New Bafang Crank-Drives

[Rollodo]

Surely you mean to refer to the 'surface area presented by the rider' rather than 'weight of the rider' here? The weight of the rider would only have any bearing on 'resistance' when climbing an incline.

Above about 20km/h it's air resistance in its various forms that is the problem. There's a good explanation here: http://mccraw.co.uk/wind-resistance-cycling-speed/

I've often though that the only real justification for a drive such as the BBS01 is to assist bicycle users to overcome air resistance (particularly when cycling into the wind) sufficiently to avoid turning to the car! In other words, to be able to cycle at around 25km/h consistently and in all conditions.

Actually, I meant the weight itself, though the surface area is, as you pointed out, the primary culprit. Picture Rider A who weights 100 kg with some body fat on him and surface area X. Now picture Rider B who lifts weights, so he has more muscles, covering the same surface area X, but weighting 110 kg, since muscles are more dense than fat. You now have more downward force onto the bicycle, which creates more drag. Is this correct?

EDIT: dense, not sense.

 

[Warren]

Bike and rider mass are the largest influence up to about 20 km/h. After that, unless you are on a very steep hill, the aerodynamic drag predominates. Rolling resistance goes up linearly with speed. Aero drag goes up exponentially. Like with population, and interest, those exponents can get you in trouble.

 

[Rollodo]

Bike and rider mass are the largest influence up to about 20 km/h. After that, unless you are on a very steep hill, the aerodynamic drag predominates. Rolling resistance goes up linearly with speed. Aero drag goes up exponentially. Like with population, and interest, those exponents can get you in trouble.

Thank you, Warren.

 

[tomjasz]

This means, as I understand it, that Lectriccycles models, immediately available, are all old stock. To bad.


News - 18th Apr. 2014

Please note the information on BBS02 schedule from the previous News Flash from 11th Apr, there is no new news on that subject yet, but we are hoping to receive 48V 500W and 36V 350W in the coming week.



News - 11th Apr. 2014

The 750W BBS02 kits are temporarily out of stock. We are arranging some new stock and expect to have the 48V 500W and some other new models by around 24th April. The 48V 750W and 36V 500W BBS02 production has temporarily stopped whilst a new version 25A controller is finalised. If truth be told, the controller on the 25A controller on the 48V 750W kits was a little under specced (for a 25A controller) and in standard form would actually typically pull almost 30A max from the battery. Bafang are now moving to a stronger 9 fet design from a 6 fet design, for the 25A models. This new controller is due in May, and kits are already on Order.

 

[RWP]

See BBS02 + TerraTrike Tandem Pro build here:
http://endless-sphere.com/forums/viewtopic.php?f=28&t=58166&p=882391#p882391

The motor and battery came from http://www.LectricCycles.com and I can't say enough about the EXCELLENT customer service!

 

[samsavvas]

Actually, I meant the weight itself, though the surface area is, as you pointed out, the primary culprit. Picture Rider A who weights 100 kg with some body fat on him and surface area X. Now picture Rider B who lifts weights, so he has more muscles, covering the same surface area X, but weighting 110 kg, since muscles are more sense than fat. You now have more downward force onto the bicycle, which creates more drag. Is this correct?

Mmmm -I think technically you may be correct, but we need to remember that on all of the well lubricated, smooth-tyred and finely tune bicycles that ES members use :wink: rolling resistance will be so low as to not be a significant contributor to 'drag'. This is the great virtue of ball-bearings! So IMHO when discussing weight-related rolling resistance I think we can ignore bike and rider weight most of the time. Hence I suppose my rather one-eyed views on the virtues of steel bicycles (I live in a flat city BTW). In my part of the world it's aero resistance and head-winds that mostly discourage bicycle use.

Savvas

 

[samsavvas]

Aero drag goes up exponentially. Like with population, and interest, those exponents can get you in trouble.

I read that aero drag actually goes up 'polynomially' - not exponentially - but as I have no idea what this means I'll not enter into any argument!

Actually I think it's hairsplitting and just means that the apparent exponential increase in aero-drag is composed of multiple 'aero-related' factors - friction effects, displacement effects and maybe other stuff only engineers and physicists understand.

The key thing, as Warren points out, is that it's above about 18-20km/h that aero-drag becomes significant. For most every-day bicycle use (upright stance, non-aero clothing, unstreamlined bikes etc) it's the need for a bit more speed in the 20-30km/h range that makes the possibility of electrical assist important. I suspect that in city commuting environments, above 30km/h the advantages of increasing speed become less significant, maybe because aero-drag doesn't go away but continues to increase enormously and because for many of us 'oldies' general 'bike management' in traffic or on bike-ways can get a bit too demanding above 30km/h.

Anyway, I guess I'm suggesting that for most commuters it's the potential to assist in maintaining speeds in the 20-30km/h range that makes the BBSxx so appealing. Interesting line of discussion.

Savvas.

 

[shanman3us]

EVLab in NZ makes excellent, lockable and secure, frame-mounted metal battery boxes. Not triangular but made to fit a variety of known battery shapes.

Savvas.

Thanks. I went to the site but only saw a 'bag' sold separately. Maybe my search skills are too limited...

Shanman3us

Here it is: http://endless-sphere.com/forums/viewtopic.php?f=14&t=50128

I suspect that because the cases are a 'batch production' item Kiwi may only list them at the site when he has a bunch to sell.

Savvas.

Nice, thank you for the link. At least I got a chance to see it. It looks like it can hold quite a wide variety of battery setups.

Shanman3us

 

[tomjasz]

See BBS02 + TerraTrike Tandem Pro build here:
http://endless-sphere.com/forums/viewtopic.php?f=28&t=58166&p=882391#p882391

The motor and battery came from http://www.LectricCycles.com and I can't say enough about the EXCELLENT customer service!

excellent news! Enjoy.

 

[nukezero]

See BBS02 + TerraTrike Tandem Pro build here:
http://endless-sphere.com/forums/viewtopic.php?f=28&t=58166&p=882391#p882391

The motor and battery came from http://www.LectricCycles.com and I can't say enough about the EXCELLENT customer service!

excellent news! Enjoy.

tomjasz - how's your trek pure build coming along?? btw, did em3ev not send you the battery mounting rails?

 

[Kepler]

Another BBS02 conversion for the photo gallery.

This one was for a customer who needed an XL frame to suit his size and an upright riding position due to him having a bad back. He already had a bike that he wanted to convert but the frame was not suitable for the Bafang mid drive. Rather than going out and buying a new bike I suggested we just get a new good quality frame and migrate the parts across. Just waiting on the battery to arrive from em3ev.

 

[pjgold]

Very nice, a frame pack going on this one?

 

[tomjasz]

See BBS02 + TerraTrike Tandem Pro build here:
http://endless-sphere.com/forums/viewtopic.php?f=28&t=58166&p=882391#p882391

The motor and battery came from http://www.LectricCycles.com and I can't say enough about the EXCELLENT customer service!

excellent news! Enjoy.

tomjasz - how's your trek pure build coming along?? btw, did em3ev not send you the battery mounting rails?

I have everything in hand but am confused about the mounting rails. I'm looking for some picture of the mounting to end my confusion. This is when having a vendor on a day or two delay is frustrating. Any idea where I might find how the pack mounts?

 

[Kepler]

Very nice, a frame pack going on this one?

Yes, same as your very tidy conversion.

 

[Warren]

samsavvas,

"I suspect that in city commuting environments, above 30km/h the advantages of increasing speed become less significant....and because for many of us 'oldies' general 'bike management' in traffic or on bike-ways can get a bit too demanding above 30km/h."

I watch the e-assist commuting videos, on here, in sheer terror. I think riding a two wheeler, even a motorcycle, in most industrialized cities is suicidal. I ride hundreds of miles many weeks. But this is out in the hinterlands, mostly during the week, when crazed worker rats are already in their treadmills. There are a few places where I would consider commuting by bike. Some of the northern European bike utopias, for example. Japan is another place. I watched in awe some years ago, as a salaryman in a suit, with an umbrella in one hand, and a cellphone in the other, rode through a city intersection without looking up. Getting a drivers licence in Japan is about like getting a pilots license in the US, and hitting a bicyclist will get your license torn up for life.

 

[pexio]

Hi all,
Long time lurker, first time poster. Below are pics of my just-finished Bafang mid-drive conversion for my girlfriend. Thanks to all the members of this forum who've shared their wisdom and experiences! The bike is a 1994 Mt. Shasta Legacy townie scored off craigslist for $40 which was upgraded with a few items from my parts bin. The kit is a 750w BBS02 unit with a 48v 12ah "frog" battery, both from conhismotor.com.

Wow! Riding an ebike is a BLAST!

 

[shanman3us]

Any thoughts and/or advice welcome....

So, I'll mention that I did do a search of this thread and did get a good overview of what I'm asking about but still didn't really get the black and white clarity that I was looking for. So here goes...

I'm under the impression that the 48v 500w bafang BBS02 is the exact same motor, wiring, strength, weight, size etc. as the 48v 750w bafang BBS02. Is this correct? Also, I understand that the only difference between those two is the actual built-in controller with the 750w one having heavier duty FET's and some form of unrestricted programming. Is that true as well?

It seems like the controller is completely sealed in some form of water proofing material /resin therefore making it impossible to replace the FET's with heavier duty ones. If they were able to provide a replacement controller for 750w model and I decided to swap that with the one that comes with the 500w would that make the 500w one exactly the same in all power respects and function of it's higher rated brother?

As it stands I'm under the impression, at least from what I've read, that the 750w version has a slightly higher top speed but only in throttle mode and it could sustain climbing a longer hill in throttle only without overheating as quickly. In PAS mode that both would be essentially the same. Again, do I have this correct.

Here in Canada we have a cap of 500 watts and as long as I could get that version it would be great to know that by changing the controller only that I could have the same power as the 750w while still having the 500w tag on the motor.

Also, I have just seen a big price difference in the LiOn battery packs at conhismotor.com
A 48v 12Ah 'frog' (including matching charger) for $305 and then the 'water bottle' style downtube pack of the exact same voltage and Amp hours for $495. What would cause a $200 price difference for what appears to be the same battery?

Thank you and I apologize if I missed someone already explaining the above and I just couldn't find it.

Regards, Shanman3us

 

[Warren]

shanman3us,

"Also, I have just seen a big price difference in the LiOn battery packs at conhismotor.com
A 48v 12Ah 'frog' (including matching charger) for $305 and then the 'water bottle' style downtube pack of the exact same voltage and Amp hours for $495. What would cause a $200 price difference for what appears to be the same battery?"

Different cells. "Power cells" vs "energy cells." Check the internal resistance, and continuous/maximum discharge rates listed in the specs.

 

[jslabonte]

Hi all,
The kit is a 750w BBS02 unit with a 48v 12ah "frog" battery, both from conhismotor.com.

Pexio,

Since you are the first (that i am aware of) that bought the kit from conhismotor, can you tell me if the kit came speed limited ?
Also how is the throttle configured? Does it give full speed under any circumstances, or is it proportionnaly limited with the assistance level ?

 

[samsavvas]

I'm under the impression that the 48v 500w bafang BBS02 is the exact same motor, wiring, strength, weight, size etc. as the 48v 750w bafang BBS02. Is this correct? Also, I understand that the only difference between those two is the actual built-in controller with the 750w one having heavier duty FET's and some form of unrestricted programming. Is that true as well?

It seems like the controller is completely sealed in some form of water proofing material /resin therefore making it impossible to replace the FET's with heavier duty ones. If they were able to provide a replacement controller for 750w model and I decided to swap that with the one that comes with the 500w would that make the 500w one exactly the same in all power respects and function of it's higher rated brother?

As it stands I'm under the impression, at least from what I've read, that the 750w version has a slightly higher top speed but only in throttle mode and it could sustain climbing a longer hill in throttle only without overheating as quickly. In PAS mode that both would be essentially the same. Again, do I have this correct.

Like you I am dependent on the experiences of others with the 750W version who have posted at ES. However I think you have most of this generally correct although there are probably other small differences between controllers, especially as Bafang appear to currently be rejigging the 750W one and because different vendors seem to list different voltage/power ratings for different models (eg; there seem to be both 36v and 48v '500 watt' versions!) You might want to read through recent posts at the EM3ev news page as Paul has posted some information about spare parts and controller replacement. It's not much info about spares but it seems to be the best available.

Nice bike BTW. I sort of miss the days when companies making good quality steel bikes thought nothing of building a 'ladies' version of their top range frames. Not sure what the one you've built here is like but I recall Shoguns in full DB cromo being made with dropped top tubes etc.

Savvas

 

[Kepler]

Any thoughts and/or advice welcome....

So, I'll mention that I did do a search of this thread and did get a good overview of what I'm asking about but still didn't really get the black and white clarity that I was looking for. So here goes...

I'm under the impression that the 48v 500w bafang BBS02 is the exact same motor, wiring, strength, weight, size etc. as the 48v 750w bafang BBS02. Is this correct? Also, I understand that the only difference between those two is the actual built-in controller with the 750w one having heavier duty FET's and some form of unrestricted programming. Is that true as well?

It seems like the controller is completely sealed in some form of water proofing material /resin therefore making it impossible to replace the FET's with heavier duty ones. If they were able to provide a replacement controller for 750w model and I decided to swap that with the one that comes with the 500w would that make the 500w one exactly the same in all power respects and function of it's higher rated brother?

As it stands I'm under the impression, at least from what I've read, that the 750w version has a slightly higher top speed but only in throttle mode and it could sustain climbing a longer hill in throttle only without overheating as quickly. In PAS mode that both would be essentially the same. Again, do I have this correct.

Here in Canada we have a cap of 500 watts and as long as I could get that version it would be great to know that by changing the controller only that I could have the same power as the 750w while still having the 500w tag on the motor.

Also, I have just seen a big price difference in the LiOn battery packs at conhismotor.com
A 48v 12Ah 'frog' (including matching charger) for $305 and then the 'water bottle' style downtube pack of the exact same voltage and Amp hours for $495. What would cause a $200 price difference for what appears to be the same battery?

Thank you and I apologize if I missed someone already explaining the above and I just couldn't find it.

Regards, Shanman3us

What you are asking, I doubt any of us on this thread truly know.

I personally believe the exact same controller is used across their range and just programed differently to suit the drive configuration. My understanding is that all versions have the same gearing with all the 36V versions having the narrower motor with a higher kv and all the 48V versions having the wider (and heavier) motor with the lower kv.

So if my thoughts are correct, the 750W and 500W versions would be identical except for programming. Again, I don't know this for sure but I am 90% confident

 

[pexio]

Pexio,

Since you are the first (that i am aware of) that bought the kit from conhismotor, can you tell me if the kit came speed limited ?
Also how is the throttle configured? Does it give full speed under any circumstances, or is it proportionnaly limited with the assistance level ?

jslabonte,
I recall that the speed limit was set to 25 kmh which you can raise to 50 kmh (31 mph) with the basic setup. The kit from comhistmotor comes with no instructions so I went through the basic and advanced settings from the attached C961 manual - all pretty straightforward.

I've been riding the bike for only 2 days, but it seems that the throttle doesn't give full power in most of the lower PAS levels which I think was mentioned upthread. The throttle gives a little boost over the PAS though. In level 9, with the throttle wide open, I'm had it up to 26 mph on flat ground - no pedaling.

This is my first ebike experience so I have no basis for comparison, but I'm impressed with both the kit and comhistmotor (ordered 3/31, arrived 4/11, questions promptly answered).

 

[pjgold]

I have everything in hand but am confused about the mounting rails. I'm looking for some picture of the mounting to end my confusion. This is when having a vendor on a day or two delay is frustrating. Any idea where I might find how the pack mounts?

Here is a picture of the frame pack rail it is simply bolted straight to the water bottle mounts through the slot in the best position for your frame.

Hope this helps.

 

[shanman3us]

Different cells. "Power cells" vs "energy cells." Check the internal resistance, and continuous/maximum discharge rates listed in the specs.

Ahh, OK that makes a lot of sense. So for the layman that means the lower cost cells will not last nearly as long (per charge and lifespan) even if they are taken care of and they can't supply the same amount of sustained power when there is a big load on them. Thanks for that.

Shanman3us

 

[shanman3us]

What you are asking, I doubt any of us on this thread truly know.

I personally believe the exact same controller is used across their range and just programed differently to suit the drive configuration. My understanding is that all versions have the same gearing with all the 36V versions having the narrower motor with a higher kv and all the 48V versions having the wider (and heavier) motor with the lower kv.

So if my thoughts are correct, the 750W and 500W versions would be identical except for programming. Again, I don't know this for sure but I am 90% confident

Thanks Kepler. I appreciate your input. I do know that they are changing things all the time and I would imagine that every time they put out a new batch there will be some differences even if they are only minor. I see that some re-sellers are showing a C963 LCD display. I heard someone refer to a C965 but I have not seen anything by anyone else about that so maybe it was a typo.

I have not heard anyone mention yet if the LCD is easily removed for when your parking the bike somewhere other then home. I know that the kit is reliant on having the LCD attached to actually run and use but theft is an issue in many cities (like mine) and anything on or attached to a bike that looks like it may be of some value disappears (just like magic).

Shanman3us