throttle is set at PAS 5 which gives me 50% current, but could be set to any pas, and MODE is Current..
That all makes it smooth acceleration and smooth power assist where you want it, Mostly we cruise at 20-25kph (but can easily cruise at 35kph or more) with pas-1, maybe pas-2 into wind and on hills we just punch the throttle, its a 9 speed giant btw, and we are in our 70s also
 

Hoggdoc

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If you are referring to the START CURRENT, then that is so I get smooth acceleration. The best explanation and understanding of each BBS setting Ive ever seen in print is by Geil, at https://edrivenet.com/bafang-programming/
No I was speaking of your statement where you said you limited the pedal assist current to 80%, I totally understand why you would limit Startup current. Some controllers call that setting soft start.
 

J T M Jansen

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Ah, okay, called "Keep current" in bafang controller, it will decide to which current your motor will drop when it reaches a high rate. this only engages when you are pedaling at a high rate (and you have reached a constant speed). Then it will drop to the percentage you set here, eg; 80 percent of the current that is assigned in the selected assist level. So if you set this setting really low, then the motor will assist less when you have reached a constant speed. If you set this setting higher, it will assist more when you have reached a constant speed.
I use 80% because this gives plenty of power when a constant speed is reached. It nicely compensates for my pedaling power. If I want to pedal more and save more battery at a constant speed, set it to 60%.
 

Hoggdoc

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Ah, okay, called "Keep current" in bafang controller, it will decide to which current your motor will drop when it reaches a high rate. this only engages when you are pedaling at a high rate (and you have reached a constant speed). Then it will drop to the percentage you set here, eg; 80 percent of the current that is assigned in the selected assist level. So if you set this setting really low, then the motor will assist less when you have reached a constant speed. If you set this setting higher, it will assist more when you have reached a constant speed.
I use 80% because this gives plenty of power when a constant speed is reached. It nicely compensates for my pedaling power. If I want to pedal more and save more battery at a constant speed, set it to 60%.
Got it. How do they control max speed, is it limited to what the bike can do or 28mph?
 

J T M Jansen

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Max ASSIST speed can be controlled by Motor Controller and/or the handlebar display unit, normally mine is set to handlebar display so its easily changed if required mid ride. but in max THROTTLE speed it is set in Bafang controller to 40kph which is highest setting.
As a matter of interest my "assist" levels 1-9 are all set to 100% so i I have no speed limit in any "assist level", only limited by my physical gear (9 speed) selection and my legs, :)
 

Hoggdoc

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Max ASSIST speed can be controlled by Motor Controller and/or the handlebar display unit, normally mine is set to handlebar display so its easily changed if required mid ride. but in max THROTTLE speed it is set in Bafang controller to 40kph which is highest setting.
As a matter of interest my "assist" levels 1-9 are all set to 100% so i I have no speed limit in any "assist level", only limited by my physical gear (9 speed) selection and my legs, :)
OK wonder why the limit is set so low? Is it the law in NZ?
 

J T M Jansen

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lol, NZ ebike speed limit is 25kph on road or cycleway, (max 300w). much like Europe i think. However there is a option to bypass the motor limit and point it at the Handlebar display control, which ofcourse tops out at 99KPH :)
 
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