Lightweight/discrete Q128c commuter build on a road bike

[molybdenum]

I'd like to see what washers/spacers you have between the cassette and dropout.




My 9 spd cassette fits my Q128c with a rounded nut securing the motor to the axle protruding slightly. You can see the rounded nut just behind the washer just inside the dropouts. I used a fat washer to minimize the amount of bruising to the dropouts, as this rounded nut is a very poor fit to any frame dropouts.
The clicking might result from a bit of pressure on the freewheeling mechanism that can be relieved by adjusting washers/spacers? or perhaps by adjusting the cassette securing nut - tightening or loosening?

 

[-dg]

When I only did the axle nuts up loosely there was no click. When I tightened them right up however the click came back! Loosening off one nut (hand tight still) led to the click disappearing.

That is interesting. Does it matter which nut you loosen?

Some guesses to check:

- missing spacer so axle nut load is being taken on the bearing
- nuts/jam nuts not tightened against each other
- bad bearing

-dg

 

[Chalo]

Take the bike to a shop and have the dropouts spaced and aligned correctly. It is likely to fix your problem, but it's a good thing to do even if it doesn't.

 

[ModeratelyFastF]

Thank you for the ongoing help, it really is appreciated. I feel like it's so close to working!

Some other data points:

• The first time I installed the wheel I didn't put the washers in that go inside the dropout. Still clicked, but it fit perfectly with no need to spread the dropouts.

• It stops clicking if the nut on the cassette side is loosened off.

• When I had the wheel out of the dropouts I could still feel a faint tick as I rotated the axel by hand. Once I took the cassette off, undid the freehub nut, and put the freehub nut back on the tick went away.

• When I put it back together I did put the washers in on either side inside the dropouts (see pics). This required me to spread the dropouts by the width of the two washers (4mm total?).

• Before I tightened the nuts back up there was no clicking. Once it was tight the clicking came back.

• I'm now also hearing a faint 'pinging' noise when the wheel rotates, numerous pings per revolution, which sound like its coming from the spokes.

• At the moment the nuts are at about the minimum tightness where I feel it would still be safe. Now it is only making a ticking noise occasionally.

Is it possible it's actually a spoke shifting on the hub? But then the tightness of the axle nuts should have no affect on that. The wheel was built by a specialist wheel builder and was pre-stressed.

Perhaps I should take it to the LBS...

 

[ModeratelyFastF]

Update: loosening off the nuts has mostly eliminated the click. Now it is faint and only heard when I'm on the bike and peddling (can't hear it coasting anymore, or if I peddle it unloaded).

Based on the above I think I'll just monitor it and get it looked at if it's still occurring after a few extended rides - perhaps everything just needs to bed in?

In any case the test ride was very promising: I've limited the max current to around14 amps and I only use peddle assist (apparently the throttle isn't subject to this limit and I don't want to overheat anything). With a bit of pedaling I could make it up the steepest hill I need to tackle at 30kph (above the 50% unloaded motor speed of 23kph). At pedal assist 4 it cruised at 40kph, and at pedal assist 5 (which came up as 650 watts as reported by the controller) it cruised at 45-46kph, with me putting in around 150 watts or so.

 

[ModeratelyFastF]

Must be time for a photo! Here's how things currently stand:



My goals for this build were for a lightweight/discrete commuting bike that could assist me to increase my average speed. Is it lightweight? Total added weight was 7kg, so I hesitate to give myself a pass there, although it doesn't feel heavy when I ride it so perhaps it is just a pass. Discrete? Well it doesn't scream ebike to me, however that frame bag is hard to miss! In my neck of the woods a rack and panniers would be much more discrete as I see them everywhere, however that involves putting the full weight of this conversion on the rear wheel. So perhaps it is just a pass here to. Impact on my average speed? Well I can now ride up most of my hills at 30kph, and easily cruise at 40kph on the flat using about 300-400 watts, so definitely a pass there!

Current issue: is my controller going to overheat? Here's how things look:



So yes the controller is in a bag with little opportunity to shed heat. I note molybdenum has been successful running his controller in a bag:

I hide my external controller in a small under-seat bag, which is a no-no but I'm only pulling 200-300W so it doesn't overheat even on the hottest days.

I do have a possible solution though: adding grommets to the sides of the bag inline with the controller, and an exit port at the back to create a wind tunnel affect when I'm riding to get some air moving past the controller. Something like three of these on each side of the controller, with a hole at the back to let the hot air out:



Realistically though it would not move a significant amount of air.

The alternate solution is to add a temperature sensor to side of the controller and just monitor the temperatures, dropping power if it ever overheats.

One like this could be put inside the bag which would sound an alarm if things started to overheat (for less than $10 bucks):
https://www.ebay.com/itm/Digital-Al...209193?hash=item2aa30dae29:g:w~gAAOSw2Ptap0P0

One like this could even be mounted on the handlebars to provide real-time monitoring:
https://www.ebay.com/itm/9Mini-Digi...852478&hash=item3d5d6eaa1f:g:2aQAAOSwHG9asPyZ

So my inclination is to just add a temperature monitoring probe, set an alarm, and throw it in the triangle bag. Thoughts?

 

[molybdenum]

Nice build! Where's the motor

Although my battery is mounted to the downtube, I have a rear rack with pannier bags and travel with 5-10 kg in these bags every day. It's not so bad for handling that if I didn't need to carry gear to work, I would be tempted to put the 4kg battery in there and be done with it.

I've also been tempted to mount a rigid plastic case to the handlebars to contain the battery. For a small 14S5P rectangular battery, this would be more discrete than a triangle bag and having ridden bikes with handlebar mounted baskets, it doesn't affect steering unless you're dong DH stuff.

My controller is the larger S12S run on minimum settings and usually at no more than 50% throttle. So with my controller rated at 1000W drawing 200-300W is a greater reduction than that of a S6S controller similarly run. I'd be a bit careful here..

My canvas controller bag is a re-purposed ebike battery bag (thrift shop purchased) and has side vents. It sits on the rear rack mounting bars just in front of the panniers. It is ideal for hiding the rat nest of wires, which with my bottle battery, would be otherwise difficult to hide. My backup plan was to place the controller under the bag with the sides of the bag draping over it. This would mostly hide the controller while providing airflow to 50% of the surface, and would allow the rat-nest to be hidden in the bag. I ordreed two controllers in case I killed mine with heat, but I've been riding this way for a couple years and even through 35C (95F) heat without incident.

For rain (and it rains here nearly every day), I made a thick plastic battery cover with a rope strap to secure it over the battery and the downtube. I have a plastic tube sleeve (~12 cm diameter) that I can slip over the left brake and throttle to prevent shorting and an unplanned WOT event. I can still operate the brake and throttle through the plastic tube. These live in my panniers along with my harsh weather gear and take seconds to deploy. My SLCD3 has a permanent sandwich bag/packing tape constructed cover, which is open at the bottom to prevent pooling of water. A small piece of packing tape has protected the handlebar mounted PAS controls for years without need of replacement.

 

[motomech]

Must be time for a photo! Here's how things currently stand:



My goals for this build were for a lightweight/discrete commuting bike that could assist me to increase my average speed. Is it lightweight? Total added weight was 7kg, so I hesitate to give myself a pass there, although it doesn't feel heavy when I ride it so perhaps it is just a pass. Discrete? Well it doesn't scream ebike to me, however that frame bag is hard to miss! In my neck of the woods a rack and panniers would be much more discrete as I see them everywhere, however that involves putting the full weight of this conversion on the rear wheel. So perhaps it is just a pass here to. Impact on my average speed? Well I can now ride up most of my hills at 30kph, and easily cruise at 40kph on the flat using about 300-400 watts, so definitely a pass there!

Current issue: is my controller going to overheat? Here's how things look:



So yes the controller is in a bag with little opportunity to shed heat. I note molybdenum has been successful running his controller in a bag:

I hide my external controller in a small under-seat bag, which is a no-no but I'm only pulling 200-300W so it doesn't overheat even on the hottest days.

I do have a possible solution though: adding grommets to the sides of the bag inline with the controller, and an exit port at the back to create a wind tunnel affect when I'm riding to get some air moving past the controller. Something like three of these on each side of the controller, with a hole at the back to let the hot air out:



Realistically though it would not move a significant amount of air.

The alternate solution is to add a temperature sensor to side of the controller and just monitor the temperatures, dropping power if it ever overheats.

One like this could be put inside the bag which would sound an alarm if things started to overheat (for less than $10 bucks):
https://www.ebay.com/itm/Digital-Al...209193?hash=item2aa30dae29:g:w~gAAOSw2Ptap0P0

One like this could even be mounted on the handlebars to provide real-time monitoring:
https://www.ebay.com/itm/9Mini-Digi...852478&hash=item3d5d6eaa1f:g:2aQAAOSwHG9asPyZ

So my inclination is to just add a temperature monitoring probe, set an alarm, and throw it in the triangle bag. Thoughts?

People won't even make the connection that there is a battery in the bag(or care). Do you live somewhere where it even matters if the bike is super stealthy(Maybe you could fill out your profile?)? It only matters to me when I'm riding on a multi-use pathway and even then, keeping the speed down is more important than what the bike looks like if running a mini-motor.
A controller that big running such a little motor won't get hot. There is a ton of airspace inside the housing.
It's hard to know from the pic., but it appears that the battery weight is suspended from the bag's top straps. If that's the case, the straps will eventually pull the stitching loose. I bolted a 1 X 3 board (inside the bag) to the water bottle mounting bosses and the weight sits on that.

 

[ModeratelyFastF]

Thanks for the continued interest and replies.

I'm also running the large s12s controller (part of the reason things only barely fit in the bag!). I've now done my commute three times, most recently averaging 330watts at the motor. This pushed my average speed (over the whole commute inc stop signs, slowing down for pedestrians etc) to 30kph, with peak speeds on the flat of up to 42kph. This is with me pedalling at a comfortable level, but still putting in a fair amount of energy (150-200watts?). By comparison, before the conversion I was averaging 25kph over the whole commute.

At the end of the trip the controller has been warm, perhaps about body temperature? It certainly doesn't seem like it would overheat.

And honestly, running the bike at higher motor powers would take me to unsafe speeds I feel, so I'm not sure I need higher power levels.

For better or worse then I think I now have significantly over powered battery - the Bluetooth BMS em3ev uses tells me I used 27% of the battery... for the entire 32km return trip! I'm not sure how accurate it is, but the voltage drop in the battery I observed suggested significant energy was still available.

Regarding mounting the battery, the straps aren't taking the weight, just keeping it vertical. I would like to bolt something to the bottle cage mounts to hold the battery firmly, however their is just no spare space in the bag - even half a cm would be hard to accommodate.

Mounting the battery on the handle bars sounds intriguing. If the triangle bag ever fails I'd consider that over panniers.

 

[molybdenum]

It's great that you have it running well, and impressive how little battery you are using; I'm certainly surprised, and thought the number would be closer to 50%. Did you end up going with the 52v 721Wh em3ev battery? As for your seemingly overpowered battery, many dream of having 100 km range and it is only 4.3 kg. Charging to 90% instead of 100% and going no lower than 30% will see dramatic increases in battery life. Similarly, if you were able to make it two days without charging (and without over depleting), your battery would last twice as long! Having a larger battery reduces the amps per cell discharge rate, and keeps the battery cool and happy this has further benefits on longevity. I only see positives in the fact that your battery is only 27% depleted.

I'm also relieved to hear you went with the S12S; although being larger, it can take much more abuse. Although yours will likely be alright at those power levels, I'd definitely watch the heat on the hotter days. I imagine it can get pretty hot where you live. I live in a place which is cool and with nearly constant rain for most of the year. We only get a few 30+ C days a year towards the end of summer and daytime highs are typically between 6 C and 12 C for 7-8 months of the year.

 

[ModeratelyFastF]

Yes having excess battery capacity isn't really a problem, much better than the alternative anyway!

I have been charging to 90%, and since I only work one in two days (vs 5 in 7 for people doing 9-5), I think my battery is going to provide many years of service. It is the 52v 721wh battery by the way.

I also did order a cheap temperature sensor to mount to the controller, so that if I want to try out higher power settings I can do it safely.

So the only things left to do are to add some basic level of waterproofing. I live in a place where there's about a 30% chance of a shower on any given day, and although it wouldn't be heavy, it could be enough to cause a problem.

My current plan is to: put a plastic bag over the lcd, add another bag over the connectors in the bag, set up a drip loop on the motor cable (at the motor end and controller end), and some drip loops on the lcd cable. I'm running a pas sensor only (no throttle), so I'll also check if my pas sensor is waterproof.

 

[molybdenum]

The temperature sensor is a great idea, and I wonder if there is any way to get the probe inside the chassis and epoxied to a safe locale? I've tried and failed to kill my S12S, so they gotta be quite hardy at the power levels we're using.

You're lucky in a sense that your battery itself is quite water resistant - one less thing to waterproof. I'm guessing you have the horizontal style dropout? My vertical dropouts were easy for making a drip loop, as the cable exits pointing down and one zapstrap on the seatstay sealed the deal. I have a heavy duty ziplock baggie permanently in place over the SLCD3, cinched in place by an elastic band around the underside. I find I get about a year out of each baggie, and they are hardly noticeable.

My battery is getting kind of old, and has been through at least 500 charge cycles. It still works like new but it won't be long before I'll want to replace it. I have had my eye on the EM3EV 52v 721wh battery for a while now. I think it's a great battery and I'm toying with the idea of mounting it in the triangle or even directly under the handlebars in one of these and implementing a quick release so I can take it away by the handle like luggage.

Yes having excess battery capacity isn't really a problem, much better than the alternative anyway!

I have been charging to 90%, and since I only work one in two days (vs 5 in 7 for people doing 9-5), I think my battery is going to provide many years of service. It is the 52v 721wh battery by the way.

I also did order a cheap temperature sensor to mount to the controller, so that if I want to try out higher power settings I can do it safely.

So the only things left to do are to add some basic level of waterproofing. I live in a place where there's about a 30% chance of a shower on any given day, and although it wouldn't be heavy, it could be enough to cause a problem.

My current plan is to: put a plastic bag over the lcd, add another bag over the connectors in the bag, set up a drip loop on the motor cable (at the motor end and controller end), and some drip loops on the lcd cable. I'm running a pas sensor only (no throttle), so I'll also check if my pas sensor is waterproof.

 

[ModeratelyFastF]

This thing is tiny!



For now I just wedged the temperature probe between some of the fins on the controller, with the lcd mounted on the handlebars. I see this as a temporary setup, really just to give me a feeling about whether the controller has any chance of overheating under my typical usage - it's unlikely I'll ever want to use high powers as it's just too fast.

I'm really liking the em3ev 52v 721wh battery by the way, particular the Bluetooth BMS that tells you the exact state of the battery (voltage, balance status, charge percentage, energy remaining etc.).

Regarding waterproofing, I read people have used the lcd in the rain without any issue. I'll think I'll just take a chance there. I did manage to get a drip loop for the motor, but it does extend away from the axle a touch. I'm thinking of just having a big plastic bag to cover the controller/connectors etc in the bag, open at the bottom for airflow, big enough to prevent water coming down from above through the bag.

 

[ModeratelyFastF]

So after ~1500kms of reliable service I managed to damage the Q100C motor by pushing a bit too much power into it. Normally I would never run the motor at sustained powers in excess of 450watts, however I was running late and so ran it at ~900watts for 10 minutes or so. In hindsight this was a bad decision!

Not long after the motor started making significantly more noise, however it was still driving the wheel ok. As I was at work I then had to ride it home, and I found that about 80% of the time when the motor was active it was in the 'noisy' state, however sometimes it seemed to run like normal (i.e. quiet). I also found it would sometimes not kick in at all, however starting and stopping peddling a few times (it's a pedal assist only setup, no throttle) would see it kick in again. It sounds thoroughly sick, and even if it could in theory limp on like this, I wouldn't be able to put up with it in practice.

I managed to get the motor open in a vice, and although I didn't disassemble the whole thing, the gears all look ok (not obviously damaged anyway). My plan was to just buy a new motor and swap the insides into the existing housing (to save the cost/hassle of having a new wheel built), however I wanted to check with the brains trust here that my diagnosis that the current motor would probably never be the same is correct.

One other thing, I have the BMSBattery S12 controller in a bag. Is it possible it overheated and that it is the actual source of the problem?

Thanks all!

 

[motomech]

Since you are describing an "intermittent" prob., I would not suspect the prob. to be related to mechanical components like the gears.
Over the years, I have damaged two Cutes, one was a drop-out failure and one was a Hall sensor failure. I have also melted Hall/Phase wires and connectors. All of the Hall related prob.s were running the 328/big whl. combo, I have never had Hall related prob.s w/ either the 201 or the 260 motors. That's why for all but the most dedicated "roadie" types, I advise avoiding the 328/big whl. combo.
Early on in this build thread, I had thought about injecting myself to advise against the Q100/328/big whl. build, but could see I was greatly outnumbered and advocating the safe 201C motor w/ a top speed of 22-23 mph(on 52V), as opposed to the 328 w/ it's promise of mid to high 20's mph to be a hard sell anyway.
The idea that either using a small (low power) controller or limiting a more powerful controller to control heat and somehow protect the Hall and phase systems is a false safe-guard. Although a "too hot to touch" controller is something to be avoided, the high-speed motor's demand to pull max Amps in high-load/low RPM situations can cause damage long before the controller becomes a heater.
At this point, I would recommend a Hall system integerty test as out-lined at the Grin site or in the archives here. Perhaps wiring or connectors have melted/fused(the kit supplied "bullet" connectors on the phase wires are notorious for this) and the repair would fairly easy((but would not address the root cause). Or perhaps one or more of the Hall sensores may be damanged. Although Halls for the Cute are readily available, their "stand-off" mounting position requires a jig to get them positioned exactly right and at that point, it's probably more time-efficient to just buy another motor.
I could be wrong about all this, but what the PO is describing sounds a lot like a hard road I've been down before.

 

[ModeratelyFastF]

Thanks for the reply motomech.

I always knew it would be a risk to run the 328rpm motor in a 700cc wheel, however the trigger for my problems was nearly doubling the highest sustained power I'd ever run it at.

I checked the wiring (I assume you meant between the controller and the motor) and couldn't see any signs of damage/heat, so I'm thinking it is the motor itself.

As I'm time poor these days I think I will buy a new motor or two to swap into the wheel (the 328rpm job again) if the repair isn't straightforward, but strictly limit input power to 500watts or so. Even if I only get 12 months out of each one, that is still saving me money over getting public transport to work.

 

[styczoo]

Hi!

I'm new here! My name is Marcin and I come from Krakow/Poland/Europe.

I'm going to build my first e-bike, a commuter bike based on Radon Skill 7.0. After long analysis I've chosen q100c@201 rpm. I've got some 10% hills which is the steepest sections go up to 20%. My commute is 26 - 30 km both ways. For analysis I've set the wheel size to 424 mm to mimic the 201rpm on 328. https://www.ebikes.ca/tools/simulator.html?bopen=false&motor=MCUTE36V_328&batt=cust_48_0.2_6&wheel=16.69i&mass=95&hp=150&k=1&autothrot=false&throt=65&black=grade&blue=Lbs&cont=cust_18_70_0.03_A&frame=road&grade=0
I was thinking to use battery: 13s2p, 13s3p, 14s2p or 14s3p. 2p is obviously more stealth and lighter but is it enough for my needs? The batteries sony-us18650vtc6 should allow such amperes.
I haven't chosen controller yet. I'm going to build a carbon/glass box for the battery and controller - I already have some experience in laminating.

Any advises on the build are welcome!

 

[ScooterMan101]

You are going to be sorry if you buy a Q100c when going up a hill 10% , and you will kill it on a hill of 20%.

You want a Mac Rear hub motor . ( or any other motor that has the same spec's as the Mac )
Mac 10t or Mac 12 t Rear hub motor, freewheel or cassette version depending on how many speeds your rear shifter and rear derailleur has.

The new Mac motor when paired with the right controller and a Cycle Analyst 3.0-3.2 will have a thermal rollback feature to shut off the controller or limit the power when it senses the motor getting too hot. this is important on a 20 % grade hill.

A good mid-drive is another option for you.

Hi!

I'm new here! My name is Marcin and I come from Krakow/Poland/Europe.

I'm going to build my first e-bike, a commuter bike based on Radon Skill 7.0. After long analysis I've chosen q100c@201 rpm. I've got some 10% hills which is the steepest sections go up to 20%. My commute is 26 - 30 km both ways. For analysis I've set the wheel size to 424 mm to mimic the 201rpm on 328. https://www.ebikes.ca/tools/simulator.html?bopen=false&motor=MCUTE36V_328&batt=cust_48_0.2_6&wheel=16.69i&mass=95&hp=150&k=1&autothrot=false&throt=65&black=grade&blue=Lbs&cont=cust_18_70_0.03_A&frame=road&grade=0
I was thinking to use battery: 13s2p, 13s3p, 14s2p or 14s3p. 2p is obviously more stealth and lighter but is it enough for my needs? The batteries sony-us18650vtc6 should allow such amperes.
I haven't chosen controller yet. I'm going to build a carbon/glass box for the battery and controller - I already have some experience in laminating.

Any advises on the build are welcome!