New Bafang Crank-Drives

[Ken Taylor]

What is the easier/quick way to limit the power to 20Amp as my Lifepo4 battery will not like 25a?

This is a question for the programming thread but the answer is:-

I've tested that this setting works.

As an aside and because I see you also have a 350W BBS01. You can make a 350W BBS01 the same as a 250W BBS01 by changing the Limited Current (A) from 18 to 15 or vice versa. The only other difference is the numbers engraved on the bottom of the motor.

 

[bgt]

for information ...controller
and new connectors

Could you check what the brand of the capacitores is? What are the values written on them?
Why 8 x TO220 chips? Are 6 powermosfets for the drive and the other 2 voltage regulators(switched mode)?

 

[0utrider]

I finally got around to making an Anderson powerpole extension cable and replacing the seat on the Frankenbike.
After properly programming the head unit for my wheel size and changing it to have 9 assist levels, I took it for a short ride through downtown San Antonio to clear the cobwebs off the frame. I think I finally have an interim solution for securing the battery until I can find or make an enclosure and it held just fine with a padded matt between the rack and cells to absorb the impact being held down with straps over another layer of padding both hold the battery and help with the shock. The pack did not budge a millimeter and I was hitting bumps and dropping off curbs without the fear I had before. No chain drops this time and only a couple times where the derailleur shifted when I cranked hard on pedals. I blame the shifter cables being partially pinched by the rack mounting straps keeping it from proper alignment.

Bafanging it with Frankie at the Alamo

I've certainly changed my mind after this ride about pedal assist. I actually had a great time in setting 1 and 2. It pedaled very well but I still preferred to start with no assist and only kick it to 1 after I was already moving. What the hell, it saves battery. Top speeds with original programming kissed 28 to 32 depending on whether there was a slight grade up or down so this thing is plenty fast for my urban darting. This thing is SOOOO quiet and the only thing anyone notices is the giant battery pack. My thoughts? I consider it a success which will only improve as I tune in the components and finished out the bike.

This is the route I took. Just 10 miles but I had a scant 40 minutes to get home before taking the family out dinner.

10 Mile Route

I can't wait until this coming weekend!

 

[Warren]

0utrider,

"I've certainly changed my mind after this ride about pedal assist. I actually had a great time in setting 1 and 2."

Congratulations! You are a bicyclist. Motorcyclists don't get pedal assist.

 

[John Bozi]

Outrider,

one of the great advantages of a mid drive are sprung weight and centering weight between the wheels.

you have huge triangle real estate for that battery that would make handling a dream.

 

[0utrider]

Outrider,
one of the great advantages of a mid drive are sprung weight and centering weight between the wheels.
you have huge triangle real estate for that battery that would make handling a dream.

I've definitely have given it plenty of thought. Truth is that the triangle area is a bit smaller than the photo perhaps illustrates. What little space exists is eaten up with that rear support “shock” spring.
Any solution with the existing battery requires that I disassemble the pack and come up with some interesting geometry. Three sets of 4 cells strips in a triangle formation capping the down tube and two strips of 2 cells running tandem under the top tube is what I’m thinking. Unfortunately this would be a semi-permanent installation which is bad or good depending on the situation. Another solution would be getting a lower amp bottle mount battery for regular use and use the big battery for distance rides but that would cost more money. I’m sure something will come up. Anyways I’m ok with the current situation as the bike is unwieldy for me and not too different from my regular bike with the big pannier bag hanging on the rack loaded with a bunch of junk.

 

[0utrider]

Motorcyclists don't get pedal assist.

Yes they do! It's called a kick-starter!

 

[RayGo]

I think I found a tool that will work on both the M33 locknut and outer locknut cover.


The measurements look about right for the outer cover. I'm hoping it works since the tool is only about $7 on e-bay from China. I just ordered one so I'll post once I get the tool and test it.

I was able to find a spanner/lockring wrench for a reasonable price, but the Parktool BBT-19.2 that I think fits the outer lockring costs about $20. Rather expensive for 2 tools that I don't plan to use too often.

I'll be posting my bike build and comments shortly. The bike is setup and running but the BBS02 did not come with the magnetic spoke sensor, so I'm stuck with error code 21 and can't change Pas settings.

The default BBS02 program setting are pretty bad. I did manage to change the programming to allow Pas 0 to give me full throttle and that was fun. So now I'm waiting for my new speedmeter with its spoke magnet to fix the problem.

 

[Warren]

0utrider,

"Yes they do! It's called a kick-starter!"

Forty four years ago, when I quit MCs and went back to bicycles, practically all bikes were kick-start. As far as I know, no road MCs are now. Most folks riding don't look like they could kick one over. I remember my 98 pound buddy lived on a hill. On cold mornings, if he couldn't bump start his Sportster down the hill, he would call me up and I would ride my Bonneville over to his place and kick start it for him. Damned little chrome bowler hat air filter would leave a bruise on the inside of your thigh.

 

[0utrider]

Forty four years ago,

A couple of years back I bought a KLR 650 and was sure as surprised that I didn't notice the lack of a kickstarter until I went to start it to take it home from the dealership. "Where the h*ll is the kickstarting lever?" I asked the sales guy. That's where I learned that they don't come with them anymore! HA HA HA!!!

 

[John Bozi]

Outrider,
one of the great advantages of a mid drive are sprung weight and centering weight between the wheels.
you have huge triangle real estate for that battery that would make handling a dream.

I've definitely have given it plenty of thought. Truth is that the triangle area is a bit smaller than the photo perhaps illustrates. What little space exists is eaten up with that rear support “shock” spring.
Any solution with the existing battery requires that I disassemble the pack and come up with some interesting geometry. Three sets of 4 cells strips in a triangle formation capping the down tube and two strips of 2 cells running tandem under the top tube is what I’m thinking. Unfortunately this would be a semi-permanent installation which is bad or good depending on the situation. Another solution would be getting a lower amp bottle mount battery for regular use and use the big battery for distance rides but that would cost more money. I’m sure something will come up. Anyways I’m ok with the current situation as the bike is unwieldy for me and not too different from my regular bike with the big pannier bag hanging on the rack loaded with a bunch of junk.

Thanks Geebee for putting me onto emax here in Oz (I always prefer paying more but supporting Aussies). I have ordered and waiting.

This is my bike which I will be putting the bafang 750 on.

Only after over a year have I finally fit 4x6s bricks in the triangle with an sheet of aluminium. Not finished but yeah I went to lipo because the headway bms stuff was excellent at living with but sucked for fitting..

Will probably 2015 before I have this all running dual drive because of Xmas holidays...

 

[Tom L]

Outrider have you seen these Headway cell spacers? http://www.headway-headquarters.com/3-hole-spacer-block-40/

Might assist with constructing a pack for the triangle.

 

[0utrider]

Outrider have you seen these Headway cell spacers? http://www.headway-headquarters.com/3-hole-spacer-block-40/

Might assist with constructing a pack for the triangle.

You bet Tom L. I'm considering those to help me rearrange the pack but the geometry issue is still haunting me.
I want to be able to remove it easily for charging indoors at work. So, in the meantime.... I have an el-cheapo idea and will post the pics this weekend.

 

[John Bozi]

Here goes a possibly dumb question.

context: I have never had a mid drive, but have driven a manual car and run a hub motor now.

revs and efficency

With a hub motor I never ever questioned the highest speed my motor could spin, I just took it intuitively to be whatever it couldn't go faster was the best was for the motor.
Obviously slower than that it was not efficient. Not talking road and wind resistance.

With a car you have gauge that is in red when you are revving too high.

Now with a mid drive?

Would running the mid at its highest speed in granny gear (let's say 20kmh) be more or less efficient than running it in another gear at 20kmh?
Would the motor ever over heat when keeping it at 750w 25amps?

 

[Animalector]

I have found with my mid drive it's more about how fast you can pedal (if you're going to pedal). running at max speed in granny gear I think would be easier on the motor, but you won't be able to pedal to keep up.

Anyone else?

Andy

 

[Warren]

Andy,

"running at max speed in granny gear I think would be easier on the motor, but you won't be able to pedal to keep up. Anyone else?"

Don't know what type of mid-drive you have, but I would suggest it is overvolted, or the gearing between the motor, and cranks is too low. Lets say going down a steep hill in high gear, at no load WOT motor speed, the cranks are turning 115 rpm. Nobody but a bike racer could keep up that pace. But on the level, if you shift gears to get your most efficient motor speed, about 80% of unloaded, that's 92 rpm..about perfect. Now lets say you are climbing a steep hill, and gear down to about 50% of no load speed for maximum power. This would be a cadence of 57.5 rpm...pretty good for grunting up hills standing.

Basically, what I am saying is that, by dumb luck, the best range of human cadence, and the best range of electric motor speed is about the same percentage wise.

 

[rscamp]

Here goes a possibly dumb question.

context: I have never had a mid drive, but have driven a manual car and run a hub motor now.

revs and efficency

With a hub motor I never ever questioned the highest speed my motor could spin, I just took it intuitively to be whatever it couldn't go faster was the best was for the motor.
Obviously slower than that it was not efficient. Not talking road and wind resistance.

With a car you have gauge that is in red when you are revving too high.

Now with a mid drive?

Would running the mid at its highest speed in granny gear (let's say 20kmh) be more or less efficient than running it in another gear at 20kmh?
Would the motor ever over heat when keeping it at 750w 25amps?

In the simplest possible terms, select the gear that runs the motor at the most efficient power level. This will be a specific current for a given throttle setting. I think someone on here did some dynamometer tests and found the current at full throttle and max efficiency was somewhere in the range of 17A? Anywho, the reality is since it varies with throttle it is hard to know where you are really at. Be sure not to bog down the motor way below no-load RPM or to load it too lightly. Both cases approach zero efficiency.

 

[John Bozi]

Animalector concept had crossed my mind for a long time. Add to that:

I have 30t front & 11t-28t freewheel (or30 cant remember) I only pedal in 11t 99% of the time unless I am passing pedestrians close on a bike path which then I get slow even further.
30t x 11t sees a comfortable 20-25kmh so you guess I only pedal around take off time mostly or when off road I slow down so its just right.

so

the mid drive I really want for the 0-20kmh mark although I will barely need the pedals as you say the granny will take it up to 20 but I can't pedal in it.

In the end I am guessing choose the sound of the motor around the middle pitch...

 

[Geebee]

Real world results with a BBS01 is that letting the motor spinnout to close to its max revs delivers the lowest power usage, my last ride I used 8 Wh per km with zero pedal assist, I spin the pedals to run the motor but put out no effort, the ride was about 350m climbing, my previous ride used 9.4 Wh per km and the only differences were that I allowed the motor to spin a bit faster, had a strong head wind and was faster this time, which means I should have used more power.
A normal bike will most likely not get that low a WH as I was riding a very light, low racing recumbent trike.

 

[Jazzman56]

Hi Guys,

(A bit random...)
I'm looking at getting a Bafang BBs02 Middrive system for my daily commute
Is there anyway of getting the Bafang to fit in a 86mm BB such as on many newer Giant Dual suspension MTB such as --> http://goo.gl/KbcnuR
--> I have access to a Lathe/Welding/Machining etc.

Jazzman56

 

[Warren]

Jazzman56,

You might want to check with California Ebikes.

http://california-ebike.com/

He does a 100 mm bottom bracket conversion.

https://www.youtube.com/watch?v=Yc2ZI2vuqng

https://www.youtube.com/watch?v=GjK2CretaaI

 

[John Bozi]

More questions after reading the manual.

1. Is the only on off switch on the display unit? Does turning it off, turn off the battery draw and any power to the motor?

I ask this as I won't be using the electric brakes and need some kind of safety option if power gets stuck on...

do I need some kind of on off switch between the battery and controller? so that I don't need to disconnect the battery all the time?

Is there any draw on the battery when the display is switched off? I don't want my lipos catching fire...


2. I just realised something... since I will be putting this mid drive to work with a hub motor... there may be some interference with the magnet on the spoke for the speed sensor coming from the massive amount of magnet activity in the hub motor...

Is the speed sensor a must if I don't care about the speed reading? I'm guessing yes, because error codes would probably cut motor power.

 

[cjh]

Hi Guys,

(A bit random...)
I'm looking at getting a Bafang BBs02 Middrive system for my daily commute
Is there anyway of getting the Bafang to fit in a 86mm BB such as on many newer Giant Dual suspension MTB such as --> http://goo.gl/KbcnuR
--> I have access to a Lathe/Welding/Machining etc.

Jazzman56

With a little commitment it might be possible :wink:

http://endless-sphere.com/forums/viewtopic.php?f=28&t=63250

 

[Jazzman56]

Thanks Guys i'll look into how much work it entails
I'm not too keen on chopping up a BB of a new bike... --> TOO GUMTREE XD

Regards,
Jazzman

 

[tungsten2k]

Thanks Guys i'll look into how much work it entails
I'm not too keen on chopping up a BB of a new bike...

I seriously don't get all the hoopla… as long as the welds for all the tubes headed into the BB remain intact, since the BBS0x doesn't require or use any threads from the BB, I would just grind that sucker down to 68mm and call it good. It would even give you the opportunity to manipulate where in those 12mm of space you want to place the BBS0x so that you can best align the chainline (as long as you ensure the rest of the unit doesn't have any interference).

Good luck !

-=dave