Cuda-E - 4000 watt Shumaker drive upgrade

Your sproket/rotor looks great!Ive been considering doing something similar on my bike. My original plan is to go with a combined Sprotor. Using some a custom caliper bracket to incorporate some idlers to get the chain around the caliper. Seeing your setup may have just changed my mind... hmmm decisions... This is great because you can run store bought rotors, and I wouldn't have to buy $50 in idlers/bearings/alum stock + machine time! Down side is that sprocket to rotor adapter is a little bit more complicated to make. What bolt pattern did you chose for the sprocket? I would be torn between the standard go-kart 4 bolt pattern for #35 chain or the Goped pattern for #25 chain. You've got me thinking because I have a Hayes Sole single piston caliper that is super shallow on the back side.
 
Stuff to add:

How to choose a Kv for your motor (ie which one)
video showing how loud they are (common question) with reference sounds in video to show relative loudness (maybe hair dryer, small car engine running, normal conversation, wind noise at 30 km/h)

Just a couple of ideas,

YMMV,

Katou
 
www.recumbents.com said:
I updated the Pletty spelling so as not to offend those Plettenberg fans, added a note about the ESC throttle wire colors and that little plug that can be plugged in more than one way, and noted that you need a 5K resistive throttle to retrofit to the servo controller, not a hall effect one. :D

All important stuff to know if you don't know, k'know?

-Warren.
Click to expand...

A common fallacy. Mine works fine with a Hall effect throttle ! :wink:
 
Well, I posted the only bit that I think is useful, that I ever read. That's because no one has ever explained, and my half-assed explanation was therefore state of the art. It is pretty much guaranteed that there are many here who could do a massively better job just falling off their chair.

The videos should be part of your page, not here is my point. And reference noises would be a nice addition. I did of course watch your earlier videos, thanks for posting them.

I'll go try to find that KV thingy I wrote.

Katou

EDIT: couldn't find it. If someone can do a good job, now would be a good time to jump in.
 
Ok, I did some reading, and this is what I'm going to add to the tutorial unless I am told that I'm not understanding something correctly.

There are several parameters to look at when choosing an RC motor for your e-bike application. The first is, inrunner or outrunner? With inrunner motors the shaft rotates. This is good for driving chains or belts. With outrunner motors the outside shell rotates. This is good for direct friction to tire drive applications.

KV - RC Motors are AC brushless motors and are rated by their KV. KV is the relationship between voltage and motor speed (rpms per volt. Multiply the motor KV times the battery voltage to find the maximum motor RPM. For instance a motor with a KV of 100 would run at 5000 RPMs at 50V.

E-bike RC motors run at lower than 10,000 RPM with no load. Higher motor speeds than that cause the speed reduction gearing to becomes impractical. This means with a 33V battery pack you will want a KV of 250 or lower, or with a 44V battery pack you will want a KV of 225 or lower. The Astroflight 8120-5T is a 225KV motor. 5T refers to five of turns per coil in the motor. In general, fewer turns equals higher RPM.

Next you will need to determine how much power you need. RC motors are rated in watts. It takes around 2000 watts to get up hills at a decent speed and to go over 20 MPH into a stiff headwind, so that should be the minimum to consider. Anything over 5000 watts is a monster motor and will require a very powerful battery and stronger than standard bicycle drivetrain components.

Calculator V.09 http://www.recumbents.com/wisil/e-bent/rc_drive/rc_drive_calculator.asp

How do I calculate what the maximum loaded RPM is given the motor KV * volts?



-Warren.
 
Recently, Recumpence posted that he had re-geared one of this trikes for a higher ratio in order to run the motor at a higher rpm. He's a pretty smart cookie, so when he did that, I thought long and hard about why he made the change. I see a few reasons to do this:

The higher rpm, the higher the power, assuming other things stay the same.

The higher reduction ratio means that the motor is running faster, even at low speed, which eases the controller's job. This helps to avoid lugging.

Motors run more efficiently when they are running at max rpm

These things suggest that perhaps, a Kv should be chosen that will hit Max RPM for that motor at the specified voltage, and that the gear-down be done as necessary.

This philosophy would tend to increase the Kv people would pick, complexify drivetrains, and increase noise all other things equal.

Personally, I think this is the way to go, and it is the way that I chose the wind for my 8150. I noted the max voltage that the CC HV series could handle, then got the Kv that would hit max rpm (12,000) at the target 50v.

Katou
 
Hi Katou,

Hmm, yes. Saying that 10,000RPM is the max RPM is a bit limiting. I'll try to figure out a good way to say that higher max RPMs allow better performance off the line but gearing may be more difficult, and incorporate some of what you noted. Good stuff. I'm not the expert so I don't want to write a book on choosing an RC motor, just to give some guidelines.

70% does look very close to the actual numbers I am seeing, thanks.

Here's the speed calculator. It's not pretty yet, but it works. http://www.recumbents.com/wisil/e-bent/rc_drive/rc_drive_calculator.asp

I'll add it and the other video in the garage with the noisy RC drive screaming away and waking up the neighbors. :lol:

-Warren.
 
Don't underestimate what you are doing. This will become a major resource for anyone going down this road, myself included.

I have a good comfort level with math, so if you want any worked examples using formulae or something like that, let me know. I've always believed that understanding the formulae and following the math leads to the best understanding. Along with a few fudge factors of course.

You may find that the "added complexity" necessary for the higher reductions is not so complex at all.

Recumpence has shown how a 2-stage reduction can be made fairly easily, and you always get another reduction to the rear wheel. Especially important now that really, really, big rear sprockets are becoming more available.

No one has been able to get a reliable planetary reduction though. Not that I've seen anyway.

Katou
 
I updated the choosing an RC motor section of the tutorial to expand it a bit and allow for higher RPM, and updated the RC drivetrain calculator to allow for a 3rd stage.

Tutorial - http://www.recumbents.com/wisil/e-bent/rc_drive/tutorial.htm
Calculator - http://www.recumbents.com/wisil/e-bent/rc_drive/rc_drive_calculator.asp

-Warren.
 
Astro motors are good up to 30,000 RPM. However, most reduction types (toothed belts and chain) start becoming very inefficient above 15k. So, 15k RPM is the sweet spot for power.

I am in the process of looking into a 4 turn 3210 that will run roughly 15k RPM under load to see just how much power can be had with enough reduction. :)

Matt
 
I designed my drivetrain (as yet unbuilt) around the figure of 12,000 rpm, at 50v (limit of HV series of CC controllers).

Bummer to find out I should have aimed a bit higher! Oh well, I can use a modified Lyen controller as soon as the sensored kits are ready for the astro to run higher voltage, but need a bigger battery then.... Yikes.

Maybe I'll just keep going down the road I've planned so far.

Katou

EDIT: I just re-read your tutorial, and I noticed that the link to Matt's V3 drive is missing? If I wanted to follow in your footsteps, I'd want to have access to all of your suppliers. Just an idea.
 
I tried four separate bike bags to mount the battery box. Some were too big, some were too small, and some were odd shaped.
So I spent a whole bunch of hours making this spiffy aluminum cage that bolts to my battery shelf. The battery slides in and out from the side.

Img_0145.jpg


Unfortunately, it's really ugly.

Next I decided that if I mounted some feet to the bottom of the case that would keep it from shifting around on the rack, then I could just strap it down with some Velcro.

Img_0146.jpg


Except then I would have to drill more holes in the case and the screw heads may abrade the battery packs.

My final thought was to use a chunk of self adhesive Zote foam on the bottom of the box, and cut grooves in it to fit the cross tubes on the rack. That holds it nice and firm when strapped down with velcro, plus it will be easy to remove.

Img_0157.jpg


I still need to hide the wires a bit. I thinks I will build a black Coroplast cover for the ESC and wires that will let the air flow through.

Now all I need is a day when dry roads and free time coincide. I suspect that will probably be in April...

My next task is to figure out how to make the tppacks.com charge controller I assembled work with a single 48V Meanwell PSU.

-Warren.
 
Very clean, and I like the thinking about the bottom of the box mechanically locking into the rack! Very "less is more" thinking.

It continues to look nice and clean, I look forward to the next update!

Have you considered a cover for the Shumaker drive? Most don't around here, but seeing as you're going to do a cover for the ESC...


Katou
 
Katou: I have a Coroplast panel I'm working on that will fit in the space between the upper and lower seat stays. Nothing fancy. I'm still contemplating whether or not I want to cover it.

Matt: You betcha. It would also be fun to have a Chicago area e-bike get together sometime this summer.

I soldered up the Lyen DC to DC converter with aAnderson connectors on one end and two connectors for the MagicShine lights. I used the screw adjustment on the little blue potentiometer you can see in this picture to set the output voltage to 8.4 volts because that's the voltage these lights like to see. It seemed to work fine for the couple minutes I was running the MagicShine lights. Here's the DC to DC converter, some wires, and the headlight. I'll cover the bare wires and mount it to the battery pack with some velcro.

Img_0158.jpg


It's very cool to have that bright a front/rear LED light system connected to the main battery pack for under $100.


-Warren.
 
Found that kv choosing thread I mentioned earlier.

http://endless-sphere.com/forums/viewtopic.php?f=28&t=14238

Katou
 
It's finally starting to get a little warm out, and it's stopped raining for a couple hours. Nobody was breathing down my neck, so I took the Cuda-E for the first longish ride. I only went 7 miles, but that was enough to test it's performance.

Top speed was about 27.5 MPH. That means the motor is spinning at 6000 RPM at full throttle. It also means that I need to change the gearing a bit. Going from the current 48T rear chainring to a 44T ring will get it up to my target speed of 30 MPH.

Wattage to cruise at 27MPH was only about 400 watts, which is less than half of what my BMC powered MTB uses. That means I may actually be able to make the 14 mile trip to and from work on one charge of the battery. I guess that shouldn't amaze me, the bike had a 24V "450 watt" Curry brushed motor on it in it's previous incarnation that also went 30 MPH (although it got there a whole lot more slowly). It used a 20Ah - 24V LiFePo4 battery, which stored the same amount of power as the 10Ah, 44V LiPo battery I'm using now, and got me to and from work on one charge (barely).

The one thing I wish it would do that it doesn't do is take off quickly from a dead stop. That would really help getting across the road in busy traffic. Does that mean I need a gearbox like the Thudster 2 speed unit or just a bigger motor? :shock:


-Warren.
 
How do you find the sound of the CR motor and drive? In the video it sounded very high pitched and quite noisy. Is it a lot quieter under load?
I know some camera microphone tent to exaggerate high pitched noises.

Kurt.
 
Warren,

There are a few ways to have faster take-off. One is a bigger motor (more startup torque). One is a higher RPM motor with lower gearing. That gives more armature pulses per wheel revolution, thus giving more torque at startup. All you really need is one pedal stroke, then hit the throttle. You will get the hang of it. :)

If you wanted to go with a bigger motor, you will have way more power. Your controller is good for twice the load you are giving it. However, you really do not NEED a bigger motor. But, then again, who NEEDS what we are building? :mrgreen:

Your motor was chosen for your required top speed and super high efficiency. If you gear it too tall, you will pass that efficiency point. I believe your motor is highly efficient up to about 600 or 700 watts before you begin dropping a touch of efficiency. So, you are good there. You can gear up and be fine up to close to 35 mph or so would be my guess. If you go with a hotter motor, your efficiency may suffer a touch at lower power levels, but peak at higher power levels.

I will give you a call and we can discuss it.

Matt


Oh, it is about time you posted some serious hardware on your Avatar! :twisted:
 
Hi Kurt,

The sound in the video is pretty accurate. This is not a stealthy motor. Not loud by any means, but on a quiet street people can hear you coming and going. I don't think you could hear it in a car with the widows closed unless you are right beside them. It almost sounds like one of those crotch rockets that you can hear from miles away as it winds out to 12,000 RPM, but much quieter.

I have a couple e-bikes and this is the loudest but it doesn't bother me. It's sort of like riding in a high performance car. A bit noisier than your family e-cruiser, a little rough around the edges, but massive fun.

Matt: This system works great as is, but as you know we are always looking for more. Ha, this is my 3rd e-bike in 5 years. We can start planning the drivetrain for my next project, the quasi-bent e-chopper. Unlike my previous e-bikes, this one will not be practical. :twisted:

Latest concept:
chopper9a_sm.png


Oh, and I do have an idea for a e-bike related avatar pic, but I need to take some pictures first and it will need some photo-chop work.

-Warren.
 
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