Speed pulsing on BBS02

rammike

New Member
Region
Canada
I recently added a BBS02 to my old Giant 'Commuter' 26" bike. It was surprisingly easy and worked out really well. I use a 48V/17.5Ah battery. My objective was to have a bike I could ride with a 15 km/h effort and go 25 km/h for at least 80 km. My brief tests (still cold here in Ontario) indicate that this should not be a problem with efficiency running around 6-8 wh/km in the general area I do most of my riding. The issue I have is a 'pulsing' of power delivery that results in the constant speed cycling from 22 to 25. (Some settings: Limited Current:18A, PAS1-9:10%-100% Current/all 100% Speed, Max Speed 25, Current Keep:80%.) The PAS has no real effect other than increasing the rate of the pulsing. Assist drops to 0 at 25 and starts up again at 22. Can anyone recommend controller settings that may reduce this speed pulsing? I have an Eggrider so can make and test setting changes very easily. Thanks.
 

Bubba zanetti

Active Member
Region
Canada
City
Trail, BC
Check your cadence sensor alignment. make sure. The spoke magnet is aligning with sensor.
 

rammike

New Member
Region
Canada
I don't believe I have access to the cadence sensor as it is internal. The speed sensor you mention seems to be working fine - no dropouts in reported speed at any time. I will check though......
 

rammike

New Member
Region
Canada
Thanks to another poster it appears that this pulsing is inherent in the design of the controller. He suggested removing the speed limit and just adjusting power to give the assist needed to maintain the target speed with the desired effort level. This should eliminate the pulse and glide effect of the speed limit approach. I will be trying this out as soon as the weather improves.
 

PedalUma

Well-Known Member
Region
USA
You can also lie to the programing and tell the bike that is has 40% smaller wheels, setting the display to Km, so it will numerically display Mph. "30Km" will actually be 30Mph, 40% faster.
 

K PierreR

Well-Known Member
Region
USA
With you settings it will pulse for sure if you have the max speed set at the speed you are trying to go. That is because it starts to reduce power sooner when it gets near the max speed. Set you max above 25 and program a few closely spaced power levels that will maintain roughly the 25 kph 10% jumps are to much of a power increase. I say program a few around it because you will go up and down hill. You change the assist at the same time you would the gears. Probably set your max around 27-28.
You can increase the point of reduction from 80% to 90% and it will help. If you increase to 100% it will likely surge from constant on-off action.
You have speed limits in both the programing and the set point on the display. Its the set points in the programing that must be increased.
 

rammike

New Member
Region
Canada
With you settings it will pulse for sure if you have the max speed set at the speed you are trying to go. That is because it starts to reduce power sooner when it gets near the max speed. Set you max above 25 and program a few closely spaced power levels that will maintain roughly the 25 kph 10% jumps are to much of a power increase. I say program a few around it because you will go up and down hill. You change the assist at the same time you would the gears. Probably set your max around 27-28.
You can increase the point of reduction from 80% to 90% and it will help. If you increase to 100% it will likely surge from constant on-off action.
You have speed limits in both the programing and the set point on the display. Its the set points in the programing that must be increased.
Good suggestions! I will try them out for sure.
 

Gionnirocket

Well-Known Member
Region
USA
City
Y. O.
Thanks to another poster it appears that this pulsing is inherent in the design of the controller. He suggested removing the speed limit and just adjusting power to give the assist needed to maintain the target speed with the desired effort level. This should eliminate the pulse and glide effect of the speed limit approach. I will be trying this out as soon as the weather improves.
Good advice given in prior posts.
I've found that a Keep Current of 85 seems to help.
Also as suggested increasing your global top speed helps, I have mine set to 28mph but my typical ride top speed is below 20mph.
And lastly it feels like certain speed/cadence/ PAS combinations do it more... so depending on your upcoming terrain shift up or down to slightly vary the speed /cadence... I typically land where the motor is contributing 0 -3 amps.

Another approach which I believe is what you were referring to here is to set all PAS speed limits to 100% and then incrementally increase current in each PAS. This does allow for smoother motor response but you loss the efficiency and convenience of automatically adjusting power applied as terrain/wind changes. Using this approach I found that I constantly had to adjust my PAS setting and I used more battery so I prefer the traditional approach to PAS settings... YMMV.
 

rammike

New Member
Region
Canada
Thanks for the feedback.
I have tried many combinations and it seems to have improved to the point where I don't think about it any more - maybe I'm just used to it now. I have the speed set at 26 and just ride adjusting power and gear selection as required to maintain the effort that I want to make. I generally ride at about 5-7 wh/km average. I have power going 10-100% all at 100% speed. I normally am in the 2-4 (3-6A) range. I'm back using the 500C as my Eggrider broke. Actually I only use the PAS buttons and never look at it - I have my old speedo and a wattmeter and it gives me all the data I want and is much easier to read!
 

Gionnirocket

Well-Known Member
Region
USA
City
Y. O.
Thanks for the feedback.
I have tried many combinations and it seems to have improved to the point where I don't think about it any more - maybe I'm just used to it now. I have the speed set at 26 and just ride adjusting power and gear selection as required to maintain the effort that I want to make. I generally ride at about 5-7 wh/km average. I have power going 10-100% all at 100% speed. I normally am in the 2-4 (3-6A) range. I'm back using the 500C as my Eggrider broke. Actually I only use the PAS buttons and never look at it - I have my old speedo and a wattmeter and it gives me all the data I want and is much easier to read!
I agree... the Eggrider is not practical for everyday use. It's Ok for testing, adjusting settings and to aid with troubleshooting problems.
I much prefer my 860c display that is center placed over the stem and can be seen in all light conditions... and with the separate buttons placed near the hand grip, I can easily toggle PAS up/down without looking.
The 100% speed in all PAS does make the motor response more smooth. But for me with many changing hills, I had to adjust PAS often and used more battery. So I went back to incremental speed up the PAS scale.
There is no perfect solution... But you can make it very enjoyable...
 

rammike

New Member
Region
Canada
Enjoyable is indeed the word I would use. As an 'older' rider who has lost the ability (or is it will) to take those long rides on a nice day, this thing makes all the difference in the world. I don't turn around now when I see a big hill and can just head out not worry about getting home. I know I have at least 100km in the battery. It works great at 25-26 or so but 30 really seems to make a difference - is just uses a lot more power. No matter I am fine at that speed anyway. I read all these claims about 32 (20mph) and 45 (28mph) and they just don't seem practical to me - just takes way to much power to maintain those speeds and range would really suffer. So yes, bike riding is enjoyable again....