New Bafang Crank-Drives

Don't get too excited by the 48v "750w" version. It wasn't anything like a 750w hub-motor. The 450w GNG will absolutely blitz it. Think more like the 350w GNG at 22 amps 36v.

if you need 9 T sprocket i have it, d8veh!

If they made an ISIS version that could handle some jumps. I'd be all over this.

full-throttle said:

Your GF must feel lucky :lol:

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Yeah, it's a frockfest :lol:

From the old ref manual ~Feb, not sure if they are still calling it ''BDS01''

Looking at that diagram - am I right that the crank doesn't have a freewheel? I.e. if the motor is powered the the pedals HAVE to turn as well?

The 750w version at the show was a one-off (actually 1 of 3) engineering samples and was set to only about 10A continuous/15A peak power. You could see on the LCD while riding it, you couldn't get it to push more than 600-700 watts peak. The latest batch of 48v 350w motors I received are about as powerful, they do 28-30mph on a mountain bike. The 750w in production form is supposed to support 20-25 amps continuous at 48v. Guess we'll have to wait and see.

The crank does have a freewheel as does the chainring, so you can throttle without pedaling. Pretty much like almost any current mid drive system.

Look awesome, I'll wait for 1k watt crank drives then I'll buy one. So I can challenge Optibike.

lcrewse said:

The 750w in production form is supposed to support 20-25 amps continuous at 48v. Guess we'll have to wait and see.

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REEALyy thats 1200 watts plus hot off the charger! Not bad at all for such a nice looking compact unit! I knew they would get there if you have access to a CNC machine and any motor you want, its not that hard to do really... I am surprized they dont have 2000 watt versions yet to be honest...

Do the crank drives fit in standard 68mm BB's? Might run this in a vintage road bike if so!

Yes fits 68mm with a 33.5 constant diameter

Here is the pdf

http://www.bike-emotion.org/BAFANG%20CENTRAL%20MOTOR%20DRIVE%20SYSTEM%20-BDS01-%20Feb%2018%202013.pdf


and a little more information

http://translate.google.co.uk/translate?hl=en&sl=de&u=http://www.bike-emotion.org/Bafang%2520BBS01.htm&prev=/search%3Fq%3Dhttp://www.bike-emotion.org/Bafang%252520BBS01.htm%26hl%3Den%26biw%3D1440%26bih%3D739

both links taken from the pedelecs forum

so... who's going to be the first to put this on a DH bike?

Thank]s for that, english version makes all the difference :x

Well now we can understand how the numbering system works early on.

Countermark serial number on motor casing as following:
BBS01 36V 250W
15A 25km/h
13010001
1. BBS01: motor type(speed sensor)；
BBS02: motor type(speed sensor with coaster brake)；
BBT: motor type (torque sensor)
2. “36V”: rated voltage; 250W: rated power.
3. “15A”: limited current, 25km/h: max speed.
4. “1301”: production date, produced in January of 2013.
5. “0001”: serial number.

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Going to see what happens when I remove the speed magnet :lol:

They will also fit on a 73mm bottom bracket but slightly longer bolts and spacers are necessary. They usually come with a 40 km/h (25mph) max speed limiter that is controlled through the LCD. The last batch I received I ordered without a limiter, much more enjoyable!

lcrewse said:

They will also fit on a 73mm bottom bracket but slightly longer bolts and spacers are necessary. They usually come with a 40 km/h (25mph) max speed limiter that is controlled through the LCD. The last batch I received I ordered without a limiter, much more enjoyable!

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Yeah I noticed it had a SW limit, but was just curious to see what happens when there is no magnet present.
I swear the unit I rode at CC had more than 3 power levels, but I might be confusing it with a king meter display.

The one I have access to is 36V, top speed was yawnish but the power response was still good.
Was able to weave through a factory mid production without dying

The ones they had at CC, had 3 power levels. This is how they all come. I figure without the magnet it will just not display speedo info and of course not have the limiter engage, but haven't tried that yet.

Impromptu unedited overview of the LCD interface.
[youtube]SL174JCpf74[/youtube]

I am ready for that trifecta. It's not the size of the bottlebattery that counts - it's how you ride it.

This thread is missing the mandatory joke about two nuns riding on cobblestones.

@T3sla:

So, if the 350w units are available, where can a person buy a kit from right now? I looked at the link to the AliExpress site but it looks like the lower end (original) one. The LCD display also looks very different compared to the video that you posted on May 26.

Thanks in advance...

Shanman3us

The biggest problem with these kits seems to be the location the motor is mounted , you would have very low ground clearance ? it wouldn't be good for offroad use either

The standard location further up the down tube like GNG or AFT mid drive kits are in the ideal spot for ground clearance.

Also the high power 750w version doesn't seem very powerful ? The GNG 48v 450w run at 60v and even 48v 1200w cyclone kit will have a lot more power then this 750w version ?

What are the gearteeth inside made of ? maybe they are plastic that's why its limited to 750w ?

jk1,

While I've not disassembled the entire unit yet, the secondary cover is hiding metallic alloy outer ring gear and of all things decent lithium grease in there too.

To get the whole thing apart requires a traditional 4 pawl freewheel removal tool but the hole (the through hole) needs to be large enough in diameter to fit over the tapered axle shaft to reach the 4 square pawls. This needs to be used on the non motor side to remove the retaining nut holding the axle in place.

Once that part is removed, a set of allen wrenches will complete the dissassembly.

I've come up with some rated specs at 48.13v and it looks like most efficiency is at 82.6% with 37.1 N.m. or 27.36 ft lbs torque and 10.37 A for 413w output power. The maximum power spec is: 638w @ 48.13 (minus voltage drop), 16.88 A draw, loaded RPM of 88.6 and torque of 68.7 N.m. / 50.60 ft lbs torque.

What surprised me of this design (and no I have yet to install it, taking a ride to the bike shop today to see if they can provide me the spawl wrench or freewheel removal tool to open the bafang BPM drive.

Now depending on headwinds, level of ground, etc - my math shows normal 48t -> 11 final ratio providing up to 22.598 MPH on a 20" bike
In comparison on a 26" bike the theoretical limit would be: 29.3774 mph

So without limiting of speed (actively) this setup seems just mildly enemic as 638w is not enough to get above 25 on a 26" without some real input from the rider.

My thoughts on this are 2 fold - the mount system should be able to shed heat due to it's mounting method I think this motor could be power increased by about 50% minimum safely - my plan stage #1 is to open the drive, plum in a few more wires (out really) so that my new drive has both the Bafang standard DC connection but also 3 Phase Output at minimum 12G and the hall sensor loom.

While I have it open on the bench I will spec the controller internally, still working to get the flashing software / parameter designer from Bafang so I can program the cutouts in this onboard controller but....

If I can increase current by 1/3 maximum and nominal it would produce 638w at 16.88 A and 48.13v by adding a shunt and increase the maximum to perhaps 22.45A as main battery maximum current for a total at 48v of 1082.925 watts and 68.15 ft lbs of torque.

Final step would be to increase the voltage... presuming that I can retain the 82% efficiency rate claimed, going from 48.13 to 55.5 (15S) nominal then we can recalculate top speeds too: 55.5 * 22.45 = 1245.975 watts * .82 = 1021w useable power and the need to dissipate 1245.975 - 1021 = 224 watts of heat power.

In stock configuration at max power output the losses are on the order of 114w, with the upgraded voltage and current the total increases to 224 watts of heat produced.

Then I realized if the controller is built in (it is) then we can eliminate some weight removing it and if we remove it some of the thermal losses will be dissipated externally to an external controller... this is just theory now - anyone with ideas on the proper tool to remove the crank shaft or on suggestions for modifying this unit.

The other benefit to going to 55.5v would be higher top speed: 55.5 * 2.3297 = 106.0247 RPM @ crank (I think) instead of the 88 RPM at crank maximum - this translates on the above 20 and 26" to be respectively: 27 and 35 mph respectively.

Please weigh in on this at your convenience

-Mike

jk1 said:

The biggest problem with these kits seems to be the location the motor is mounted , you would have very low ground clearance ? it wouldn't be good for offroad use either

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Yup, factory can't use them on step through frames which are big in Europe.
So what they have essentially done is wiped out a large proportion of their sales market (cheaper competition (against Bosch) for step through in Europe)
Mind bog-lining bad move.

Also doesn't work on the 20" folding frames I've seen.

So now it's essentially just for MTB frames, pinning it directly against the bosch system.
Considering euro-bike is two months away everyone is moving to create the bosch anti dump menace

I've come up with some rated specs at 48.13v and it looks like most efficiency is at 82.6% with 37.1 N.m. or 27.36 ft lbs torque and 10.37 A for 413w output power. The maximum power spec is: 638w @ 48.13 (minus voltage drop), 16.88 A draw, loaded RPM of 88.6 and torque of 68.7 N.m. / 50.60 ft lbs torque.

Click to expand...

For contrast the Ananda mid drive systems does 100N.m, with only 5A......dat gearing!

So, if the 350w units are available, where can a person buy a kit from right now? I looked at the link to the AliExpress site but it looks like the lower end (original) one. The LCD display also looks very different compared to the video that you posted on May 26.

Click to expand...

Not sure look a few pages back, I think someone on the forum had a few.
Might order one now, still can't rip apart the one I have access to :?

I doubt these original units can handle much power, there is no need to use components that are rated to higher than production power levels as the controller is matched to the unit out of the box (unlike hub motors).
The controller should be easy to mod, considering who made it :lol:

mwkeefer said:

... the Bafang standard DC connection...

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What exactly is the Bafang standard DC connection? Is there a picture somewhere? Thanks!

t3sla said:

For contrast the Ananda mid drive systems does 100N.m, with only 5A......dat gearing!

Click to expand...

I'm not too sure where that figure comes from, but when I rode a bike with the Ananda crank-drive, it wasn't more powerful than the 250w Bafang CD., which means gutless!

mwkeefer said:

jk1,



If I can increase current by 1/3 maximum and nominal it would produce 638w at 16.88 A and 48.13v by adding a shunt and increase the maximum to perhaps 22.45A as main battery maximum current for a total at 48v of 1082.925 watts and 68.15 ft lbs of torque.

Click to expand...

The TMC unit is similar to the Bafang one. It has about the same power(riding experience). I increased the current from rhe standard 15 amps to 24 amps, but it didn't make much difference to performance. It just made the motor get hotter.

-dg said:

mwkeefer said:

... the Bafang standard DC connection...

Click to expand...

What exactly is the Bafang standard DC connection? Is there a picture somewhere? Thanks!

Click to expand...

The long and short of it is simple:
1.) The anemic controller using likely low end FETs (not IRFB4110s) with high RDSon. Changing these out for IRFB4011 or IRFL4115 for Higher Voltages.

2.) So the standard DC connector is just RED (Positive) and BLACK (Ground) - then you connect the power pack, the LCD Screen and the front Loom (Throttle, Brake Cutout, etc)

3.) By opening and allowing wiring (5 Wires, one for each phase and 5v+ and 5v-) + 3 Wires for the Phases Lines High Voltage and Current

4.) Until I open the cpntroller and upgrade the FETS, caps, etc - just, I would presume 15S would be safest and most maximum since the internal caps are likely 63v.

I see that I forgot to upload and link in the images for this post so here they are:

This is the bottom bracket axle - runout is really bad due to the 80t pulley compounded by the center shear pin 12/15mm 12 T Freewheel.

If anyone else has suggestions, or ideas I am always open

Once I'm done my bench testing and some (about 25-50 to verify) and have been catching my work on tape, I;ll show you the proper install method for the Bafang bottom bracket.

It's way too late / early and I am still seeing data sheeelts

Regards,
Mike Keefer
mwkeefer@gmail.com

d8veh said:

t3sla said:

For contrast the Ananda mid drive systems does 100N.m, with only 5A......dat gearing!

Click to expand...

I'm not too sure where that figure comes from, but when I rode a bike with the Ananda crank-drive, it wasn't more powerful than the 250w Bafang CD., which means gutless!

Click to expand...

Ananda yesterday, rep I was with said it can do 100N.m and has much more grunt than the BF.
TBH I recall more grunt from the Ananda (but not a large amount), that was on flat ground.
Ananda does use a torque sensor unlike BF which only has speed, so it would have been spurting a proportional amount unlike BF (hence the larger feel of power)

The 5A figure is from the brochure and I suspect that means it's for the pedelec market, not what the unit is capable of handling.
I'd bet money it can outdo a bosch :wink: but the BF still wins due to 68mm BB mounting :x