New Bafang Crank-Drives

[lazy_mosquito]

Hi i forget to introduce myself,

Tried it already but the post dissapeared in the big nowhere called internet.

I am Pieter and converting a bullit cargo bike to an e-bike. At this moment the BBS02 500W or 750W is my engine of choice. Only problem is that i will have to mount it at the bottom of my frame, so ground clearance will be decreased to +/-16 cm. I will also use a Nuvinci N360 and hope it will coop with the torque of the Bafang. Further i will use Tektron Audigi e-comp hydraulic brakes. They have e-switches which comes in handy for cutting the power when braking.

After reading all this different posts and foras i still have some questions (actually i have more questions then before i started reading )
I need some strong batteries because i would like to drive at +/- 20 mph for about 80 miles (thinking about 48V 30ah) i am torn between ncm batteries or a123 20 Ah pouches. Suggestions? (i will not use lipo's although they are great, they also make great fireworks and i have to charge them unattended)
Anybody knows an alternative for the Bafang (but need the same stealth, pricerange, middrive)
I have found some posts where people are referring to bafang BBS01 with external controllers, but i can't find any thread or post which explains how to use an external controller with the bafang: if somebody knows a link or knows somebody who has already made this mod, please give me a hyperlink

thanks in advance,

Pieter

 

[PaulD]

PaulD,

On MrBill's blog, it says he got a faster time in 2011.

Yup. He kicked your butt. He was over 3% faster, and used just over 93% as much energy.

I think there is room for improvement for sure. I don't know if I could make up 3%, but I could:
1) Repackage batteries for better handling (the aforementioned death shimmy forced me to slow to 5mph 3-4 times during the race to regain control) also, I was more timid on the descents because of this.
2) Wear more aero clothing - I planned on taking off my rain jacket since it didn't rain, but I was way too cold. I couldn't take my hands off the bars to tighten up the cuffs due to the shimmy, so it was billowing in the wind, along with my water pack.
3) Don't stop for as long. I stopped for a minute at each checkpoint to rest my aching back (gotta train with those aerobars for more than 1 ride before the race!) I also drank way too much water and stopped to pee for a solid minute.
4) I didn't use enough capacity in the first 1/3 of the race. I realized this, and gassed it for the remaining 2/3rds. It would have been more efficient to go faster for the first 1/3rd and keep it consistent for the rest.
5) Less wind. As mentioned in the race report, the wind changed direction about 3 hrs after I started, so I was in a headwind for 3/4 of the race.

 

[Geebee]

A NoCom would solve most of those issues and add quite a few kph to your top speed

 

[neptronix]

Now available for a low, low $99999999999999999

 

[greenspark]

i am torn between ncm batteries or a123 20 Ah pouches. Suggestions?
Pieter

Contact cell man http://endless-sphere.com/forums/memberlist.php?mode=viewprofile&u=14820 and ask for advice. He makes both batteries, and now has both the 350W BBS01 and the more powerful 750W Bafang mid-drive.

 

[Warren]

Geebee,

"A NoCom would solve most of those issues and add quite a few kph to your top speed"

[The hour record for recumbent bicycles without aerodynamic fairings, set by Francis Faure in 1933, was broken in 2007 by Sean Costin, who covered 48.80 km (28.46 mi) on the 382m outdoor concrete velodrome in Northbrook, Illinois. Costin then rode 47.89 km (29.76 mi) on the 250m indoor wooden velodrome at the ADT Event Center in California. He rode a recumbent made by the Polish manufacturer Velokraft (model name NoCom), which he converted to a fixed-gear for the indoor event.]

Here is an awesome electric assist also built by Kamil Manecki of VeloKraft.

http://www.youtube.com/watch?v=cihVD_gtrkY&feature=plcp

 

[Warren]

PaulD,

"I was more timid on the descents because of this....I stopped for a minute at each checkpoint to rest my aching back"

Aerobars are an ergonomic and handling disaster. I have raced on them for an hour at a time. After months of practice...they still sucked. I once made a small sprung pad, mounted to the top tube, that I could rest my weight on my breastbone on, and ran a straight, flat handlebar on a 1" reach BMX stem. I could ride sitting up like a normal flatbar bike, or get prone on the pad, and steer comfortably with my arms tucked up under, like the Obree 'egg' position.

http://ttbikefit.com/blog/wp-content/uploads/2009/04/obree.jpg

It worked great, very stable. I could even ride in that position at 3 mph, and turn a tight U turn in the road. Try that on your aero bars.

 

[spinningmagnets]

Warren, that Velokraft is an interesting E-scooter...

 

[rodgah]

I have a fitment question for you 750w owners....I have looked at all of the photos but cannot see it clearly.....

Is the face that butts up against the BB recessed around where the BB outer face meets it? On the pictures of the 350w it looks like it is flush, but the 750w seems to look like there is a recessed ring around it. In other words (ignoring the rest of the drive interfering) if there was a BB diameter hole in a flat plane would it mount properly?

Also in regards to chain line.....would a 150mm rear end help? What is the chainline measurement from center of bike with the factory chain ring.....I think 150mm rear end is supposed to be 55mm?

Kepler nice battery enclosure, have you thought about making endcaps out of cnc'd hdpe for the popular plastic bunnings downpipe?

 

[beazee]

I've a Bullitt Cargo Bike with NuVinci hub at the back and a dynamo in a front wheel. Living a quite a hilly place and looking around for a bit of assistance. Previously had a bike with 36V 250W geared, throttle controlled, front hub motor to pull the trailer but since moved to cargo bike missing the assistance I had before, although the 250W motor was a bit underpowered on climbs with 40 lbs bike + 200 lbs cyclist + 60 lbs trailer+passenger.
Am I right assuming 500W or 750W BBS 02 would be perfect for the application? Not looking for a speed, rather for a good pace climbing (ca. ~70 rpm cadence) with sometimes heavy loads.

I've finally put an order for BBS-01 36V 500W (25A) 46T C961 with Amy from GEB.
It's now advisable to source out NuVinci 21T sprocket before the unit arrives.

 

[billsy]

OK having read thru the whole awesomeness of this discussion I’ve decided to jump on the Bandwagon and ordered a 750W drive from AliExpress. My plan is to upgrade/de-Frock my Mac powered Big-Hit FSR which I built a couple of years ago for off-road use. I really like the idea of eliminating the unsprung weight from the rear wheel. However before removing the Mac, I intend to have a bit of fun with both motors installed on the bike.

I recall someone saying the Bafang wouldn’t fit ‘most Specialised full sussers’ but apart from grinding down the ISCG mounting and omitting a lock ring for the wider BB, it looks like it should fit this frame so fingers crossed.

 

[Chalz]

Billsy,

I recently mounted a 750W Bafang on my Big Hit. I had to remove a very small piece of aluminum that held on the chain guide from the frame. I also had to very slightly remove some material at the end of the BB threads on each side. The motor then fit great and sat up higher than the chainring. The bike went 32 mph at full throttle and 25 mph when peddling.

My issue is the battery. I bought this battery.
http://www.conhismotor.com/ProductShow.asp?id=346

The voltage drops from 50V to 41V in two minutes of driving. The voltage sag is extreme. Every time I charge the battery it gets worse. I'm trying to deal with conhismotor over it, and having trouble getting them to return my emails. That is real bummer. I'm now considering buying the same battery from here.

http://gebattery.en.alibaba.com/product/1352732656-212516823/Hot_sale_48V_20Ah_electric_bike_li_ion_battery_with_factory_price.html

I plan to weld a cavity for this battery right in the middle of the frame. This way I can easily pull the battery out and charge it in a safe place.

Chalz

 

[billsy]

Chalz

Thanks for the info on the Big Hit. Are you saying you had to remove some material from each face of the BB i.e. make the shell narrower? How much did you need to remove and why? Edit. You got any pictures?

I’m well impressed with the top speed you are reporting, that’s plenty fast enough for my local trails!

Real shame about your battery. That amount of sag is going to kill it rather quickly. Have you thought about assembling your own pack? I’ve got 16 x 12ah headways in my frame with a Ping high rate BMS, dead easy.  Failing that, have a chat with cell_man (paul) he’ll sort you out.

 

[speedmd]

Is the face that butts up against the BB recessed around where the BB outer face meets it? On the pictures of the 350w it looks like it is flush, but the 750w seems to look like there is a recessed ring around it. In other words (ignoring the rest of the drive interfering) if there was a BB diameter hole in a flat plane would it mount properly?

There is a small recess in the gearbox housing. I used a freewheel / bb cup spacer so it would mount flush as my bb face is flush with the adjacent swing mount. It was around 1.5 mm thick and it tightened up nice and square with it.

 

[speedmd]

PaulD,

"I was more timid on the descents because of this....I stopped for a minute at each checkpoint to rest my aching back"

Aerobars are an ergonomic and handling disaster. I have raced on them for an hour at a time. After months of practice...they still sucked. I once made a small sprung pad, mounted to the top tube, that I could rest my weight on my breastbone on, and ran a straight, flat handlebar on a 1" reach BMX stem. I could ride sitting up like a normal flatbar bike, or get prone on the pad, and steer comfortably with my arms tucked up under, like the Obree 'egg' position.

http://ttbikefit.com/blog/wp-content/uploads/2009/04/obree.jpg

It worked great, very stable. I could even ride in that position at 3 mph, and turn a tight U turn in the road. Try that on your aero bars.

Hi Warren

Did your arms cramp up bent like that. Does look fast. Sounds like pauD had the same issues many TT setups get into by trying to get too low, weight too far forward and reach set much too far. When this happens with a flimsy bar setup, flexy fork and slightly loose head set, it is a recipe for a shimmy machine. I like the spinaci style clip ons beast of all I have tried which allow a bunch of more aero positions without having to go full tilt or canabal. They also handle much better.

 

[Warren]

speedmd,

"Did your arms cramp up bent like that."

No. There is no weight on them, and you could take one hand free at a time and shake them out, just like when sitting up, without getting out of the prone position. I used part of an old urethane stem for the pad mount.

http://www.bikepro.com/products/stems/stems_jpg/n_girvin_stem.jpg

You could lift your chest off the pad occasionally to relieve pressure there. I thought about making them, but highracers are a much better solution.

 

[Kepler]

I have a fitment question for you 750w owners....I have looked at all of the photos but cannot see it clearly.....

Is the face that butts up against the BB recessed around where the BB outer face meets it? On the pictures of the 350w it looks like it is flush, but the 750w seems to look like there is a recessed ring around it. In other words (ignoring the rest of the drive interfering) if there was a BB diameter hole in a flat plane would it mount properly?

Also in regards to chain line.....would a 150mm rear end help? What is the chainline measurement from center of bike with the factory chain ring.....I think 150mm rear end is supposed to be 55mm?

Kepler nice battery enclosure, have you thought about making endcaps out of cnc'd hdpe for the popular plastic bunnings downpipe?

speeddmd answered the first part of your question.

In relation to the chainline, it is 50mm on 68mm BB. I think the 150mm rear end will be a help with keeping the chainline in check especially if you need to add a spacer the drive to help clear the chainring.

Haven't thought about the downpipe option at this stage. I make a lot of custom parts from machining plastics so it is worth some further investigation perhaps

 

[Kepler]

OK having read thru the whole awesomeness of this discussion I’ve decided to jump on the Bandwagon and ordered a 750W drive from AliExpress. My plan is to upgrade/de-Frock my Mac powered Big-Hit FSR which I built a couple of years ago for off-road use. I really like the idea of eliminating the unsprung weight from the rear wheel. However before removing the Mac, I intend to have a bit of fun with both motors installed on the bike.

I recall someone saying the Bafang wouldn’t fit ‘most Specialised full sussers’ but apart from grinding down the ISCG mounting and omitting a lock ring for the wider BB, it looks like it should fit this frame so fingers crossed.

Your Big-Hit is an awesome bike. You are going to love it even more with the middrive. I really hope you can get the chainline spot on as this will be the difference between it being good and being great.

 

[billsy]

Thanks Kepler. I really should take some measurements to see whats what. Just looking at the Bafang drawing, it looks like the centre of the chain ring is 16mm from the face of the bottom bracket. Do we know if that includes the recess that speedmd mentioned earlier?

 

[Kepler]

The recess is very small, maybe 0.5mm at most. Just stick with the 16mm measurement from the face of the BB on the chainring side to the centre of the of the chainring.

 

[speedmd]

Recess was just over 1mm deep on mine. A 1mm shim was not enough to keep the case from hitting hard on the adjacent frame metal on mine. Best I could measure, with the calipers was .050"-.052". Just enough to be annoying if you don't have spacer shims handy.

 

[Kepler]

I would need to remove my drive and re measure to confirm.

 

[Kepler]

After using a brake cutout switch on the gear selector to kill power when up changing, one of the undesirable side effects is the delay induced before PAS comes back on after you have selected the gear. I would prefer PAS to come back on without delay once the gear has been selected.

So to try and get around this delay, I plan to try a different method of throttle cut rather than using the brake switch.

As we have found, the first part of the throttle has a dead band that cuts power to the motor however once the throttle is released, PAS is instantly re activated as opposed to the brake switch which ramps the PAS back on once the brake is released.

The idea is attach a micro switch to the gear shifter and wire the micro switch into the throttle circuit with an added voltage divider. The Micro switch will send an output that simulates a low throttle signal to the controller and hopefully cut out the motor when activated. This will be added to my throttle button circuit but should also work with the standard throttle.

Might need to experiment with the voltage output a little bit but I think it will be a better system then using one of the brake switches. Also means you can still use both brake switches if desired.

 

[fechter]

You could use a little trimmer pot and make it adjustable.

 

[dirkdiggler]

Got a ride in yesterday with the 750w on a Gary Fisher Sugar. Did my usual route, but there is still slush, ice and mud on it. This makes it difficult to compare on my battery running times and pace with the hub motor. It will be a while before the trails are lacking any snow or mud. My pace was slower than normal but the battery was a bit better than the 1000w hub motor. We will see in the summer how comparable they are. I do really enjoy the weighting, almost like a normal bike. I am still having trouble wrapping my head around the shifting and putting the bike in the correct gear for myself and the motor with PAS. Then adding the use of the throttle. Too much going on at one time! The hub made it easy because I would just put it in a gear I could pedal and use the throttle for the rest. Now I've got to be in the correct gear for the motor, correct gear for me, correct setting on the assist and try and steer the bike at the same time. I guess it will take a bit of work to get it there, I'm just not used to it. Probably shouldn't be taking it out on technical trails with mud and snow quite yet. I might try and focus on either throttle or PAS next ride. Then mesh the two when the conditions improve. Still more fun than pedaling all by myself. I wouldn't walk that trail right now.