New Bafang Crank-Drives

[Rusty123]

Here is a photo of the plug on the new controller from EM3ev (large) beside the existing controller plug (small). Both have 7 pins, which is a good sign.

Suggestions as to how to marry these up?

 

[tomcortijo]

If Bafang is not requesting your old unit back you should really save it for someone who can disassemble it and find out what part(s) or system(s) failed. There are not many motors out there with that many miles on them.

They want me to send it back . They want to test what happened. I hope their new motors last longer. 2 months and 2500 miles was not that long...

 

[tomcortijo]

Question.

Has anybody changed the BBS02 Chainring for a smaller one? I have the motor on a 29er with 8 gears and I feel like i can never use the 8th gear (not enough power) and when i get to 2nd gear (i can't use the first cause the chain pops out) i don't have enough torque for those really steep hills.

Suggestions?

 

[astmacca]

Question.

Has anybody changed the BBS02 Chainring for a smaller one? I have the motor on a 29er with 8 gears and I feel like i can never use the 8th gear (not enough power) and when i get to 2nd gear (i can't use the first cause the chain pops out) i don't have enough torque for those really steep hills.

Suggestions?

What are you using now?? On my 26inch MTB i am using the 46T front ring rather than 48T which works ok. I do however have an adapter and 42T on the way as i find even the 46T a little tall and top gear (8th) not very usable. Lots of people seem to be running smaller chain rings though, depending on their usage.

 

[Tom L]

I'm about to. I purchased a 104BCD chainring adapter and spacer from Samd last week. I'm happy with the performance of my 48T ring (26" wheels and 11/34 cassette) but it is a bit big and occasionally rubs on the chainstay if the frame flexes. Not sure how small I'll go yet, maybe only 46T.

 

[astmacca]

I purchased a 104BCD chainring adapter and spacer from Samd last week.

Same same. Its probably arrived by now but i'm in Coral Bay for a week so no playing with modding the bike till i get home.

I have a 30-11 * speed cassette on the back of mine. "Pre Electric" i had a 42T in the front which i was used to and liked. Possible i may try a 34-11 on the back but i will see how the chain-line works out with Samd's adapter kit first.

Its not so much hills that are the issue for me, its the headwinds. I have my bike with me up here and did a 26km ride today. Half was into 15-18knt headwinds and a 28 degree ambient temp, sunny day, where having the motor was great. Using 40-50% assist by current i was still pushing, but able to maintain 25/28km road speed easily. Half an hour of that and the motor was warm to the touch but no where near what you could call hot.

 

[cycborg]

when i get to 2nd gear (i can't use the first cause the chain pops out) i don't have enough torque for those really steep hills.

Easiest fix for this is adjusting the derailleur limit screw. If this doesn't work, it could be a bent derailleur hanger, worn cogs and/or chain, or the derailleur could need lubrication. Any bike shop should be able to help you with these things, since they don't really have anything to do with the e-assist system.

 

[Shorty]

I have a BBs02 750/48v fitted to a full suspension Kona Dawg with an Alfine rear IGH, the chain line is pretty much at the limit. The Bafang came with a 48t cog which in slow off road stuff is too high, works well on the road though ).
I bought one of those 104 adapters and while it fits ok the chain line is way off and I cannot space it back to get it better aligned due to lack of clearance so it looks like a standard Bafang 46t cog is the limit for my setup.

 

[bgt]

I use this adapter for my 38t chainwheel:
http://www.declic-eco.fr/boutique/accessoires/adaptateur-plateau-bbs01-02-plateau-detail

 

[skyungjae]

Wow, it seems like Bafang really needs to make more cog options.

 

[Samd]

I have a BBs02 750/48v fitted to a full suspension Kona Dawg with an Alfine rear IGH, the chain line is pretty much at the limit. The Bafang came with a 48t cog which in slow off road stuff is too high, works well on the road though ).
I bought one of those 104 adapters and while it fits ok the chain line is way off and I cannot space it back to get it better aligned due to lack of clearance so it looks like a standard Bafang 46t cog is the limit for my setup.

Hi Shorty, can you tell me more about your particular setup so I can take a look at my adapter design?
I'm finding my own setup ok with the extra spacer but if I need to make other shaped spacers I can to bring the ring inboard or outboard...

I'm finding my own drives a lot nicer with a 36T primary drive.

 

[GeoKrpan]

Wow, it seems like Bafang really needs to make more cog options.

Why didn't Bafang drive the crank on the left side? That would have allowed the use of any size chainring on the right side. If they drove it on the left and supplied a right side crankarm with the proper offset, a triple crankset would be possible.

In the meantime, a SRAM Dual Drive rear hub ought to do nicely.

 

[GeoKrpan]

Cog GI
11 108.5
13 91.8
15 79.5
17 70.2
20 59.7
23 51.9
26 45.9
34 35.1

GI = Gear Inches

Above is a chart of gear inches for a 46 tooth chainring and a 11-34 eight speed cassette and 26x2.125 tires.

A seasoned cyclist would look at that and say that the low gear, 35.1, is adequate with 750 watts of assistance.

 

[tungsten2k]

Cog GI
11 108.5
13 91.8
15 79.5
17 70.2
20 59.7
23 51.9
26 45.9
34 35.1

GI = Gear Inches

Above is a chart of gear inches for a 46 tooth chainring and a 11-34 eight speed cassette and 26x2.125 tires.

A seasoned cyclist would look at that and say that the low gear, 35.1, is adequate with 750 watts of assistance.

So bottom line is I should have reqeusted the 46T ring when I ordered - bummer.

On a plus side, IT'S HERE !

On a possibly negative side, I did a test-run to make sure it appeared to work, and the "+" button on the PAS control unit doesn't seem to work: when I power it on, it defaults to PAS setting one. If I press "-" it goes to PAS 0, if I press "+" nothing happens... it won't go back PAS 1. If I power off and power back on, it defaults again to PAS 1, if I then hit "+" it still stays on PAS 1. When I press the thumb throttle when in PAS 1, the motor begins to drive.

So am I stuck with a bad C691 controller (since the switch is tied to the controller) ?

-=dave

 

[tomjasz]

So am I stuck with a bad C691 controller (since the switch is tied to the controller) ?

-=dave

WOW! I'm sad to here that! I had a bad controller to, it was immediately replaced and sent by EM3ev. Mine failed by losing several lines in the display.
Who did you by from?

T

 

[skyungjae]

At least you got yours. I'm still waiting...

2014-10-14 16:19:13 QC OK
2014-09-22 09:04:39 Testing
2014-09-20 10:16:03 Payment accepted

You'd think they'd ship it pretty quickly after passing QC.

 

[tomjasz]

Would you share what your final costs are for the BBS02 and battery pack? Not to point a finger and be critical but to share just what is saved by waiting patiently. I paid EM3ev which worked out well, but it was a premium. I then tried lectric cycles and paid even more of a premium for not a whole lot better support. Actually slower. Knowing what I do today I'd be willing to take more of a risk if the actual price difference was significant.

If you wouldn't mind, it would help myself and others.

Thanks,

T

 

[GeoKrpan]

Cog GI
11 113.2
13 95.8
15 83.0
17 73.2
20 62.3
23 54.1
26 47.9
34 36.6

Here is a chart for a 48 tooth chainring, everything else the same.

There is only a 1.5" difference on the low end. 1.5" is not a material difference, you wouldn't notice it.

On the other hand you would probably notice the diference on the top end, 4.7", but still, it wouldn't be a dramatic difference.

Cog GI
11 108.5
13 91.8
15 79.5
17 70.2
20 59.7
23 51.9
26 45.9
34 35.1

GI = Gear Inches

Above is a chart of gear inches for a 46 tooth chainring and a 11-34 eight speed cassette and 26x2.125 tires.

A seasoned cyclist would look at that and say that the low gear, 35.1, is adequate with 750 watts of assistance.

So bottom line is I should have reqeusted the 46T ring when I ordered - bummer.

On a plus side, IT'S HERE !

On a possibly negative side, I did a test-run to make sure it appeared to work, and the "+" button on the PAS control unit doesn't seem to work: when I power it on, it defaults to PAS setting one. If I press "-" it goes to PAS 0, if I press "+" nothing happens... it won't go back PAS 1. If I power off and power back on, it defaults again to PAS 1, if I then hit "+" it still stays on PAS 1. When I press the thumb throttle when in PAS 1, the motor begins to drive.

So am I stuck with a bad C691 controller (since the switch is tied to the controller) ?

-=dave

 

[tungsten2k]

So am I stuck with a bad C691 controller (since the switch is tied to the controller) ?

-=dave

WOW! I'm sad to here that! I had a bad controller to, it was immediately replaced and sent by EM3ev. Mine failed by losing several lines in the display.
Who did you by from?

T

I'm not ready to blame the vendor yet, since every vendor can deliver faulty product and I haven't even tried to contact them about it. I was running it off 2x 3A 6S 30C packs in series (from my 500-class heli) just to check it out. I didn't get much time so will investigate more tonight. The packs were at storage voltage (3.85/cell) and only 12 of them (vs the std 13S), so maybe the voltage is too low for first boot up/initialization ? I need to search this thread for the software and wiring to connect to it and find out what its settings are.

I'll try and verify everything tonight.

As for costs:

• $534.52 - BBS02/48/750/25 shipped to San Francisco
• $161.72 - 6x 5A 4S 20C Lipo packs shipped to same
• $696.24 - Total

I expect to spend another $50-$100 in wiring and battery securement, depending on which way I go.

I already have an iCharger 308Duo for charging at home, and have already tested a very lightweight 72W charge option for the road (charging at 4S6P):

http://www.amazon.com/IBM-08K8213-FRU-72-Watt/dp/B000E3G7CI

or a similar 120W option:

http://www.ebay.com/itm/like/321395850420?lpid=82

This is for now, until I research a more permanent and convenient 12S charging solution.

-=dave

 

[tungsten2k]

Update: I charged all 6 4S1P 5Ahr 20C packs and connected them in a 12S2P 10Ahr 40C configuration and connected to the BBS02/750W/25A. There must be one helluva filter cap in there because the connection spark was crazy powerful

This time I got 5 levels of assist and button is working. I wiggled the wires all around to try and trigger a possible intermittent connection some where and couldn't get the "+" button on the PAS to fail again, so I guess we'll chalk it up to Gremlins

I ordered the unit from Green Bike Kit for those who were interested. Shipping via "FedEx International Economy" was just over $100 to San Francisco. I ordered 10/13 along with various ancillary items such as a BB tool, some different handlebar switches (which apparently don't come with connectors for the Bafang) and some hall-effect sensors that I had planned to use with the Hope hydraulic brakes, but now I'm not sure how they could possibly work - need to research more. The package arrived 7 days later on 10/20.

I ordered the batteries, along with some 2->1 HXT power and 4S JST balance parallel adapters from Hobbyking US warehouse on the same day 10/13 and they arrived 4 days later on 10/17.

I bought an older 2001 KHS bike with many great upgrades including Hope hydraulics, awesome Mavic hubs and tubeless doublewalls, LP Composites B5 carbon fiber bars, Giant carbon fiber seat post (which unfortunately was nearly cut in half for the previous short rider, so I'll have to replace ), Thomson Elite stem, FSA ACB headset, Wellgo LU-313 pedals, and Cannondale IQ108 Speedo/Odometer. The guy was really short for this large frame and the fact that this 2001 bike looked nearly unused, leads me to believe the guy was more of an equipment guy rather than a rider.

I was going to go with a new cheaper Specialized or Diamondback sport hybrid but at around 33lbs for a large frame, saving 3+lbs and getting full suspension/better components seemed like a better move. Unfortunately the hardpack lipos are *just* large enough to not quite fit perfectly in this small frame so I may have to remove them from the plastic hardpack cases. I'll update once I have it rolling.

Thanks again for all the personal help from members and wealth of information in this forum. I would never have embarked on this project without it !

-=dave

 

[tomjasz]

Nice ride! The KHS is a nice frame.

 

[jpo]

Bafang make a 42 tooth chain ring.
Does anyone one where to find one?

 

[joshseitz]

Bafang make a 42 tooth chain ring.
Does anyone one where to find one?

This one: http://www.alcedoitalia.it/shop/accessori-bbs/corona-42-denti-per-bafang-centrale-bbs01/

Mine just broke a tooth after only around 300km. Contacted the manufacturer in Italy regarding warranty. Crossing fingers, as it is an expensive chainring. Otherwise works well, as it offers a better chainline in most circumstances than the stock ring. And honestly I can't imagine needing taller gearing with this kit. 42/11 will get you over 30 with moderate pedaling.

 

[Samd]

Bafang make a 42 tooth chain ring.
Does anyone one where to find one?

I make 104 bcd spider adapters, in the for sale section or on fleabay...

 

[skyungjae]

Would you share what your final costs are for the BBS02 and battery pack? Not to point a finger and be critical but to share just what is saved by waiting patiently. I paid EM3ev which worked out well, but it was a premium. I then tried lectric cycles and paid even more of a premium for not a whole lot better support. Actually slower. Knowing what I do today I'd be willing to take more of a risk if the actual price difference was significant.

If you wouldn't mind, it would help myself and others.

Thanks,

T

48V 750W BBS02 Bafang Central Motor - LCD : C961 1 $420.00
48V11.6Ah Bottle-09 Panasonic Battery & Charger - Color : Black 1 $308.00

Total products : $728.00
Total shipping : $150.09 (to California)
Total: $878.09

Considering that I placed my order over a month ago and there are still no signs of them shipping. I feel it would've been faster (and cheaper if you equate time with money) to have paid more to a different vendor.

People I know who've ordered from them in the past had always gotten their parts relatively quickly. I thought it was the week long holiday at first, but that was a while back.