New Bafang Crank-Drives

[paulbram]

when I approached a fairly long hill at which point the battery went down very quickly, started flashing, then finally everything just shut off.

Heat shutdown? Were you in an easy gear for the motor to go up the long hill? I'll assume your battery pack's cells are balanced.
Speaking of which, how much difference between individual cells is considered out of balance?

It does seem odd that the charger is showing a full capacity regardless of your usage.

Ok... I think I figured out my problem. I just took a closer look at my charger and it was set to 220 volts!!!

Yeah... once I switched it to 110 now the LED's are red and it's charging nicely!

Rookie mistake. First of many I'm sure!

 

[0utrider]

to 220 volts!!!

Yeah... once I switched it to 110 now the LED's are red and it's charging nicely!

Adding that to my checklist!

 

[stompatompa]

BMSbattery are selling 2 different displays to this motor, C961 or C963 LCD display.
I mailed them and asked more than a weak ago, but no answer.
Anybody know what the differnece are between the two displays?

 

[EyeInHand]

Question on smooth shifting with these drives:

The PAS system shuts the motor off when it detects you've stopped pedaling, but there's a delayed response. Not good when you have to downshift quickly, either for a quick stop or to maintain momentum in the transition to uphill.

But the brake levers cut the motor, I assume instantly? I imagine the brake lever is a simple contact switch. Seems like it would be fairly simple to either modify a brake lever or make your own pressure sensitive contact switch and put it on the shifter lever. Pressure applied to the shifter lever cuts the motor at the precise moment you need to shift. Long as you're shifting and pedaling to change gears the motor is idle. Makes it intuitive and does it all in one motion. But is there a sudden jump in torque needed on the pedals when the motor cuts out?

Got a trike with a 700c rear wheel I want to motorize, and trying to decide between a big heavy hub drive or one of these Bafang crank drives. I've seen a few examples of both, and both seem to work within limits. Definite pros and cons to both, so no clear winner yet. Long range, moderate to high speeds, and moderate PAS climbing are the priorities in that order. Seems like I can easily get any two of those with either option, just not all three. (Blue Ridge Parkway is nearby, with long, smooth 6-8% grades. Just did a 20 mile trip last weekend, with 1600 feet of total ascent over the course of 2 hours. Top speed 40mph. All manpowered pedaling.)

Seems direct drive hub motors are less efficient in general except when running at speed, but overall more mature with most of the bugs worked out; while these newer crank drives show a lot of promise but still have some production/engineering kinks to iron out? Have motors from the latest production run started showing up yet?

Thoughts?

 

[teslanv]

I actually just tap my brake when I want to shift.
If you want a solution more refined, see Kepler's posts spread throughout this thread. He details such a shifting system you describe, except using the throttle relay.

 

[teslanv]

14S rocks way more that 12S.
Those of you running 12S LiPo, add a 2S or even a 3S in series to your pack.
Its a kick in the pants.
That is all.

 

[tomjasz]

I actually just tap my brake when I want to shift.
If you want a solution more refined, see Kepler's posts spread throughout this thread. He details such a shifting system you describe, except using the throttle relay.

Works for me as well. It's become so routine as to never notice a glitch, because there are none. I bit of practise and it all smoothes out. 34t up a dike today demonstrated just how powerful these motors are.

 

[neptronix]

I also tap the brakes between shifts. It sucks because there is a lot of delay time on my first gen 6fet controller, so i end up losing a lot of speed if i'm climbing uphill doing that.

How's the pedaling cadence on 14S? really fast? like, too fast?

 

[paulbram]

Oh what a difference a charged battery makes! My first commute into work was an absolute disaster thanks to my very embarrassing charging mistake, but a few hours with a proper charge made all the difference in the world! I scaled some significant hills at over 10% on level 1 assist and the BBS02 didn't even flinch! This thing rocks!

My only concern at this point is my breaks! With all this added weight and all of the fairly high speed downhill runs, I know I'm going to be stressing my breaks significantly. If I had one wish for the next version of this kit, it's to somehow support regenerative breaking using the motor. Not necessarily to keep the battery charged as much as to reduce the stress on my break pads!

One other question. Should I be steering clear of bike trails? Today I only used roads since I wasn't sure if it's kosher to use an ebike on bike trails. I suppose this is state/city specific?

Thanks!
-Paul

 

[EyeInHand]

I actually just tap my brake when I want to shift.
If you want a solution more refined, see Kepler's posts spread throughout this thread. He details such a shifting system you describe, except using the throttle relay.

Yup, I can definitely reach back to my motorcycle days and resurrect the "Left Lever Clutch + Right Twist Downthrottle + Toe Shift Gears up or down". Sounds very similar. Just not sure my wife will master it before she hits a tree, or in this case burns up a motor or pops a chain. :?

I'll look up Kepler's posts. I bet a simple contact switch on the shifter would work nicely. Almost a toggle with three positions:
1. Middle without any finger pressure is ON
2. Pressure forward or back is OFF
3. Spring loaded, so returns to the Middle ON position when pressure is released.

You could even do it with two small spring loaded kill switches on the shifter lever, one on the front for the thumb and one on the back for the index finger. You'd never have to stop pedaling and throw off your cadence.

 

[dumbass]

Oh what a difference a charged battery makes! My first commute into work was an absolute disaster thanks to my very embarrassing charging mistake, but a few hours with a proper charge made all the difference in the world! I scaled some significant hills at over 10% on level 1 assist and the BBS02 didn't even flinch! This thing rocks!

My only concern at this point is my breaks! With all this added weight and all of the fairly high speed downhill runs, I know I'm going to be stressing my breaks significantly. If I had one wish for the next version of this kit, it's to somehow support regenerative breaking using the motor. Not necessarily to keep the battery charged as much as to reduce the stress on my break pads!

One other question. Should I be steering clear of bike trails? Today I only used roads since I wasn't sure if it's kosher to use an ebike on bike trails. I suppose this is state/city specific?

Thanks!
-Paul

I don't think you will ever see regen on this type of setup. Remember it has a freewheeling effect when the motor is off. Therefore, when your braking the motor can't be turned which is needed for regen to work. But still it would be a nice thing to have.

Bob

 

[tahustvedt]

Anyone know how to splice wires in to control a headlight via the BBS display? According to the manual, pressing and holding "+" will activate the backlight and headlight (if installed).

 

[dumbass]

Anyone know how to splice wires in to control a headlight via the BBS display? According to the manual, pressing and holding "+" will activate the backlight and headlight (if installed).

I thought that was only an option (if equipped).

Bob

 

[tahustvedt]

Maybe there's an unused pad on the display PCB that that can be connected to trigger a relay.

 

[Craig F]

Hey Guys....A quick question..
Is the Chain wheel in the Bafang 48V 750W mid drive kit compatible with a 10 speed chain ??
Thanks

 

[Kepler]

Yes it is.

 

[Craig F]

Yes it is.

Thanks mate...I am building a bike specifically for the Bafang mid drive..Good to know I can go ahead and order 10 speed components..
This is the Frameset I am using......http://pro-liteoz.com/store/products/frames/cuneo-gp-frameset-white-edition-.html

Also with a single chainwheel.....and going to run a 10 speed cassette (36-11t), what length rear cage derailleur would I need...
A Medium cage or long cage MTB rear derailleur?....Any ideas..?

 

[--freeride--]

Yes it is.

Thanks mate...I am building a bike specifically for the Bafang mid drive..Good to know I can go ahead and order 10 speed components..
This is the Frameset I am using......http://pro-liteoz.com/store/products/frames/cuneo-gp-frameset-white-edition-.html

Also with a single chainwheel.....and going to run a 10 speed cassette (36-11t), what length rear cage derailleur would I need...
A Medium cage or long cage MTB rear derailleur?....Any ideas..?

I would go for 8 speed, 10 speed is not as strong...

you only need a short cage... i would get a damped one.

P.s.: 8speed sram shifter is compatible with 10speed shimano deraileurs. So you can have damped 8 speed

 

[speedmd]

10 speed works fine and most chains are as strong if not stronger than the 8 speed stuff unless you get something made special for the app. There is also ebike specific chain made now you may want to look at.
http://www.kmcchain.com/en/product.php?act=view&id=20
All road type chain wheels will run it.
Short cage is only good up to a 28 or so tooth cassette. You will need a long cage or one that can run a 36 tooth rear.

 

[Lenk42602]

Short cage is only good up to a 28 or so tooth cassette. You will need a long cage or one that can run a 36 tooth rear.

I believe you are mistaken. Cage length does not determine max cog size.

I have two different 1 x set ups on my pedal bikes with many miles on them.

I have a 1 X10 set up running a wolf tooth components 42t rear max cog on a sram x9 clutched short cage. works fine.

I am running an 11-36 cassette on a 1X9 set up. Short cage 9 speed 5500 series 105 derailleur. Had to replace the b screw with a longer one, other wise no issues.

Been running this set up on a pedal bike prior to the lead sled for 2000 + miles.

 

[speedmd]

Lenk, you can look up the published data from any of the manufactures on specific RD's and what they recommend max cassette cog size is. Unless they are specifically set up to adapt to large rear cassettes, you can not tell folks that short cage will work with a 36 tooth. Just does not work straight across the large spectrum of bike gear in use in my experience.

 

[BigBird]

My understanding is that each electric motor system has some RPM that is optimum for maximum efficiency (range).

Can anyone tell me what that would be in PEDAL RPM for the Barfang drives? And is it different for different Wattage/Voltage models?

Thanks!

 

[Craig F]

Thanks so much to you guys that responded ...Thumbs Up

Freeride.......The reasoning for 10 speed is that maybe sometime in the future I may want to covert back to a standard bike, so 10 speed would suit me better.
From what I have researched there are some strong 10 speed chains available....

Lenk..........Thanks for the link mate...To be less stressful to the short cage My thought was that a Medium cage may be ok .?..As we won't have the double or triple front chain wheel deal going on ,where a larger extension range would be required for the rear derailleur I was also thinking a long cage wouldn't be needed....

Speedmd..........I think you have a valid point ..What's your thoughts on a Medium length cage....

 

[mushymelon]

Its a single up front so as long as your within the chain wrap capacity of your derailleur a short cage works just fine. Chain will be tighter too.

The "capacity" of a particular derailer model is the largest range of sprocket sizes it can handle:

36t - 11t = 25t chain wrap capacity and up and your good.

Manufacturers have to assume that their customers are clueless, and will expect the chain to have some tension on it even in the bad gears where the chain is using small chainrings with small rear sprockets. Thus, the rated chain-wrap capacity is very conservative. A competent cyclist who uses the gears properly can generally exceed this by several teeth with no problem.
Most derailleurs also specify a maximum size rear sprocket. This is often a pessimistic value, based on the largest sprocket that is normally provided as part of that group.

 

[neptronix]

10 speed chain is weaker than 7-8 speed chain, because it is narrower and there is just less metal... if you are running a BBS02, it could wear at a significant rate to be a problem..
You will probably be okay with a BBS01 however.