New Bafang Crank-Drives

[0utrider]

Considering that I placed my order over a month ago and there are still no signs of them shipping.

Crikey!

 

[tomjasz]

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...

I imagine shipping to the USA is crazy high, but your spider seems to be one of the better price points.
Link?

 

[NFN01]

Hi All

New Member here. But Have been following this thread and the Programming thread.

I have just put a BBS02 750W on my KMX Venom recumbent trike. Power source is 48V 15Ah LiFePo4 with BMS split across the rear panniers.

Not fully installed yet. But have done 20 miles worth of testing and the battery indicator is still showing full. Had 30mph on 38T to 11T gear selection.

I have also got dual front chain ring setup. 48T-38T on a spider adapter with a 3mm spacer ring between the spider and motor output hub.
I have also got round the front derailleur not being able to reach the outer chain ring. When the bafang motor is fitted the BB
effectively becomes a 100mm BB with the final output gear housing being in the same position as the small chainring position on a triple setup.
So started looking at the fatbike market for a solution, and found a UK based company that makes a seatube bracket that
allows the fitment of the shimano high direct mount series of front derailleur mechs. The bracket moves the mech out further
to compensate for the wider BB on a fatbike. My problem solved.

This solution make not work on a normal DF bike. My chainline is not an issue so this works.

Got a programming cable so will start experimenting once the installation is fully complete.

In the new year plan to upgrade the rear transmission to a Nuvinci N360 with Harmony.

 

[MargoC]

I've already showed here pictures of Liberator Chilly:

In this week we should finish next Liberator, called Insane:

Both bikes have Bafang 350W 36V BBS motor and 20 Ah LiFePo4 battery. About biggest differences you can read and see more pictures in our blog post:
http://liberatorbike.blogspot.com/2014/10/allow-us-to-introduce-liberator-insane.html

 

[0utrider]

Both bikes have Bafang 350W 36V BBS motor and 20 Ah LiFePo4 battery.

20Amp! Should be able to go to the moon and back!

 

[MargoC]

0utrider
20Amp! Should be able to go to the moon and back!

Yes, with couple of charging, it should

Actually we haven’t tested range of this combo yet. If weather allows, then it would be interesting to find that out within this year. As Liberator is heavier than normal bike – Chilly is more than 30 kg, maybe even close to 40, then it spends more energy too.

We tested range of this Liberator Little Blue in summer:

This bike has 750W 48V BBS motor and 30 Ah LiFePo4 battery. With one charge we managed to ride ca 145 km:

We didn’t do ecodriving, instead, average speed was 25 km/h and some sections even 40 km/h. Approximately 20 km was purely on electric power, with speed of 25-35 km/h. With ecodriving there is possibility to achieve 180-200 km range.

Off-topic, as this bike doesn’t have BBS, Liberator Jäägermeister will have even bigger battery – more than 40 Ah (don’t remember exact amount). When it’s finished we’ll see, what range it will have.

 

[0utrider]

Off-topic, as this bike doesn’t have BBS, Liberator Jäägermeister will have even bigger battery – more than 40 Ah (don’t remember exact amount). When it’s finished we’ll see, what range it will have.

That is still a beautiful bike. Wow. I like the design which has the appearance of being built for the purpose with the focus on an electromotive drive.

 

[tungsten2k]

Has anyone done an efficiency test between running a 750W at 36v vs. 48v ? Is the brushless controller any more efficient running on 48V vs 36V, given everything else being identical ? Or is it the other way around and 36V is more efficient for the controller ?

I did some testing and with my 43 lb bike (30lb bike, BBS02, and 3x HK 4S1P 20C LiPo hardbacks), the 12S setup seems to have far more power than I typically need and I find myself on PAS2 almost exclusively. Obviously it's nice to have it power up the hills, but on PAS2 ( the very bad stock 5-level programming that came on the GBK and I have not built a prgramming cable yet) it won't climb the hills in the lowest gear at PAS2 and I can't really assist due to gearing, so I bump it up to PAS5 and it climbs faster than I can really assist (again, still due to gearing).

My gearing:
Stock 48T BBS02 front chain ring (stock on the bike was 42T)
11-32T SRAM 9-speed cassette
26" tires

At top speed it will do over 30MPH but I'm fine with a top speed closer to 20MPH, so I think I would like to drop the front CR down to 42 or something using one of the many CR adapters. This will also allow me to assist more on the hills, or allow a lower-voltage battery to comfortably pull the hill, but at a slower rate. I can yank the cells out of my HK hardpacks and craft a 36V 10A battery that will weight 0.25% more than my 48V 5A battery, but wondered will I gain more than 25% range due to improved efficency running at 36V, or will I eat up my 25% extra capacity due to 36V running overall less efficiently ? The Frame doesn't have the space to hold all 6 packs for a 10A 48V setup (and I don't think I need the 444Whr for my needs, so would prefer less weight):



If the answer is "nobody knows" it seems something that woud be interesting to find out.

-=dave

ps- I know a lot of my woes surely can be improved upon with proper PAS levels, but I still don't see a way around the gearing.

 

[skyungjae]

According to BMS Battery, they shipped my order on 10/16. They don't have a tracking number though, and the status of my order still says "QC OK." (-_-!)

 

[0utrider]

I bought an older 2001 KHS bike with many great upgrades

Awesome bike with some sweet upgrades. The FS suspension pivot design looks like it will give you no problems with fitting the Bafang to the bottom bracket. Since there was a flange connecting both the bottom bracket and suspension pivot on my bike, I had to use home-made machine bushing to keep the BBS-2 secure and perfectly parallel with the bike frame. Without the bushing on the XR-Pro there was enough play in the bottom bracket to cause it to toe-in a couple of degrees when properly tightened preventing the ring from being squared up with the chain-line. I would have liked to have found a good bike such as yours!

 

[tln]

Has anyone done an efficiency test between running a 750W at 36v vs. 48v ? Is the brushless controller any more efficient running on 48V vs 36V, given everything else being identical ? Or is it the other way around and 36V is more efficient for the controller ?

Running at 36V requires a whole new kit I believe, BBS01 = 36v BBS02 = 48v

I have not built a prgramming cable yet

I have some display cables coming from em2ev, I bought a few to amortize shipping. Let me know if you want one

At top speed it will do over 30MPH but I'm fine with a top speed closer to 20MPH, so I think I would like to drop the front CR down to 42 or something using one of the many CR adapters.

I've got a 42, and can confirm dropping the gearing is totally worth it. I've also got a spare 104 chainring adaptor, that I probably will never use because it moves my chainline too far out.

The Frame doesn't have the space to hold all 6 packs for a 10A 48V setup (and I don't think I need the 444Whr for my needs, so would prefer less weight)

I'm surprised you only need ~200Whr. You could probably fit the packs under the downtube without impacting your front travel.

 

[jkbrigman]

Hi tungsten2k!

(UPDATE: tln is correct, the BBS01 is 36v and the BBS02 is 48-52v. I did not concern myself with answering that question, since it is easy to understand if you only browse http://www.em3ev.com. Your other questions interest me more.)

Your question is similar to a question I've been thinking on now for a couple years. I run 18S (72v "nominal") becuase I started out with a 9c 2810 and you couldn't reach even 20mph with the 2810 unless you go 72v. I do not yet have a "complete conclusion", but I do have two things I can say:

1) When I see voltage decrease on my battery down into the 65-66v range, (near discharge) it takes MORE WATTS for me to maintain a given speed than it does when voltage is higher. That is:

Full charge (72v): cruise 23-25mph, 280 watts
Low charge (66v): cruise 23 mph, 450 watts

So, my initial conclusion is that higher voltage loses less power to heat and lower voltage loses more power to heat. Note that I don't use the word "efficiency": the motor efficiency is a feature of the motor, not of the applied voltage. For me, it is only a question of correct power utilization.

2) In discussions with fellow engineers, one I trust has indicated that controllers can be characterized as "Voltage to current transformers" and that higher voltage applied at the input of the controller does not necessarily mean higher efficiency. I do not yet know the answer to this question, I will have to call on my Linear Systems training later to try to answer the question from this perspective.

3) However: if you have a lower voltage but more batteries in PARALLEL, you can CHARGE FASTER. This is because what limits charging speed is how much current you can put into a battery. If you parallel, you can put much higher current into the total battery than you can into each brick.

4) The controllers/motors we use are complicated little buggers, and understanding how they truly work is a reasonable challenge. I use the simulator on ebikes.ca and it gets me somewhere - I recommend same for you.

I am working on my first 50 volt bicycle. I intend to build a 48v/20Ah battery and I will see what kind of range I get with that. True, it is not an "apples to apples" comparison - I'll be using a different bicycle and different motor drive so that changes everything, but overall range is what I'm trying to understand, then I'll worry about efficiency when I can take detailed measurements of Wh/mile AND motor temperature...

Has anyone done an efficiency test between running a 750W at 36v vs. 48v ? Is the brushless controller any more efficient running on 48V vs 36V, given everything else being identical ? Or is it the other way around and 36V is more efficient for the controller ?

I did some testing and with my 43 lb bike (30lb bike, BBS02, and 3x HK 4S1P 20C LiPo hardbacks), the 12S setup seems to have far more power than I typically need and I find myself on PAS2 almost exclusively. Obviously it's nice to have it power up the hills, but on PAS2 ( the very bad stock 5-level programming that came on the GBK and I have not built a prgramming cable yet) it won't climb the hills in the lowest gear at PAS2 and I can't really assist due to gearing, so I bump it up to PAS5 and it climbs faster than I can really assist (again, still due to gearing).

My gearing:
Stock 48T BBS02 front chain ring (stock on the bike was 42T)
11-32T SRAM 9-speed cassette
26" tires

At top speed it will do over 30MPH but I'm fine with a top speed closer to 20MPH, so I think I would like to drop the front CR down to 42 or something using one of the many CR adapters. This will also allow me to assist more on the hills, or allow a lower-voltage battery to comfortably pull the hill, but at a slower rate. I can yank the cells out of my HK hardpacks and craft a 36V 10A battery that will weight 0.25% more than my 48V 5A battery, but wondered will I gain more than 25% range due to improved efficency running at 36V, or will I eat up my 25% extra capacity due to 36V running overall less efficiently ? The Frame doesn't have the space to hold all 6 packs for a 10A 48V setup (and I don't think I need the 444Whr for my needs, so would prefer less weight):



If the answer is "nobody knows" it seems something that woud be interesting to find out.

-=dave

ps- I know a lot of my woes surely can be improved upon with proper PAS levels, but I still don't see a way around the gearing.

 

[0utrider]

Running at 36V requires a whole new kit I believe, BBS01 = 36v BBS02 = 48v

Yup, that's my understaning too.

I have some display cables coming from em2ev, I bought a few to amortize shipping. Let me know if you want one

You have got my attention as well!
PM sent.

 

[cwah]

how often do you have to change the chain?

 

[RayGo]

The BBS02 also comes in a 36v 500w version. I'm told the BBS02 comes with either a 36v or 48v controller and they may be using the same motor, but I'm not sure. See em3ev.com for the 36v 500w version. hi-powercycles.com even has a 37v 750w setup.

I'm having trouble choosing between the 36v and 48v versions. I currently have a 36v lifep04 20AH battery and looking for more range. So your question about greater range between the 36v and 48v systems with the same battery capacity is of great interest to me. So if you are interested in more range and not greater speed, which battery would provide more range?

Finally, does anyone know when the torque-sensing version of the Bafang BBS mid-drive systems might be available?

 

[Ken Taylor]

Hi tungsten2k!

(UPDATE: tln is correct, the BBS01 is 36v and the BBS02 is 48-52v. I did not concern myself with answering that question, since it is easy to understand if you only browse http://www.em3ev.com. Your other questions interest me more.)

BBS02 can be purchased in 36V or 48V versions but each version can't run at the other voltage.

1) When I see voltage decrease on my battery down into the 65-66v range, (near discharge) it takes MORE WATTS for me to maintain a given speed than it does when voltage is higher. That is:

Full charge (72v): cruise 23-25mph, 280 watts
Low charge (66v): cruise 23 mph, 450 watts

Are you sure your instrumentation is correct? You should see more amps but similar watts.

3) However: if you have a lower voltage but more batteries in PARALLEL, you can CHARGE FASTER. This is because what limits charging speed is how much current you can put into a battery. If you parallel, you can put much higher current into the total battery than you can into each brick.

Not true. There is a maximum charge current per cell. If the cells are all in series then that is the maximum charging current for the battery. If you rearrange those same cells so there are two cells paralleled and each of these pairs are connected in series, you will have halved the battery voltage and doubled the maximum battery charge current which means power is supplied to the battery at the same rate. Charging current per cell will be unchanged as the current is split across two cells and therefore charging time will be unchanged.

Has anyone done an efficiency test between running a 750W at 36v vs. 48v ? Is the brushless controller any more efficient running on 48V vs 36V, given everything else being identical ? Or is it the other way around and 36V is more efficient for the controller ?

I haven't but the difference at maximum efficiency will be small, nill according to a Bafang datasheet.

I can yank the cells out of my HK hardpacks and craft a 36V 10A battery that will weight 0.25% more than my 48V 5A battery, but wondered will I gain more than 25% range due to improved efficency running at 36V, or will I eat up my 25% extra capacity due to 36V running overall less efficiently ?

This is not an option without changing the motor. Expect 25% extra range with 25% extra battery capacity as a first approximation but range mostly depends on the balance between assist and pedaling power.

ps- I know a lot of my woes surely can be improved upon with proper PAS levels, but I still don't see a way around the gearing.

With a mid drive, where you are expecting to pedal, the gearing should match you rather than the motor with the proviso that the lowest gear can be higher because on steep hills you can have higher gearing than you otherwise would as you will be faster with assist. Once the gearing matches you, the motor settings can be changed to provide your desired levels of assist.

With a BBS01 I have to lower my natural cadence when I want maximum power which isn't ideal. With a 48V BBS02 I wouldn't have to which is better but it is a slightly heavier motor.

 

[Ken Taylor]

The BBS02 also comes in a 36v 500w version. I'm told the BBS02 comes with either a 36v or 48v controller and they may be using the same motor, but I'm not sure. See em3ev.com for the 36v 500w version.

BBS02 36v and 48v versions have different motor winds according to this datasheet.

See more at http://endless-sphere.com/forums/viewtopic.php?f=28&t=50104&p=883010#p883010 . As the maximum cadence is too low with the 36V BBS01 I would like a 48V version which exists according to the datasheet but which I haven't seen advertised anywhere. I wonder if you could fit a 48V BBS02 controller to a BBS01?

hi-powercycles.com even has a 37v 750w setup.

The motor power is nominal. Perhaps this is the 36V BBS01 with particular programming settings described differently by hi-powercycles.com for marketing purposes.

I'm having trouble choosing between the 36v and 48v versions. I currently have a 36v lifep04 20AH battery and looking for more range. So your question about greater range between the 36v and 48v systems with the same battery capacity is of great interest to me. So if you are interested in more range and not greater speed, which battery would provide more range?

They will be much the same if you get the same balance between assist and human power. lifep04 is lower energy to weight/volume than some other battery chemistries.

I'm keen to get more range too and minimising assist is the key. I'm currently experimenting with reducing the maximum speed which means no assist in descents or on the flat when pedaling hard. Not the ideal algorithm but good for range.

 

[Samd]

The units really just differ because the BBS02 motor is slightly beefier so it can take a bit more power/heat. In my mind not an issue if you already have a 36v battery and want to commute to choose the 36x500w instead of the 48x500w.

These power levels are nominal anyway and in my experience the units dish out roughly double - but are rated for continuous interpretation of laws, not peak.

 

[Ken Taylor]

The units really just differ because the BBS02 motor is slightly beefier so it can take a bit more power/heat.

You've had some experience with the BBS02 and BBS01. Do you think the BBS02 controller would fit on a BBS01? I note that Em3EV uses the same photo for the BBS01 controller and BBS02 controller.

 

[teslanv]

You've had some experience with the BBS02 and BBS01. Do you think the BBS02 controller would fit on a BBS01? I note that Em3EV uses the same photo for the BBS01 controller and BBS02 controller.

Negative. You cannot swap BBS01 & BBS02 controllers. The BBS01 is for a 36V battery and the BBS02 is for 44V-54V Battery.

 

[Ken Taylor]

You've had some experience with the BBS02 and BBS01. Do you think the BBS02 controller would fit on a BBS01? I note that Em3EV uses the same photo for the BBS01 controller and BBS02 controller.

Negative. You cannot swap BBS01 & BBS02 controllers. The BBS01 is for a 36V battery and the BBS02 is for 44V-54V Battery.

The reason for wanting to swap was so the BBS01 could run on 48V. That would allow the maximum cadence to increase by 25% to about 112 rpm which would match maximum human cadence better without having to go to a heavier BBS02.

Maybe the BBS02 controller doesn't fit though. Does anyone know more?

 

[RayGo]

Okay, now I'm really confused about the differences between the BBS01 and BBS02 mid-drive units. I thought the main difference between the two was that the BBS02 was a bigger motor able to handle more heat and power. I also thought the controllers were basically the same except that one was programmed to run at 36v and the other at 48v. At least that was what I was thinking based on what I read on these forums and at em3ev.com.

I was toying with the idea of getting the 36v 500w BBS02 unit now since I have a 36v battery. Then when the 36v battery died, I could get a 48v battery and reprogram the BBS02 controller to 48v and 750w. So it really boils down to actual physical differences between the 36v and 48v controllers versus just programming changes.

However, I'm still not sure about the range capability of a 36v vs. 48v battery. Let's assume a 36v 10Ah vs. 48v 10Ah battery. The 36v battery gives 360watt-hours vs. the 48v battery giving 480wh. So its 360wh vs. 480wh of energy. Will this translate in the real world of e-biking, all else being the same, to greater range with the 48v battery with 48v motor? Or will the power consumption of the higher voltage motor use up this additional energy and result in just marginal difference in distance over the 36v BBS02 with 36v battery? My analogy is a V6 vs. V8 gas engine. The V8 may have more power and speed, but the V6 will produce the greater mpg. Anybody know the answer to his question or have any experience to share?

Finally, what about the torque-sensing version of the BBS02? I thought I read in one of these threads that Bafang already demonstrated such a system earlier this year. I'm hoping to get this version to eliminate the problems people are having with PAS. I currently have an old ZVO Inc. mid-drive system that only has throttle control and I love it, but it's heavy, takes up the entire central frame area and noisy. Can't wait to put a stealthy BBS02 system on my new road bike.

 

[Ken Taylor]

I was toying with the idea of getting the 36v 500w BBS02 unit now since I have a 36v battery. Then when the 36v battery died, I could get a 48v battery and reprogram the BBS02 controller to 48v and 750w. So it really boils down to actual physical differences between the 36v and 48v controllers versus just programming changes.

The motor wind is different as well.

However, I'm still not sure about the range capability of a 36v vs. 48v battery. Let's assume a 36v 10Ah vs. 48v 10Ah battery. The 36v battery gives 360watt-hours vs. the 48v battery giving 480wh. So its 360wh vs. 480wh of energy. Will this translate in the real world of e-biking, all else being the same, to greater range with the 48v battery with 48v motor?

Yes, because it is physically bigger and heavier with more cells. Range is proportional to watt hours if you keep the same riding style. In general, range is uncorrelated with battery voltage.

Or will the power consumption of the higher voltage motor use up this additional energy and result in just marginal difference in distance over the 36v BBS02 with 36v battery? My analogy is a V6 vs. V8 gas engine. The V8 may have more power and speed, but the V6 will produce the greater mpg. Anybody know the answer to his question or have any experience to share?

The V8 is likely to be operating at a point of lower efficiency but under the right circumstances the V8 could give better mpg. The higher voltage motor is not, in general, less efficient. In the Bafang table above it shows the same maximum efficiency for both motors. If you travel faster with either the V8 or e-bike the range or mpg goes down fast because power used to push through air goes up with speed cubed.

 

[RayGo]

Thanks for the clarification.

Let me try this scenario. Let's say I have a bike with a 48v 500w BBS02 unit powered by a 48v 15Ah battery. I then have an identical bike but with a 36v 500w BBS02 unit and a 36v 20Ah battery. Both batteries put out 720wh. Under the same conditions, how would the ranges of the two bikes compare? Wouldn't they be about the same assuming the total e-bike weight is also about the same?

Finally, does anyone know if the 36v and 48v BBS02 controllers are the same hardware-wise/physically and differ only in their programming? teslanv says the BBS01 and BBS02 controllers cannot be swapped since the BBS01 is for 36v only and the BBS02 is for 48V only. So does that means the latest 36v 500w BBS02 mid-drive unit uses the updated 25a BBS01 controller but with the larger BBS02 motor? That implies the 36v 500w BBS02 motor is the same as the 48v 500/750w BBS02 motor. If they are not the same then that would mean there are 3 different versions of the Bafang motor. If there are only 2 versions of the motor, then it would appear the 36v and 48v controllers can be swapped. Maybe it's late and I need to go to sleep.

 

[tomjasz]

No! Shipping is really cheap as it qualifies for lowest price with Australia Post by air.
I think I have International Post enabled on the new site, but you can find them on Ebay US if not. Pm me if I have frocked it though!
http://ballaratebikes.com/products/bafang-bbs0x-104bcd-chainring-adapter

Sure enough, $10.50. This means I can put a new chainring on and also put the OEM chainguard back on too. The gearing concept still confuses me and I may lose some top speed by join to a smaller chain ring. But going from 14T cassette to 11T should help. I think?