Voicecoil's red, fully rigid commuter

[mingonn]

Hi Voicecoils,

I have 400 km up on my 20 bafang now, but my system is only 44.4 v and limited to 5.6 amps. I reckon your problems are two fold, first is wheel size and second is the current.

Going 20" requires alot less torque to get moving than a 26" (I am guessing you stripped the gears on take off), but getting a decent 20" bike is tircky. Easy fix in the sort term is to lower the controller current to reduce the torque going through your gears, you should still get the same top speed on the flat but your hill climbing and acceleratio will be effected.

I would suggest limiting the current to 5 amps to start with then keep increasing it till you start stripping gears again than back it off to the last setting. Its quite easy to solder in an external remote shunt, and if you use a screw clamp at one end you can just slide it up and down to increase/decrease the current draw....but if you have a CA then I am pretty sure you can set it there.

Hope this helps
Derek

 

[voicecoils]

Hi Voicecoils,

I have 400 km up on my 20 bafang now, but my system is only 44.4 v and limited to 5.6 amps. I reckon your problems are two fold, first is wheel size and second is the current.

Going 20" requires alot less torque to get moving than a 26" (I am guessing you stripped the gears on take off), but getting a decent 20" bike is tircky. Easy fix in the sort term is to lower the controller current to reduce the torque going through your gears, you should still get the same top speed on the flat but your hill climbing and acceleratio will be effected.

I would suggest limiting the current to 5 amps to start with then keep increasing it till you start stripping gears again than back it off to the last setting. Its quite easy to solder in an external remote shunt, and if you use a screw clamp at one end you can just slide it up and down to increase/decrease the current draw....but if you have a CA then I am pretty sure you can set it there.

Hope this helps
Derek

Thanks for checking in with your suggestions. I can't go to a smaller wheel. 36v nominal (44v hot of the charger) is a possibility but I would need a new controller.

The second gear stripping was not on take off, I'm quite sure. More likely it was accelerating from ~20 to 30kph up a bit of a hill. I can't be sure though.

I have two CAs. A stand alone one which can't be used to control current, and a plug in one. The plug in one does not plug directly into my controller, but I may try to wire it in to get the current limiting.

Was your bafang wound for a 20" wheel? mine says 26, 36v on stickers on the outside.

 

[docnjoj]

I run 48 volts in the Bafang and havent had any trouble with gears, but I also use a 20 inch wheel!. I think 72 volts may be be too much for it. Knuckles seems to do fine with 72, however the best thing may be composite gears. Steel is noisy and wear rapidly. Check with Knuckles because he really is helpful. Oh yeah! One steel and 2 nylon may be an answer! Lots of geared motors (P2A and P2b for starters) do this!
otherDoc

 

[johnrobholmes]

Knuckles doesn't have hills where he is either...


How much do you weigh VC? 72v is twice the rated voltage, not too much of a surprise that the gears got eaten up going up a hill, but I would like to see better gears for them as well.

 

[voicecoils]

Knuckles doesn't have hills where he is either...

How much do you weigh VC? 72v is twice the rated voltage, not too much of a surprise that the gears got eaten up going up a hill, but I would like to see better gears for them as well.

I'll go weigh myself now.

9.5kg for the batteries
20kg for the bike incl motor/controller
75kg of me

The rim+spokes+hubmotor+2 rolls of rimtape + tube + 2.2" specalised tire = 5.3kg. It is fairly heavy and the tires are quite grippy.

How's your rear bafang holding up? Your running under 50v right, and what amps with the castle creations controller? My experience of the nylon gears is not favorable at all. I can't imagine them handling off road riding at all.

Did you see my dimensions of the gears? Maybe your connections in the RC world could help you get hold of metal or tough composite replacements:
http://www.endless-sphere.com/forums/viewtopic.php?f=3&t=7031

 

[Freddyflatfoot]

VC,
I'm not sure which Bafang you are using, but mine is a 24v version, overvolted to 36v. From what I understand, these motors, as is, are good for 48v.
I think I have read elsewhere that if you are going to run 72 v on these or other geared motors then 1 gear can be replaced with a metal gear. This should reduce the load on all the gears and prevent them stripping, without creating too much noise. I think Team Hybrid have done some work with this on the Puma motors.
Another solution, is to limit the amps, as has already been suggested, even further.
If you pulled anywhere near 30A, then the motor input would be something like 2000 watts! Thats probably around 10X the rated capacity for the motor, and probably exceeds the design limits?
10A would be a more acceptable limit, and would still give you around 720 watts input, and would be more controllable.
The other thing to look at is riding style. If you use the motor from a standing start, you are putting maximum load on the motor. And when you climb a hill, you'll probably find that it is better to pedal and find the right amount of throttle to maintain your speed.
As for starting off, I avoid using power until I'm moving, usually above 10 kph.
Another benefit of limiting the current, apart from less strain, wear and tear on the motor, is an extended range from the battery pack.

On another note, as a copper, is to caution you on excessive use of power on an e-bike! Yeah, I know, it can be quite addictive, all that power!
But, bare in mind, that from a legal perspective, that an e-bike is a power assisted bicycle, that has an auxiliary motor to assist the cyclist.
If you are trying to have an electric motor bike by stealth, without license and rego, then I believe you are trying to operate completely outside the spirit if the law. It, OTOH, you are a cyclist who appreciates having the assist to help you along, and make commuting less of a chore, then I say go for it!
I'm not trying to be a wet blanket, just pointing out where we should all be heading in terms of having viable and safe e-bikes.
The main thing to consider is working within the original design constraints of the base platform we are using. (the bicycle)
Having made these comments, I would vote for a current limit of 8-10A, and then see if the motor/gears hold up to that power input.

Hope these comments are of some assistance to you.

 

[voicecoils]

Hope these comments are of some assistance to you.

Hi FreddyFlatFoot,

I really appreciate your comments, thanks.

Current limiting is something I'm looking into. I currently have a stand alone CA and can't limit current with it. I've bought a second hand plug in CA however and plan to solder on a connector on my ecrazyman controller when knuckles gets the instructions to me.

Another option is a controller suitable for use with just 1 battery pack (36v nominal) or two in parallel. My controller can't go below 40v so it's not an option.

One metal gear, or all composite gears are options I'm looking at. Even with current limiting, I'm not convinced at the long term reliability of the nylon gears. If you've seen them in person I think you'll agree they don't look capable of handling much torque at all.

My motor is a 36v version for a 26" wheel.

On my second outing, I managed nearly 6km before stripping the gears. The peak amps were only 17.75A and for the most part current was kept under 10A.

On the legal issue, firstly I think that the electric power assisted law as defined, is irrational. Especially the "peak" vs "continuous" issue. I would like to see the law promoting safe ebikes that can provide REAL assistance. However, I am interested in operating the bike as legally as possible, even with the present restrictive and unreasonable policy.

I enjoy cycling and do a variety of riding from commuting, shopping, weekend spandex-clad road riding, and a bit of MTBing.

My on-road ebike goals are:

* A bike that enables me to commute faster then pedal power alone and with less sweating. My commute to work is ~13km each way. On my last unassisted commute (on a singlespeed drop handlebar roadbike), my average speed was 21 km/hr with a max speed of 43 km/hr. It took me ~38min.

* A bike that I can load up with groceries and still pedal around the hilly area I live in. I plan to have a front and rear rack (not filled with any ebike components) ready to aid in shopping, moving things around, and generally replace car trips.

My ultimate aim is to exceed my current un-assisted performance. If I could average 30 km/hr with a similar max speed and arrive at work less sweaty I'd be quite happy. Doing so would provide me an 'assist' of ~10 km/h over my un-assisted average speed. I don't see this as trying to operate an electric motorbike in secret. When I ride my road bike at 55km+ no one bats an eye. On the other end of the spectrum I've seen those crap electric vespa type scooters with pedals riding with traffic moving at 15 km/hr and holding everyone up. To my mind they are the real legal concern.

Thanks for checking in with your comments. When I get my plug in CA working, and can use it to limit current I'll try setting it at 2.5A which would make the bike 200w peak compliant. I'd be curious what assistance it could actually provide. I imagine 8-10a would be much more reasonable, as you say.

 

[deecanio]

Hi VC,

sorry to hear you have had the peanut butter effect
im really surprised that happened just going uphill? the nylon gears we have in the pumas have had some issues but mostly from severe abuse not just a hill climb?
ALthough the reducing amps may help the gears i think you will need a better solution (forget smaller wheel too) - once you back off the power i think you will be underwhelmed with the power losses - 200w? forget that, wouldn't pull the skin off custard!!
I dont know too much about the bafangs but i would guess that steel gears is the way to go until you can get your hands on composite. Still as i say im really surprised (dissapointed) that your gears mushed just riding uphill - to give you some idea i mashed my nylon gears in the puma up to 30 mph and any hill you like and they held up, the only time i've mangled them is jumping the bike and landing with throttle on?
im going to uprate my own nylons to metal soon so i'll let you know how that goes but if i were you i'd try some steels especially if your more comfortable with changing them now.


Cheers and good luck mate,


D

 

[johnrobholmes]

I know a few gearcutters, and I might have to get some cut up in hardened steel. Only problem is that the hub shell will wear faster too.

I don't weigh much less than you, but I have had no issues so far running mine on high voltage. I have mostly stuck with 12s a123 though, which is around 36v nominal. I don't see more than 35 to 40 amps on the biggest of hills.


Gonna mull this over for a bit and see what I can come up with.

 

[Freddyflatfoot]

VC,
I commute on my trike at an average of 28 kph, will cruise at 35 kph, and top speed is 42 kph. And I have over 3500 k's on my trike!
I would think that you would get more than satisfactory performance at 48v, or 36v if you were overvolting a 24v motor.
And my trike is a tank, weighs somewhere between 32-35 kg, and I'm also around the 75 kg mark.
But for hill climbing, I reckon these motors rock! Even on really steep hills, I just enough power in to turn the motor on a bit, and away she goes, with me assisting of course!
My controller limits the amps at 14.8A, peak input power from the Watts Up, is around 540 watts, and i more than satisfied with the performance!
If you really want a good, reliable commuter, drop the voltage/amps, and look for a cruise speed in the mid 30's, and you should be more than satisfied with the power/speed. And if your battery pack can give you a 40k+ range, that should be more than sufficient for your 28k commute without over draining the battery.

 

[voicecoils]

I know a few gearcutters, and I might have to get some cut up in hardened steel. Only problem is that the hub shell will wear faster too.

I don't weigh much less than you, but I have had no issues so far running mine on high voltage. I have mostly stuck with 12s a123 though, which is around 36v nominal. I don't see more than 35 to 40 amps on the biggest of hills.

I've sent an email to a Sydney gear cutter to see what they say. I agree with your concern of the hub shell. The sun gear is an insert into the shell, hopefully of a tougher material.

Have you opened up your hub to check the gears JRH? If yours is really fine at 40v, 40A then I think either speed is the major problem. ie the gears just can't stay meshed properly at ~2,000 RPM. OR, there could be a defect in my motor. If the sun ring was not perfectly round, or even 1 tooth had a deformity it could be a gear chewer.

If the nylon gears are reliable in your setup, that will be great for quite a few users. If metal or composite gears can take the motor up to 72v, 30A reliably that will be sweet too!

 

[voicecoils]

Hi VC,

sorry to hear you have had the peanut butter effect
im really surprised that happened just going uphill? the nylon gears we have in the pumas have had some issues but mostly from severe abuse not just a hill climb?

D

Thanks D. I'm hoping I can work out a solution.

I was surprised too, especially the second time when I was trying hard to keep the amps down, mostly under 10a.

Did you see my post about the xlyte 5304 I got for FREE I'm pretty excited and it certainly helped me stay positive through my gear shredding

P.s Saw some pics from the "clash of the titans", looked like an awesome day and your bike looked great

 

[Nogwin]

On my second outing, I managed nearly 6km before stripping the gears. The peak amps were only 17.75A and for the most part current was kept under 10A.

I feel that speed at the higher voltage may be a problem, and that the gears may not mesh right or contact properly and therefore get eaten up. I run at 66V and top speed is right around 46km (~29mph). I have routinely hit amp draws over 35A, but for short/few second durations, but total Watts peaks at 2000W on daily commutes. I'm on mile 1000+ (1,600km) and no problems. If you want speeds over 30mph then please get the X5 motors and run them at 48v. I had a 5303 at 80V and I could hit 50+ mph on flats. I since then ran it at 40V. I have no desire so go that fast, but wanted something very light - hence the Bafang suits me well.

Nog

 

[voicecoils]

On my second outing, I managed nearly 6km before stripping the gears. The peak amps were only 17.75A and for the most part current was kept under 10A.

I feel that speed at the higher voltage may be a problem, and that the gears may not mesh right or contact properly and therefore get eaten up. I run at 66V and top speed is right around 46km (~29mph). I have routinely hit amp draws over 35A, but for short/few second durations, but total Watts peaks at 2000W on daily commutes. I'm on mile 1000+ (1,600km) and no problems. If you want speeds over 30mph then please get the X5 motors and run them at 48v. I had a 5303 at 80V and I could hit 50+ mph on flats. I since then ran it at 40V. I have no desire so go that fast, but wanted something very light - hence the Bafang suits me well.

Nog

What size are your wheels?

I am leaning toward agreeing with your assessment. Your performance is basically EXACTLY what I'm after. ~45km top speed would be great, good assistance up steep hills too.

I've built the bike up to be a commuter bike. The only non-commuter part of it are the tires which are 2.175" Specialized mtb tires, which are not nobby but ARE quite heavy and grippy and pump up to 100psi. When the tires get up to speed there is alot of momentum. Perhaps the tires grippyness and the wheel's high moment of inertia are hitting the little gears with alot of torque. Perhaps it's the motor trying to outspin the wheel which are stripping the gears.

I just got a 5304 (see my DH Team thread), but for commuting on the red bike I want something light but tough, well balanced, and room for carrying crap. My front and rear wheels weight nearly the same ~5kg each (back wheel has an internal gear hub) and I plan to centre the battery and controller weight in the front triangle. Then front and rear racks will maximise my ability to carry groceries, run errands, and commute without a backpack.

BTW, I ride a Pinarello Prince for fun and recreation so I'm not opposed to peddling. Commuting and utility biking has it's own set of requirements though IMHO. Especially when you don't wish to arrive at work completely sweaty.

 

[voicecoils]

VC,
Just another thought on the amount of power you are using.
It maybe be unwise to have that on your front wheel. There have been some nasty stories of front forks not being able to handle the torque. Ar you using any extra torque arms?
Personally, if I were trying to power a bike in excess of 1500 watts, I'd want that power at the rear wheel.
Just a thought.............................................

I've read about a few front fork failures. The fork is a rigid all cro-mo fork on a cro-mo frame. The fork is from Planet X and is renowned for being incredibly stiff and strong. Even so, due caution is advised, I agree.

I am not using proper torque arms yet, but have bought some 5mm stainless plate which I plan to make some arms up with. I talked about this earlier in the thread, but it's getting so long I don't blame you for not having come across it The hub has torque washers, and the large tires do soak up some vibration and impacts.

Power at the rear wheel is a better spot, especially for popping wheelies but I won't be doing that on this bike. I have a 8 speed internal gear hub in the rear wheel which makes a hub motor back there impossible. The internal gear hub gives me great shifting, shifting without peddling, and is completely sealed from the nasty outside world. Perfect for commuting and utility purposes. Having front and rear wheels very close in weight also aids in the balance of the bike. The heaviest bits, the batteries will be mounted in the main triangle.

 

[voicecoils]

another day another test

Last set of fresh nylon gears!!! 36v only for now. Packed with moly grease (3%) we'll see how they go...

I managed to mount my CETMA rack on the read bike without any fork modifications. I just used two U-bolt w/ plates and screws. Then put the rack strut on and screws a nylock nut on top. I'll see how it holds up to vibrations and loads. If it slips down I'll look to a better solution.


I temporary mounted the 36-72v 35A Crystalyte controller (in non-slip rubbery stuff) to the vertical part of the rack, and the cycle analyst too.

I had a run last night with 36v10a headway pack in a bag occy strapped down on the rack. The bike handled fine with the weight, just a bit heavy on the steering. But standing still it really does want to fall over (thanks to the fork angle) and it is a MEGA pain to carry up or down stairs. (queue Mark_A_W saying: "I told you so") :wink:

More on the actual test run in the next post...

 

[voicecoils]

I hooked the analogue Crystalyte 36-72v 35a controller up to the bafang and tried to follow Nogwin's wiring:
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=6241&p=95977&hilit=bafang+wiring#p93646

My sample of a BAFANG motor (from knuckles) to a Crystalyte analog controller 36-72v 35A looked like this:
Motor Controller
reverse jumper open

My motor wiring combo
Motor Phase -- Controller
B B
G Y
Y G

Hall
Motor Controller
pos pos
neg neg
B B
G Y
Y G

Other combos I tried did not get the motor moving (except one where it went backwards).

The combo I settled on worked but did seem a bit noisy and had high vibrations. I took it out on the street and as soon as I hit the throttle I was thinking "what the heck!". The whole bike was buzzing like crazy. The first thing I found was a loose water bottle cage bolt. A lot quieter after that. BUT still noisy. I proceeded to electrical tape down everything I could think of that might be making noise, brake lines etc... Controller and CA seemed very firmly mounted.

Today I'm going to go through the wiring combos again, and might take the rack back off and see if it is just transmitting vibrations through to the frame and causing all the noise. If so I'll try to isolate it with some bits of old bicycle tubes.

I only used 0.8Ah before I stopped riding. Too worried about the nylon gears and controller mis-wiring. It was loud enough that I didn't want to hit the throttle when passing people for fear of scaring them :lol:

It's raining today so a good chance to check my 36 wiring combos! But...I'm wondering if the crystaylte controller is just not the best match for the bafang. It does work, but could it be causing the bafang to operate with high vibrations?

 

[voicecoils]

just checked wiring.

Nogwin's wiring runs my motor smoothly, but backwards!

Will try Docnjoj's wiring now:

Halls are the same but he ran the phases:

Motor -- Controller
B Y
G G
Y B

EDIT: DOC's work! but it is loud. I'm going to try to sort out where the noise is coming from. Sounds like a power drill drilling screws into 2x4s. I'm thinking it must have been Doc's wiring that I ran with last night...

 

[johnrobholmes]

Could just be a loud ass controller. Is it harmonic frequencies or popping frequencies?

 

[voicecoils]

with doc's wiring I cranked the throttle no load...

and blew a 10A fuse

Before I had 10A max current set on the CA, this time I took it off. Seems like I'm having the same problem doc had. Dammit.

I'd like to know how nogwin has his set up. maybe I can get him to double check his wiring.

 

[voicecoils]

Ok, I've found the superior combo. (at least I think so! )

Nogwin's wiring with the 36-72v 35a crystalyte analogue controller jumpered to reverse (my key switch is broken).

Runs smoooooth at under 1A no load. DAMN the rain!

 

[voicecoils]

Could just be a loud ass controller. Is it harmonic frequencies or popping frequencies?

I would have described it as harmonic (noise from the motor). However I don't know what a popping frequency might sound like.

10A+ no load is just wack.

I think the combo I described in the above post is the answer. Road testing will tell for sure. I suspect nogwin has his switch turned to reverse or jumper jumpered, but we're running the same controller motor, and wiring now. mine is working with the controller in "reverse"

Motor sounds much smoother. Before it was sending vibrations through the whole frame.

 

[Freddyflatfoot]

VC,
I would be interested to hear how you like the Bafang at 36v.
I am more than happy to run mine at 36v, but then mine is a 24v model overvolted to 36v!
Cruise speeds above 30 kph are fine for me for my commute, and by keeping the speed down a bit, I also keep a tighter reign on my whr usage.

 

[johnrobholmes]

You should be able to swap two phase wires, and two sensor wires to achieve proper rotation and synch without the reverse on the controller. If you got it to work, no matter though!


A popping frequency is just that- a popping sound. When a controller is firing the motor wrong it can occasionally let out a POP when the phases un-sync and re-sync because of load changes.

 

[Nogwin]

I just checked the controller and the key switch is at the horizontal position pointing to red mark.

When I was getting the phase wiring figured out several months ago, the combo I posted was the only one to work smooth. Others made a crazy noise and amp load was 10+A at a few mph. So the wiring I have and the key switch in that position works well. There's absolutely nothing but smooth motor accel all the way to wide open throttle. No unusual vibrations or anything like that.

I hope this helps

btw - I should mention the 66v is really good for commuting and I get good acceleration thru 30mph. At 48v I was just at 20-21mph, and needed more for safer travels. I really hope your gears survive. Also plan to pull the motor apart and photograph my gears after 2000 miles which should be in a few weeks. (I ride about 50miles round trip 5 days per week)

Nog