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Old 06-27-2011, 11:19 AM   #1
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Default The e-bike thread.

Iíve been casting about a lot, trying to figure out the next project. Frankly, Iíve been in a hell of a rut lately. Canít even muster up the enthusiasm to assemble this NB engine Iíve had sitting on the shelf for over a year. And then a few weeks ago, out of the clear blue as if to King Arthur in Monty Python and the Holy Grail, it hit me: I shall build a hybrid.

A very lightweight, ethanol-fueled, plugin hybrid. **** gasoline. And **** E85, too. This is going to be a zero-fossil-fuel vehicle. Fortunately, ethanol is fairly easy to come by around here. Itís not particularly cheap compared to gasoline, but this is a matter of principle. (And I donít plan on burning large quantities of it.)

At the same time, I want to keep the design as simple as possible. Regenerative braking will probably not be a part of the initial build, for instance. And itís going to be a straight parallel configuration, keeping the ďconventionalĒ drivetrain as conventional as practical. Since this is going to be purely a short-range commuter vehicle and not a high-power thrill ride, I think I can keep the battery expense and system complexity to a minimum by adopting a rather different philosophy from most other hybrid designs, be they commercial or homebrew.

The conventional engine is actually going to be the primary power source, but itís going to be extremely small; sized to provide sufficient power for straight-line cruise when operating at peak output, but little else. The electric motor will act as an on-demand booster, to provide supplementary torque for acceleration and hill-climbing.

I am thinking about going slightly hi-tech on the electric motor. Most homebrew jobs I've seen used brushed DC motors. Why is this? Well, they're cheap for one. And they're sort of a known commodity. Easy to control with simple PWM. On the other hand, you don't exactly see a lot of OEMs using them- at last count, the number was zero. They're heavy, inefficient, and, well, they have brushes. Fine for Nikola Tesla, but not my cup of tea. Brushless DC motors (the kind that power RC airplanes and the fans inside your PC), which are really just AC motors with permanent magnets and hall sensors, are starting to become available in reasonable power outputs, and there are some off-the-shelf controllers now capable of handling them without much fuss.

Iíve been reading a fair bit about Lithium Manganese battery chemistry recently. LiMn cells donít provide quite the same energy density as some of the more exotic Li-(x) technologies, but theyíre still a lot lighter than lead-acid, yield excellent cycle life and are a relatively safe design, tending not to fail explosively if subjected to abuse.

Lightness is the key. Lightness, and a low aerodynamic profile. The finished product should make Robís Red Beast look like a Cadillac Escalade with a barn sitting on top of it by comparison, even with the batteries in place. Iím leaning in the direction of a very minimalist tube-frame chassis, though I donít want to sink gobs of money into the mechanicals. There wonít be any inboard pushrod shocks or fancy billet parts here.

Decisions...
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Old 06-27-2011, 11:31 AM   #2
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So I take it your EJ powered ariel atom looking thing went down the toilet?
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Old 06-27-2011, 11:33 AM   #3
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Sounds like fun. You could use the front and rear subframe assemblies from a miata to keep cost low and suspension design simple.
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Old 06-27-2011, 11:36 AM   #4
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So I take it your EJ powered ariel atom looking thing went down the toilet?
This.

I am wondering the same.
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Old 06-27-2011, 11:43 AM   #5
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^Likewise.

C
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Old 06-27-2011, 12:03 PM   #6
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Do you plan on using an existing chassis, or do making a tube chassis? The way I read your post it sounded like you were going to buy a beater, and pull the engine. But with the suggestion of using a miata subframe made me think otherwise.
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Old 06-27-2011, 12:18 PM   #7
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Joe, take a look at some of the e-bike builds on the endless-sphere website. particularly those by "liveforphysics" like this:
http://endless-sphere.com/forums/vie...hp?f=28&t=8347

I almost wonder if you can just use 15 or 20 of those brushless, cheap motors for your application.

also, you have to add the feature that starts and stops the gas motor at stop lights. heck it's standard on the new M3. And I showed the calcs in another thread that show you are wasting gas--sorry, Ethanol--after somewhere between 3 and 10 seconds. If you could get the electric motor to essentially "push start" the gas engine, it'd be pretty win.
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Old 06-27-2011, 12:21 PM   #8
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also, you have to add the feature that starts and stops the gas motor at stop lights. heck it's standard on the new M3. And I showed the calcs in another thread that show you are wasting gas--sorry, Ethanol--after somewhere between 3 and 10 seconds. If you could get the electric motor to essentially "push start" the gas engine, it'd be pretty win.
So does Mazda on the newer gas engines, but they don't use an electric motor to start. They stop the engine at a specific crank angle with a charged cylinder, and relight it with a spark event. Very cool.
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Old 06-27-2011, 12:39 PM   #9
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http://www.locostusa.com/

This might help with some of the chassis building.
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Old 06-27-2011, 12:42 PM   #10
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Quote:
Originally Posted by 18psi View Post
So I take it your EJ powered ariel atom looking thing went down the toilet?
I kind of lost interest in it. I know, this is probably a sign of insanity. The motor and transmission are still taking up space at the fab shop in a crate, I just can't work up the enthusiasm to give a **** about it. I have an itch to do something different right now. Maybe howling insanity will be part of a later build build.



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Sounds like fun. You could use the front and rear subframe assemblies from a miata to keep cost low and suspension design simple.
Collectively, the front and rear subframes of a Miata weigh rather more than what I'm targeting for the whole chassis.



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Joe, take a look at some of the e-bike builds on the endless-sphere website.
Funny that you mention this- I've been spending a fair bit of time over there. They've been doing some pretty neat stuff recently with computerized advance of coil timing on the BLDC motors. For some reason, most of the controller makers haven't figured this out yet, but just like with spark-ignition engines, these motors like to see more coil advance at higher RPM. They're seeing increases in motor current and torque upwards of 100% simply by optimizing the advance at high RPMs.

http://endless-sphere.com/forums/vie...45f8f64d83ce48



Quote:
I almost wonder if you can just use 15 or 20 of those brushless, cheap motors for your application.
That would mean 15 or 20 separate controllers, which is getting on towards silly. Unfortunately, you can't parallel those motors- each one needs its own controller, as it's a closed-loop system. The controller sequences the coils in response to feedback from the hall sensors.
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Old 06-27-2011, 12:48 PM   #11
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Collectively, the front and rear subframes of a Miata weigh rather more than what I'm targeting for the whole chassis.

Damn. I was hoping you'd make a cool hybrid and pioneer the much needed low locost kit using stock subframes, a-arms, and steering. Oh well.
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Old 06-27-2011, 01:36 PM   #12
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Quote:
Originally Posted by Joe Perez View Post
Funny that you mention this- I've been spending a fair bit of time over there. They've been doing some pretty neat stuff recently with computerized advance of coil timing on the BLDC motors. For some reason, most of the controller makers haven't figured this out yet, but just like with spark-ignition engines, these motors like to see more coil advance at higher RPM. They're seeing increases in motor current and torque upwards of 100% simply by optimizing the advance at high RPMs.

http://endless-sphere.com/forums/vie...45f8f64d83ce48



That would mean 15 or 20 separate controllers, which is getting on towards silly. Unfortunately, you can't parallel those motors- each one needs its own controller, as it's a closed-loop system. The controller sequences the coils in response to feedback from the hall sensors.
that site must just come up when you search for this stuff. the bikes were pretty cool so I read through some threads but didn't delve too deep.

So why is multiple motor-controller stuff silly? Maybe you can build your own "megashock" that controls each motor and stuff a dozen together to control many motors.
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Old 06-27-2011, 01:41 PM   #13
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Joe, if it will help any, I have both the standard and plus Locost frames drawn up in 3D (Solidworks). Simple tube design, and proven to work. Probably not as light as you'd envisioned, but it's a starting point.
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Old 06-27-2011, 01:58 PM   #14
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How about a small aerodynamic FWD vehicle, liek for instance a CRX or other older Civic hatch, with a D15z1 or D16b2 (should already be capable of 40+ mpg), then build an electric drivetrain in the rear.

I wonder what would be the lightest option for the electric stuff in the rear. Possibly some whimpy live axle, but then you have to have a driveshaft because you want the motor to be sprung. So I would think IRS would be the way to go.
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Old 06-27-2011, 03:21 PM   #15
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I'm sad. I still hoped you would end up with a FM Westie.

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I know, this is probably a sign of insanity. I have an itch to do something different right now. Maybe howling insanity will be part of a later build build.
It's been awhile since I've seen you. You aren't walking around in a lab coat with your hair mussed up muttering about 1.21 gigawatts these days are you?



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Collectively, the front and rear subframes of a Miata weigh rather more than what I'm targeting for the whole chassis.
So...you are thinking of building something like a pair of Huffys welded together side by side with you sitting down low between them?
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Old 06-27-2011, 04:22 PM   #16
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A very lightweight, ethanol-fueled, plugin hybrid. **** gasoline. And **** E85, too. This is going to be a zero-fossil-fuel vehicle. Fortunately, ethanol is fairly easy to come by around here. It’s not particularly cheap compared to gasoline, but this is a matter of principle. (And I don’t plan on burning large quantities of it.)
Electricity from your plug is probably largely generated by coal, si o no?

Last edited by Scrappy Jack; 06-27-2011 at 04:35 PM. Reason: Italics don't add emphasis when the whole quote is italicized.
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Old 06-27-2011, 04:54 PM   #17
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Electricity from your plug is probably largely generated by coal, si o no?
At least its doing it significantly more efficiently
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Old 06-27-2011, 05:36 PM   #18
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Electricity from your plug is probably largely generated by coal, si o no?
*waits for Joe's personal wind turbine thread"
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Old 06-27-2011, 07:15 PM   #19
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I have heard that fresh orange rinds contain large quantities of hydrogen, fwiw.
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Old 06-28-2011, 12:38 AM   #20
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Quote:
Originally Posted by Full_Tilt_Boogie View Post
I wonder what would be the lightest option for the electric stuff in the rear. Possibly some whimpy live axle, but then you have to have a driveshaft because you want the motor to be sprung.
The motor(s) need not be sprung, particularly if small and lightweight.


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I'm sad. I still hoped you would end up with a FM Westie.
Well, I have to admit that after doing a hell of a lot of research and reading, California's motor vehicle registration rules have finally gotten to me.

The reality of the situation is that there are only five hundred SB100 certificates issued per year in the whole state, all of which are gone within the first few minutes of the first business day each year, and there are a hell of a lot of hoops to jump through to get it all right. Hinging an entire build on the SPCNS program, with the hope that everything will go just swimmingly and not a single paperwork snafu will occur is just too great a risk. Having to sit and stare at such a vehicle sitting in the garage for a whole year because some Selma down at the DMV took 30 seconds too long to key in a form would just destroy my spirit.

As much as I hear people decry CA's motor vehicle laws, I usually don't find them all that bad. But this is one area where the law really is completely fucked up. You can't even do a pure EV conversion of an automobile without an SB100 certificate. That's right- you could take a 1982 Chevy Caprice, rip out the engine and fuel tank and replace them with an electric motor and a set of batteries, and you will still fail smog, not because of your completely nonexistant tailpipe emissions, but because you tampered with every single emissions control device on the vehicle.

On the other hand, vehicles with fewer than four wheels are not automobiles from CARB's point of view.



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It's been awhile since I've seen you. You aren't walking around in a lab coat with your hair mussed up muttering about 1.21 gigawatts these days are you?
I could probably use a haircut.

But no, since moving back out here it's been very much business as usual. Spending a fair bit of time on the road (just got back from 2 weeks in Birmingham, 2 weeks in NYC before that), and the rest of the time in the lab. Fortunately we don't have labcoats- shorts and Hawaiian shirts are the typical dress code.



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So...you are thinking of building something like a pair of Huffys welded together side by side with you sitting down low between them?
We're sort of getting into the general neighborhood.



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Electricity from your plug is probably largely generated by coal, si o no?
Not around here.

The latest data I have from SDG&E is for 2009, where 7% of our electricity was generated from coal, 31% from nuclear, hydro, wind, and other carbon-neutral sources, and 62% from natural gas. So while we're definitely still fossil-fuel dependent, CA probably has just about the "cleanest" electrical supply around.

It'll be interesting to see how that changes when the Blythe plant starts to come online in 2013. At 1 GWe, it is by far the largest solar power plant ever constructed.

All told, there's a total of 4.3 GWe worth of parabolic trough solar capacity currently on the CSP docket, with the Beacon and Abengoa projects (250 MWe each) already approved in addition to Blythe. Ivanpah is also supposed to come online in 2013, with a capacity of 392 MWe. (It was supposed to be 440 MWe, except those damn, good-for-nothing tortoises decided to lay an egg right at the extreme northeast end of the field.)



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Originally Posted by icantthink4155 View Post
*waits for Joe's personal wind turbine thread"
I live in an apartment building. I don't think that the management would appreciate my hoisting a turbine.







Oh, and, how exactly does one liberate hydrogen from orange rinds?
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