New Bafang Crank-Drives

[hoka]

Here is my 750 watts build:



A Bafang technician is going to come to re-program the motor for Throttle use and I am trying to find out what possibilities there are so I can have him do it exactly the way I want it. Does anyone know what the programming possibilities are?

 

[Rober]

USING MY OWN CRANK ARMS?
I'm wanting to build a low-speed 24" wheel, hill-climber capable of 15 mph top speed, able to climb 10% grade at any speed, total weight of bike and me = 100kg. My limitation is the crank length; due to a hip impingement I use a 115mm to 125mm crankset (some BMX cranks are that short). Second limitation is that I want to use my existing 36V, 3C, 10Ahr battery. I was getting ready to get a MAC 12-T laced into a 24" rear wheel when I learned about the Bafang mid-drive. I have complete confidence I can make a hub motor work but there are some open questions about the mid-drive regarding chainline and replacing crank arms. Here are my questions:
I always seem to messing with the location of the front chain ring to minimize bend in the chain; is anyone finding the chainline to be an issue?
It looks like the Bafang has a standard square taper spindle for the crankarms; do you see any problem with me either cutting off the spider of my short crank set, or using two short left crankarms (of course I would need two left pedals to go with it)?
Robert

 

[usf_tim]

I was thinking of using one of EM3ev battery packs with the Bafang 750W motor.

http://em3ev.com/store/index.php?route=product/product&path=35&product_id=161

Has anyone tried this battery with 750W motor? Will this pack be able to handle the current? Does anyone know what em3ev charges for shipping to US?

Not sure if i want to get the motor from aliexpress or from lectriccycles. Looks like its about 40% more from lectriccycles but they are in US and can do some firmware changes on the controller. They also have free shipping on their batteries so not sure what is the best deal all around.

http://www.aliexpress.com/item/48v-750w-8fun-bafang-bafun-BBS02-Electric-bicycle-motor-crank-shaft-motor-conversion-kits/1326047038.html

http://lectriccycles.com/products/750-watt-mid-drive-conversion-kit

BTY i found this youtube video on how to install the kit..Seems to be alot of questions about motor install.

https://www.youtube.com/watch?v=jf6BMf28ats

Thanks

Tim

 

[teslanv]

Here is my 750 watts build:



A Bafang technician is going to come to re-program the motor for Throttle use and I am trying to find out what possibilities there are so I can have him do it exactly the way I want it. Does anyone know what the programming possibilities are?

@hoka,

That is a nice looking ride there.

Factory only Programming options (Special Software required) include:

LVC - for 12S LiPo, I'd recommend 42V-44V, or about 3.5V/cell

Max Speed: 31 MPH (50kph) or unlimited

Throttle Response Adjustments and/or throttle only

Other Advanced Programming, which can be user-adjusted include, by following the instructions in the manual:

PAS Settings (from 2 to 9 levels) - I find the most useful is to set to 9 levels
Wheel Diameter (20", 24", 26" & 700cm)
Backlight Brightness

 

[teslanv]

Not sure if i want to get the motor from aliexpress or from lectriccycles. Looks like its about 40% more from lectriccycles but they are in US and can do some firmware changes on the controller. They also have free shipping on their batteries so not sure what is the best deal all around.

Thanks

Tim

I bought mine from lectriccycles.com and have no regrets. Fast shipping (however now they have a three-week backlog), excellent customer service, custom programming, free shipping.

For batteries, check out my build for how to do a custom 12S 10AH HK LiPo Pack. For that I spent $165. That is where I saved my money...

 

[Rollodo]

http://em3ev.com/store/index.php?route=product/product&path=35&product_id=161

Has anyone tried this battery with 750W motor? Will this pack be able to handle the current? Does anyone know what em3ev charges for shipping to US?

Not sure if i want to get the motor from aliexpress or from lectriccycles. Looks like its about 40% more from lectriccycles but they are in US and can do some firmware changes on the controller. They also have free shipping on their batteries so not sure what is the best deal all around.

http://www.aliexpress.com/item/48v-750w-8fun-bafang-bafun-BBS02-Electric-bicycle-motor-crank-shaft-motor-conversion-kits/1326047038.html

http://lectriccycles.com/products/750-watt-mid-drive-conversion-kit

It says that the pack's discharge current is recommended as 20A continuous, the motor controller draws 25A max. Do you see yourself pushing the motor to its limits at all times? I guess it all depends on the gearing you use, but that the beauty of mid drives, as the user isn't limited to the gearing, as is the case with hubs.

Simply put, Lectric Cycles is a US based vendor. I'm in the US, therefore, I'll consider getting this kit for 3 reasons - support local economy (however relevant it might be, given that the kit itself is made overseas), warranty, and shipping time.

I bought mine from lectriccycles.com and have no regrets. Fast shipping (however now they have a three-week backlog), excellent customer service, custom programming, free shipping.

This. Backlog talks to the kit's popularity.

 

[-dg]

Does the installation use the bottom bracket threads, or does it thread one side of itself into the other, floating in the BB and clamping itself to the faces?

The latter is basically the case -- the axle assemble is inserted into the BB shell, with a threaded retaining ring (and a locking ring, depending on BB width) compressing the unit against the BB faces. The internal threads on the BB shell do not come into play.

Maybe more concerning: there was some evidence that the torque of motor had in fact been rotating the entire assembly slightly within the BB shell. I expected to find a single, sharp, V-shaped indentation in the steel of BB shell from each of the mounting plate ‘protrusions’. In fact, I found that each of the indentations was a bit wider than expected. Instead of a perfect V shape… each indentation was shaped more like \_/ That is, each of the indentations was slightly wider than expected.

Retaining ring and locking ring were torqued down tight when originally installed, the BBS02 was not movable by hand force, and the retaining ring and locking ring showed no signs of having loosened since the original installation. My best guess is that the power of the motor was resulting in very slight rotation of the entire assembly within the BB shell over time... eg, the mounting bracket 'protrusions' weren't sufficient keep it perfectly static, and the steel of BB was deforming slightly over time. If so, that is kind of worrisome.

Seems like there are several reports of lock-rings loosening and other indications that the drive might be moving around in the shell. I'm starting to suspect that this mounting system is not up to the job. Bottom brackets take a lot of force from the rider both pedaling and from standing on the pedals over bumps. It seems like a lot to ask from a pair of lockrings to hold all that in place with no motion. Perhaps the drive needs to be bonded or molded into the shell somehow for a more secure fit.

 

[teslanv]

Not sure I'd want to bond the unit's BB into the Shell. Perhaps, as others have suggested, just some lock-tight on the threads and strap it to the down tube.

I think what's critical is you use the proper tool to tighten the lock-nuts down in the first place. I have to wonder if those with loose nuts had used the correct spanner wrench when tightening, or something else like a pipe wrench or ???

I have not had this issue with mine yet. (100 Miles and counting)

 

[Rollodo]

I have to wonder if those with loose nuts had used the correct spanner wrench when tightening, or something else like a pipe wrench or ???

Good ol' hammer works wonders.

 

[speedmd]

Would have been perfect if the used the standard external bb cup setup on the m33 nut or made it a standard hex nut. Lots of tool choices available and some that adapt to a standard torque wrench. Standard spanner will not fit and rotate between my setups motor and swing arm pivot without angling it outward and dinging up the notch. Hammer and pin driver works well.

 

[Kepler]

That's a relief to hear Kepler. Is your BB Steel or Ally?

Just Ally.

 

[coachstevo]

The lock nuts are the old style BB nuts. I think the very early Shimano cartridge BBs used the same. Luckily i had one still sitting around (though it was buried in some old parts box deep in the garage).
Dead easy to tighten properly with the right tool. As others have said careful use of a flat head screw driver and a hammer works too
I haven't had any problems with the locknut loosening, but my commute is just pavement + a tiny bit of gravel road/trail so not a ton of jostling.

 

[spinningmagnets]

A temporary fix for securing the motor against occasional movement (swinging downward because of a hard landing from a jump) might be to use two large hose-clamps. One around the downtube, and then another slipped under the first one,...and then wrapped around the motor shell. This might be a temporary fix that would perform adequately until a more professional design can be produced (Lcrewse?)...

 

[Geebee]

I supose 1 thing to keep in mind is that the system was designed for 250w and then modified to 750w due to demand and most likely never tested for trials riding for some reason

 

[footloose]

... the system was designed for 250w and then modified to 750w due to demand and most likely never tested for trials riding for some reason

Spot on.
I think the overall system is terrific.
But at higher power levels, we are exploring its limits.
My setup actually involved about 1450 watts.
No surprise then, given I was pushing it at 580% of original design specs, that there was some small indication of a possible developing failure.
Not an actual failure, mind you, just an indication that the mounting system might be stressed when pushed well beyond original design specs.

 

[rodgah]

power level doesnt have much to do with the movement if it has a stopper that pushes against downtube. It is all due to the weight of the drive forcing it down over rough ground/jumps. Heavy duty zip ties sound like a good idea

 

[Kepler]

Was feeling a bit lazy today and comuted with the bike at 35kph to 40kph using the throttle button on level 5 to 7 out of nine. The day was warm at around 30 degC and the trip a leisurely 15km

Got home and checked the motor temp. Motor was hot to the touch to a point you wanted to take your hand off the case. Measured with an IR temp gun and it was 55 degC. Although this is not a temp that will burn the motor out, my experience with hub motors is that a case temp 60 degC is getting close to damaging levels.

If you plan to run the 750 Watt BBS02 at its maximum level, I strongly advise you keep it to short bursts.

IMO, this drive is not a good choice for the person looking for a high performance and sustained speed above 40kph. However, use the PAS predominantly and throttle in bursts and you will be rewarded with an excellent riding experience.

 

[Melbourne]

Was feeling a bit lazy today and comuted with the bike at 35kph to 40kph using the throttle button on level 5 to 7 out of nine. The day was warm at around 30 degC and the trip a leisurely 15km

Got home and checked the motor temp. Motor was hot to the touch to a point you wanted to take your hand off the case. Measured with an IR temp gun and it was 55 degC. Although this is not a temp that will burn the motor out, my experience with hub motors is that a case temp 60 degC is getting close to damaging levels.

If you plan to run the 750 Watt BBS02 at its maximum level, I strongly advise you keep it to short bursts.

IMO, this drive is not a good choice for the person looking for a high performance and sustained speed above 40kph. However, use the PAS predominantly and throttle in bursts and you will be rewarded with an excellent riding experience.

hi kepler

This include 350w36v? I ran max level (throttled)on the 40degC days when it was tooo hot and lazy to cycle? didnt have equip to check, but yep very hot to touch.

 

[teslanv]

Was feeling a bit lazy today and comuted with the bike at 35kph to 40kph using the throttle button on level 5 to 7 out of nine. The day was warm at around 30 degC and the trip a leisurely 15km

Got home and checked the motor temp. Motor was hot to the touch to a point you wanted to take your hand off the case. Measured with an IR temp gun and it was 55 degC. Although this is not a temp that will burn the motor out, my experience with hub motors is that a case temp 60 degC is getting close to damaging levels.

If you plan to run the 750 Watt BBS02 at its maximum level, I strongly advise you keep it to short bursts.

IMO, this drive is not a good choice for the person looking for a high performance and sustained speed above 40kph. However, use the PAS predominantly and throttle in bursts and you will be rewarded with an excellent riding experience.

Kepler,

What Voltage battery are you running? - What kind of watts were you pushing through it?

 

[Rusty123]

Based on my experience with the BBS01 on my commuter bike, I'm contemplating putting one on my recumbent. Some different issues involved in that application -- primarily gearing. I've started a separate thread for that over here: http://endless-sphere.com/forums/viewtopic.php?f=28&t=56674. Would welcome any comments.

Russ

 

[deepfraught]

If you did not want to grind away enough material in the center rib to clear the motor you could add something like problem solver for low power apps. if you could find a suitable position.

Thanks that could also work. Only drum front and.coaster single speed rear so speed limited lower power is a good idea

 

[Cinelab]

Wondering if the BBS02 would fit on a Mongoose Beast.

BB on the Bbeast is 110mm.

Is there a way to make it fit?

Maybe using one of these above.

 

[teslanv]

Wondering if the BBS02 would fit on a Mongoose Beast.

BB on the Bbeast is 110mm.

Is there a way to make it fit?

Maybe using one of these above.

Max of 72mm on the bottom bracket.

 

[Kepler]

Was feeling a bit lazy today and comuted with the bike at 35kph to 40kph using the throttle button on level 5 to 7 out of nine. The day was warm at around 30 degC and the trip a leisurely 15km

Got home and checked the motor temp. Motor was hot to the touch to a point you wanted to take your hand off the case. Measured with an IR temp gun and it was 55 degC. Although this is not a temp that will burn the motor out, my experience with hub motors is that a case temp 60 degC is getting close to damaging levels.

If you plan to run the 750 Watt BBS02 at its maximum level, I strongly advise you keep it to short bursts.

IMO, this drive is not a good choice for the person looking for a high performance and sustained speed above 40kph. However, use the PAS predominantly and throttle in bursts and you will be rewarded with an excellent riding experience.

hi kepler

This include 350w36v? I ran max level (throttled)on the 40degC days when it was tooo hot and lazy to cycle? didnt have equip to check, but yep very hot to touch.

Probably less risk with the 36V 350W version due to lower available power levels. Rule of thumb: if you need to remove your hand from the motor after 5 seconds or less, you are getting into dangerous territory.

 

[Kepler]

Was feeling a bit lazy today and comuted with the bike at 35kph to 40kph using the throttle button on level 5 to 7 out of nine. The day was warm at around 30 degC and the trip a leisurely 15km

Got home and checked the motor temp. Motor was hot to the touch to a point you wanted to take your hand off the case. Measured with an IR temp gun and it was 55 degC. Although this is not a temp that will burn the motor out, my experience with hub motors is that a case temp 60 degC is getting close to damaging levels.

If you plan to run the 750 Watt BBS02 at its maximum level, I strongly advise you keep it to short bursts.

IMO, this drive is not a good choice for the person looking for a high performance and sustained speed above 40kph. However, use the PAS predominantly and throttle in bursts and you will be rewarded with an excellent riding experience.

Kepler,

What Voltage battery are you running? - What kind of watts were you pushing through it?

Running 12S LiPo so 50V hot off the charger and around 45V nominal. Was pushing around 700W continuous during this ride.