Cuda-E - 4000 watt Shumaker drive upgrade

[www.recumbents.com]

I have been thinking about lights. Bright lights. Lights that I don't have to replace batteries in. Matt told me about the CC BECs. They handle up to 12S of LiPo and have an adjustable voltage output. This is perfect. Here's what I have in mind:



I have built LED lights before, and it was fun but it takes a long time to build the housing.
http://www.recumbents.com/wisil/led_light/default.htm

Does anyone have a better solution?

-Warren.

[www.recumbents.com]

Hey all,

Today I learned something new about RC e-bike systems. If you connect up all the wires except the throttle, including power, you can accelerate/decelerate the motor just by getting close to, then touching the casing on the throttle wires.

-Warren.

[AussieJester]

Does anyone have a better solution?

-Warren.

Edward Lyen sells a dc-dc converter ~25 bucks input upto 70v output 15v IIRC (have one but not used it yet)
I saw a thread yesterday someone running a magic shine light from it...

KiM

[D-Man]

Hey all,

Today I learned something new about RC e-bike systems. If you connect up all the wires except the throttle, including power, you can accelerate/decelerate the motor just by getting close to, then touching the casing on the throttle wires.

-Warren.

Do you have a kill switch? I'd have one nearby. I don't trust those rc speed controllers yet. They seem to have a mind of their own. Nice build by the way.

[recumpence]

Hey all,

Today I learned something new about RC e-bike systems. If you connect up all the wires except the throttle, including power, you can accelerate/decelerate the motor just by getting close to, then touching the casing on the throttle wires.

-Warren.

Do you have a kill switch? I'd have one nearby. I don't trust those rc speed controllers yet. They seem to have a mind of their own. Nice build by the way.

You will trust them once you use them for a while. The only glitches I have ever had with throttle was related to the use of radio control receivers, not the controller itself.

Matt

[www.recumbents.com]

I just bought one of Lyen's DC to DC converters. 3A, adjustable with a trim pot and under $20. Can't go wrong!

I can't think of any reason why I wouldn't connect the throttle cable before connecting the power under normal circumstances, but I thought I'd throw that oddity out there as an FYI. I do have a switch of sorts - the PowerPole connector loop on the outside of the battery box. I moved the fuse inside the box so now it's just a loop of wire. Like Matt said, the RC system should be very reliable, but since this is my first one I may add a pull cord to it so I can yank the power in an emergency.

This weekend I will be mounting the battery pack to the bike, probably with a bracket made of bent and riveted aluminum strap.

BTW, I saw something somewhere about using a 555 timer to build an ESC controller circuit. I like 555 timers. Has anyone tried that here on the Sphere?

-Warren.

[recumpence]

Warren,

There is no reason to ever unplug the throttle. The only thing you need to do is connect or disconnect the battery.

Matt

[www.recumbents.com]

I put together an RC tutorial. Hopefully it will help people to build up their own RC systems. Please let me know if I missed anything.

http://www.recumbents.com/wisil/e-bent/ ... torial.htm

I built up the aluminum brackets to hold the battery on the bike and it's solid now, but kind of fugly. I also rearranged the connectors on the battery box for the third time.

-Warren.

[katou]

This is a great build, I'm so glad that I caught it! Super clean, and as Matt says, so nice to see another RC build running! It gives me hope that I will one day have my 8150 reborn in a similar setup!

Katou

[SoSauty]

How'd this post double?

[SoSauty]

Wow Warren,

Your tutorial is near priceless and your diagrams worth a 1000 words each! You didn't miss any points on your outline did ya Clear diagrams along with concise explanations, have you, or do you teach elementary kids? Only a select few are as insightful as you, to producing a tutorial. The only little criticism I can come up with is those 3 little signal wires from the servo to the ESC. Think it's brown to black, red to red, and white to orange. Your wires are not the same color as mine or the diagram doesn't show that. Did I say, "Outstanding tutorial"

[Byte]

I put together an RC tutorial. Hopefully it will help people to build up their own RC systems. Please let me know if I missed anything.

http://www.recumbents.com/wisil/e-bent/ ... torial.htm

I built up the aluminum brackets to hold the battery on the bike and it's solid now, but kind of fugly. I also rearranged the connectors on the battery box for the third time.

-Warren.

Noooo! Oh my god! You spelled "Plettenberg" wrong! What a shame (Spelled it as "Plettenburg") Hehe, anyway, that manual looks fantastic! This link should be in some kind of sticky. Good work!

[jmygann]

I put together an RC tutorial. Hopefully it will help people to build up their own RC systems. Please let me know if I missed anything.

http://www.recumbents.com/wisil/e-bent/ ... torial.htm

.

This is great ... much thanks

[www.recumbents.com]

Happy to help.

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.

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

-Warren.

[www.recumbents.com]

I'm not happy with the way the aluminum strap battery mount turned out. It's too cage-like.

I receive the Avid BB7 203mm disk brake, and bolted it on with a single 5mm bolt to check clearance. The stock bolts were not long enough to make through the chainring adapter, 1/8" spacer, and the disk brake.

As seen here, the huge brake entirely hides the chainring. The brake caliper is just resting there. I'll need to make a special bracket and braze it onto the rear dropouts.



Here's the top view showing the tight tolerances and spacer. The brake rotor definitely clears the frame, but may rub on the extra wide BMX chain. I will probably space the chainring in with some thin chainring shims to buy the extra clearance there.



-Warren.

[E-racer]

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.

[www.recumbents.com]

I used one of Matt Shumaker's sprocket adapters, a standard 48T chainring, a 1/8" shim plate and a standard Avid 203mm rotor.

-Warren.

[katou]

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]

Great idea Katou. Can anybody point me to the information about how to choose a motor? I'm sure there are threads about that here. I'll try to distill it and add it to the tutorial.

As for noise level, check out the couple videos I posted previously.

-Warren.

[Hillhater]

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.

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

-Warren.

A common fallacy. Mine works fine with a Hall effect throttle !

[katou]

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.

[www.recumbents.com]

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/ ... ulator.asp

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



-Warren.

[katou]

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

[katou]

The general number mentioned I've seen is about 70% of rated RPM under load.

Katou

[www.recumbents.com]

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/ ... ulator.asp

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

-Warren.