New Bafang Crank-Drives

[spinningmagnets]

Kepler, I'm always sad when I read that Aussies have a 200W power limit (edit: 250W), do you think this drive is inconspicuous enough to "fly under the radar" when pedaling past most of the police on the street?

 

[Kepler]

Kepler, I am interested in how it performs on bumps and drops. I am interested in how it will perform on tight single track, which as you know require short bursts of power.

What happens if power is on when going over a bump or jump? On my DD hub it seems to be no problem but I wonder what happens to the chain when the wheel is up and then comes down suddenly.

Nice stealth bike, can't see the motor!

I have only done a bit of single track work with the drive but so far, it feels great. You pedal like normal with the PAS helping you out and then use the throttle to give you a burst of power when you need it. You do need to work both the gears and assist settings in unison to match the terrain though which takes a little getting use to. In regards to jumps, haven't done much testing on that front so I can't really give you any feedback on that side.

 

[Kepler]

Kepler, I'm always sad when I read that Aussies have a 200W power limit, do you think this drive is inconspicuous enough to "fly under the radar" when pedaling past most of the police on the street?

We actually have 250W now Lucky us.

Absolutely fly under the radar with this drive. A bike equipped with one of these drives wouldn't get a second look.

 

[Avigo]

Just to follow up on my claim on BAFANG, refer to the faulty coils which was cooked after only a week of running, ( see page 29) Bafang completely ignored me. They do not honour their product if you buy direct from a 3rd party via the net. But they will sell me replacement motor for AUD $450. After my testing l will scrap this project and stick with geared hub.

SO..LET THE BUYER BEWARE. :-( :-( Amy from GEB did her best to help me.

 

[Rollodo]

Just to follow up on my claim on BAFANG, refer to the faulty coils which was cooked after only a week of running, ( see page 29) Bafang completely ignored me. They do not honour their product if you buy direct from a 3rd party via the net. But they will sell me replacement motor for AUD $450. After my testing l will scrap this project and stick with geared hub.

SO..LET THE BUYER BEWARE. :-( :-( Amy from GEB did her best to help me.

Pics?

 

[EVTodd]

Just to follow up on my claim on BAFANG, refer to the faulty coils which was cooked after only a week of running, ( see page 29) Bafang completely ignored me. They do not honour their product if you buy direct from a 3rd party via the net. But they will sell me replacement motor for AUD $450. After my testing l will scrap this project and stick with geared hub.

SO..LET THE BUYER BEWARE. :-( :-( Amy from GEB did her best to help me.

Wow. That really stinks. Hard to believe they wouldn't replace it under warranty. I can see if the whole motor was abused and overheated but that really looks like it shorted in one spot.

These drives are obviously getting very popular, you would think they could afford to help a customer out. Lame...

 

[John Bozi]

Isn't suppose to cutout if it is overheating?

 

[Kepler]

Yes, Avigo's situation does suck. I think it should be GEB's responsibility to replace the drive though as they are the seller of the product. The evidence is quite clear that the burn is localized, and not from overheating.

I am not convinced these drives have an overheat cut off though but will probably get a closer look at Avigo's motor in the near future to confirm. Looking at this failure, I don't think overheat protection would have made much difference.

We can only hope this was an isolated incident but the number of dives now getting out there, we will soon hear if there are other similar failures.

 

[Tom L]

All done. Had to borrow a C-wrench / hook wrench from my LBS to cinch up the BB lock rings.

Can you spot the problem? http://i.imgur.com/hpv63Jw.jpg

Unfortunately I had to use the lowest gear to get up my drive and the derailur stuck there because the chain is too short. So I just went for a quick up hill test ride in first. I like the pedelec assist - move over Steve Austin!

My LBS is closed for a couple of days so I will do a proper review and post my hydraulic ebrake solution after I lengthen the chain and go for a proper ride. First impression is that this is going to get me on my bike a lot more often.

 

[Melbourne]

All done. Had to borrow a C-wrench / hook wrench from my LBS to cinch up the BB lock rings.

Can you spot the problem? http://i.imgur.com/hpv63Jw.jpg

Unfortunately I had to use the lowest gear to get up my drive and the derailur stuck there because the chain is too short. So I just went for a quick up hill test ride in first. I like the pedelec assist - move over Steve Austin!

My LBS is closed for a couple of days so I will do a proper review and post my hydraulic ebrake solution after I lengthen the chain and go for a proper ride. First impression is that this is going to get me on my bike a lot more often.

1. yellow reflectors on wheel
2. rear derailiers

The bike and cellman battery looks cool....looks like ktm/bosch system... wish i have waited for his battery.... how much shipped to aust and what size? Plan to put my bbs01 kit on a cannondale lefty badboy with cellman battery.... would look awesome..

 

[Tom L]

1. yellow reflectors on wheel

Required by law for riding at night here. I do not want to attract any undue attention.

2. rear derailiers

Yeah, tight as a nuns...

The bike and cellman battery looks cool....looks like ktm/bosch system... wish i have waited for his battery.... how much shipped to aust and what size? Plan to put my bbs01 kit on a cannondale lefty badboy with cellman battery.... would look awesome..

48V 11.6Ah, $140.00 USD shipping for the battery and motor from Lectric Cycles in the US.

 

[Spacey]

Man if you all new the amount of hassle I am having trying to get my motors sorted out with Amy. Really feel like I am pushing noodles up a stream.

 

[teslanv]

Man if you all new the amount of hassle I am having trying to get my motors sorted out with Amy. Really feel like I am pushing noodles up a stream.

I have had great experience with lcrewse. Great communication so far, and shipped promptly.

 

[Kepler]

Just another observation with the standard throttle setup and the dead section during the first half of rotation.

This dead area is of great assistance when changing gears. So basically when you want to change gears, you just hold a bit of throttle on as you carry out the change. This takes the load off your gear system and allows for a nice smooth gear transition.

 

[Kepler]

I have had the opportunity to give the drive a good workout on a variety of single track over the past 2 days. Clocked up 60km of purely single tack with with plenty of tight twisty uphill together with lots of bone jarring tree roots, logs and ruts. Have had an absolute ball and now really understand what a mid drive is all about. The way the bike handles and skips over the rough stuff is such a nice change from even a light weight geared hub motors in this environment.

Economy was great with each of the 30km rides using around 250 Whrs. Sure, I worked quite hard during these rides but felt really connected with the bike with it feeling really natural to pedal hard when needed. Rode with 2 mates today, one on a Fighter and the other on a Bafang BPM hub downhiller conversion. I managed to stay with the Fighter for most of ride with the Fighter only pulling away on the flat straights. Most of the ride was on setting 5 (out of 9) which was plenty of power and speed for the terrain. Spent most of the time with the PAS but used the throttle for that extra burst when needed. Extra handy on those uphill Bern's. Got the technique down pat with changing gears when under pressure. Just a matter of a bit of light throttle, change to the required gear and either release to re engage PAS or give it some more throttle for a burst of power when needed. With a bit of practice, it becomes very natural and fluid.

No problems with motor temp with the motor housing only reaching luke warm on even the hardest part of the ride.

In these conditions, the drive really shined and was an absolute joy to work with. However, the drive did spent most of its time at a conservative power level of 250W to 750W. Having the gear ratios available does make all the difference however I doubt this small motor would stand up to extended periods of setting 9 full and throttle operation.

 

[dan974]

Have had an absolute ball and now really understand what a mid drive is all about. The way the bike handles and skips over the rough stuff is such a nice change from even a light weight geared hub motors in this environment.

I moved to the GNG 650W (chain) when I broke the 4065 axle (in the air right now ) and yes I can say midrive is another story...I could climb sick hills and downhill+ jumps in enduro during 4h with 16amp inside and using the throttle with small accelerations to limit amp...all I have done is using 7.5wg oil instad of 5wg in my front fork to compensate the added weight, you can even order replacement pieces in case of pedal rock shock...
My buddi is very interested with this bafang and the joy you seems to have is very prometting...thks fro the review

 

[John Bozi]

Thanks Kepler, appreciate this info.

1. can you take a close up pic of what you are carrying your battery in? what is it?

2. Must you have throttle to get full power out of the motor? Or vice versa, must you have pas installed to get full power out of it. I find throttle makes getting up parts where you can't get ground clearance to pedal are huge advantage.

3. Although I wish I was allowed to buy an FS bike for this drive, I've got a carbon hardtail I can't sell for what it's worth. Would the stiffness and lack of suspension be too much for the drive, just sort of unsprung hub weight problems again...

thanks, keep your pics and reports coming...

luv to see a vid

 

[Tom L]

I got sick of waiting for my longer chain to arrive and went for a short ride this morning. I only managed to accidentally shift to first a couple of times and it came unstuck under load. 2nd through top shifted fine.

To start with I used PAS0 which is throttle only. Kepler there is a large dead band at the beginning of my throttle too and I agree with your idea that this is to make shifting gears easier. The rest of the throttle movement is proportional. The Lectric Cycles programming of an unlimited throttle in all PAS modes did not cause any dramas, it does not come on too strong though I did do a couple of unintentional but easily controlled wheelies going up hill. I did continually find the motor outpacing my legs in lower gears and had to shift up often to keep up.

Along the flat in top gear I could get somewhere around 45 to 50km/h WOT with minimal peddling. The lack of resolution when setting the wheel diameter makes the speedo slightly inaccurate. I measured my wheel diameter sitting on my bike with the 2.5" Hookworms at a comfortable pressure and it didn't quite come out at an integer value (which is all you can set). An old bike computer I have is more accurate though I forgot to reset the wheel diameter on this after changing the tyres. Hence the uncertainty.

I found riding in PAS2 to PAS3 (of 5 programmed levels) very comfortable with a medium to low cadence. A slight twist of the throttle in it's dead band or a dab on my custom ebrakes (details here: http://www.endless-sphere.com/forums/viewtopic.php?p=836334#p836334 ) enabled smooth changing of gears. I found PAS4 to 5 was outpacing me and I had to shift up.

There's a 1km long hill that peaks at 14% grade between me and my local shops. This is a pain to walk up but in PAS3 and 2nd to 3rd gear I was cruising up with light peddle assistance at 10 to 15km/h. The bottle battery is not high powered and was sagging a bit under load when climbing this hill but quickly recovered at the top. I forgot to check the motor temp at the top (having too much fun).

I have no way of measuring power consumption but after a 15km ride (I was amazed I'd covered that much ground in such a short time) through some very hilly terrain with light to moderate peddling the battery indicator was showing somewhere between 50 and 75% remaining (of 11.6Ah).

I launched off a few curbs at speed and everything seems fine but I dont think the bottle battery attachment will take too much of this sort of abuse. I'll simply avoid doing that until I can work out something additional to reinforce the two bottle attachment bolts.

Amazingly I found I can get to the supermarket and my work (both about 2 to 3Km away from my house) faster on this bike than I can drive there, as I can take shortcuts through bike paths and bush tracks.

For my short but excessively hilly commutes this motor and battery combination is a winner.

 

[Kepler]

Thanks Kepler, appreciate this info.

No problems

1. can you take a close up pic of what you are carrying your battery in? what is it?

I use a Topeak compact Handlebar bag. http://www.chainreactioncycles.com/...me=Australia&gclid=CLGvn8P10bsCFU1fpQodVDYA7g
They are a nice compact size and can squeeze up to around 400Whr of batter into it. On this bike I have have 4 x Turnigy 5ah 6S packs in there. These fit ok but I think Zippy compacts 5.8ah 6S are a better choice for this bag being lighter and smaller in size. These are my battery of choice at the moment.

This bag has a really robust mount and handles the weight no problems even when riding in the rough stuff

2. Must you have throttle to get full power out of the motor? Or vice versa, must you have pas installed to get full power out of it. I find throttle makes getting up parts where you can't get ground clearance to pedal are huge advantage.

Yes, throttle is the only way to get full power out of the motor and full throttle power is only available on on the highest setting (unless you get it specially programmed as with Tom L). Each of the PAS settings seem to be about 60% of the available power via the throttle so even if you are in a low power setting, you still get a proportional boost through the throttle. In relation to the PAS, with the standard programing, you have no choice, it is always installed. However, as soon as you touch the throttle, the PAS is overridden. So no problems using throttle only if you need the ground clearance.

3. Although I wish I was allowed to buy an FS bike for this drive, I've got a carbon hardtail I can't sell for what it's worth. Would the stiffness and lack of suspension be too much for the drive, just sort of unsprung hub weight problems again...

I don't think stiffness would be a problem even in a hardtail for the drive however it is very unlikely you will be able to fit the drive to a carbon frame. There simply won't be enough clearance in the bottom bracket.

 

[Kepler]

Avigo, dropped off his burnt stator for me to have a look at today.

First impressions were how neat the assembly has been designed with a nice PCB and central plug for the halls



The actual stator assembly is tiny and I can confirm that there is no temperature thermistor embedded into the windings.



View attachment 8

First job was to remove the Hall sensor PCB. With the aid of a solder sucker, this was quite straightforward to do.

View attachment 7

The actual stator is press fitted into the housing and being a blind press fit, there is no way to simply tap it out. To remove the stator, the housing would need to be heated and the assembly then tapped against a wooden post and use the weight of the stator to drop it out from the housing. Not much heat was required with the powder coating not affected by the heat at all. The trick is to get the heat in quite quickly and evenly so it doesn't transfer to the stator lamination. A few solid taps and the stator dropped out nicely from the housing.





View attachment 5

Close inspection of the winding shows a very localized failure. The failure certainly doesn't look to be from running too hot as most of the winding coating is bright and without any discoloration at all.



With the stator removed so the under side could be inspected, it was clear that a winding short had occurred to a point whereby there was burnt wire splatter deposited on the inside of the casing. IMO, part of the winding insulation was damaged during the winding process which then ended up shorting under high load.





Actual weight of the stator is just over 800 grams so not a lot of copper mass there.



So now with the stator removed, we need to come up with a plan to get this stator rewound and avigo back on the road with this drive. Unfortunately I have no experience re winding motors however I know there are plenty of people on this forum who would have no problems with this job. I am open to suggestions. First plan is to take it to a professional motor re winder and get a quote. If this proves to be too expensive, then hopefully with some help from experienced members, we can re wind it our selves. Written in black marker on the side of the stator is CA9T. I presume 9T stands for 9 turn however no idea what CA stands for. Any assistance at this point would be greatly appreciated.

 

[neptronix]

Thanks for the stator pics.

Man, they coulda stuffed so much more copper and magnet into the whole assembly..

 

[Lightning_boy]

I apologise if this has been dealt with in the previous 33 pages of postings; I have read them all but I simply can't remember: has anyone used the BBS-01 or BBS-02 in a single speed set up, and if so, what's it like?

 

[spinningmagnets]

Wonderful pics, Kepler...thanks for posting that. Could you do me a huge favor? I'd really appreciate it if you measured the width and length of the stator teeth, and the ID of the stator, plus the dimensions of the bearing that sits down in the hole?

The current understanding of a forensic deciphering of these motors suggests that there are two stator-widths (each width allowing a certain max amps), and then two Kv's available (same RPM's per two available voltages). I can imagine that the "CA9T" markings are winding instructions to some bored stator-winder on the Bafang assembly line. If yes, then the remaining information needed (after seeing it's for a 9-Turn Kv), would be which diameter of wire, and how many strands will be used "in hand".

Or....for all I know, it could be the initials of the guy who wound it ("Dammit, CArl, we got another warranty return that you made...you better get your shit together, man)

 

[tomtom]

Hi guys,

Its my first post here and VERY OT - but i just find this interesting picture of bosh middrive so just for your info..

 

[Spacey]

Like a multi geared setup .... only you don't change gear.