Paul & Sabrina's cheap DIY 144v motor controller

[bennelson]

Originally Posted by Christ

what do you call that knot? LOL.

It's a square knot with an additional loop knot on the end to prevent fraying and some fancy wire!

Try learning that in boyscouts!

True, the car probably has about the same amount of power right now as it did as an ICE, BUT! And it's a big BUT.

100% torque at 0 RPM
No reving the engine first
No gas needed.

I am going to make it into a sleeper and race for pinks.

[esoneson]

EV Version of "American Graffiti"

Starring Ben Nelson as "Spark"

"Gas, gas.......we don't need no stinking gas!" Oops, wrong movie.

Way to go Ben!!!!!!!!

Eric

[GrahamMc]

Nice Work with the Geo. Did you guys know Solid Works is having free 90 day trials of their modeling software? It is not bad, and a free download. Sort of fun and has tutorials, so if you wanted to model something up and could learn to use it in 90 days it would be free to do the CAD stuff. Here is where the download is:

SolidWorks :: SolidWorks Engineering Stimulus Package

On another note, I got a 10% paycut today and am going to have to put the controller on hold for at least a while. I will be paying close attention and would still love to photograph one for posterity and open sorcerers (just made that up) everywhere so don't count me out just yet.

[taffy]

I actually learnt solidworks as part of my uni degree. I liked it alot more then CATIA or Autocad.

I am moving closer to making one of these myself. I can get most of the parts locally. But making up a cad model is not such a bad idea... but that will happen at as i am still building the rest of the car, a website and trying to keep SWMBO happy.

[bennelson]

Hey Paul,

I believe the controller is making a bit of a squeal/whine at times.

If you watch the tire spinning video, a split-second before the wheels start to spin, you can hear it.

Did you notice that at all when you were testing it? Is it part of the PI looping thing? It seems to happen when accelerating.

This video is also one of the few times I have HEARD the Metro in action. Inside the car, it's kind of loud, because most of the interior is removed. On the outside, all you hear is traffic, the wind, and flying gravel!

[Blue Bomber Man]

I might be interested in doing some work in Solidworks for this project, but it would only be to the extent that the Drawings would be a good visual aid for how parts are put together, and would be useful for moving things around.

I don't think I would be taking the time to make every detail visible. For example I wouldn't bother putting screws and what not, but it would have a post that represents where the screw would be.

To do this would need accurate measurements of components, positioning etc.

I then could have solidworks convert the 3d entity to some drawing files that I believe would be viewable with free software. It might be able to allow you to look at the 3d image as well and pan it, etc, but not edit it. Of course anyone with Solidworks or other compatible software could open up the files for their own use.

[MPaulHolmes]

Originally Posted by bennelson

Hey Paul,

I believe the controller is making a bit of a squeal/whine at times.

If you watch the tire spinning video, a split-second before the wheels start to spin, you can hear it.

Did you notice that at all when you were testing it? Is it part of the PI looping thing? It seems to happen when accelerating.

This video is also one of the few times I have HEARD the Metro in action. Inside the car, it's kind of loud, because most of the interior is removed. On the outside, all you hear is traffic, the wind, and flying gravel!

It is the hardware over-current shutdown coming on, and going off again super fast, oscillating around 480 amps(???) or so. I have some ideas about how to fix that. When I had a long delay after each over-current shutdown, it would make a lower frequency buzz. Now that I got rid of the delay, it's turning off for a shorter period of time, and then turns the mosfets back on.

One thing that should help is using the 300 amp current sensor, which still has a range of 900 amps. It will give me almost double the resolution of the 500 amp current sensor. Instead of 0 - 500 amps corresponding to 0v to 0.6v current sensor output, it will be 0-500 amps <--> 0v to 1v. Not great, but better. I'm also going to try some things that will reduce the noise, like sampling at the same point on the PWM wave each cycle.

MODELING: I have never done any of that! That sounds like a great idea for really making clear directions. The problem is, I need a fixed predictable supply of power section PCB (4 or 5 ounce copper would be really nice!). Right now, the directions would be bent toward using the supplies and dimensions of PCB that I have available, rather than toward optimal functional design. I have enough 3 ounce 2 sided PCB for maybe 40 or 45 controllers. It's not perfect, but the price was right ($1 each!).

By the next version, I'll try to be really careful about the dimensions. I was sort of just winging it on this one, since I have to finish it before May 2nd, so I can go to the Lacey Alternative Energy Fair. I'm almost done, though! I've been using ExpressSCH, which is a circuit modeling software. I could convert that to a .jpeg which could then be turned into something nicer with professional modeling software.

It's getting much much easier to make one from start to finish. After a bit more practice, I bet I could do one in like 1 or 2 days!

[Wherewolf]

This forum is truly amazing. I’ve been following it for some time (lurking!) and have been incredulous that so much has transpired so quickly. I decided I had better contribute to the cause to help pay for Version 2…funds transferred….
I do have some manufacturing and mechanical background - I'll help if I can. I also have some experience setting up non-profit educational foundations, if the members decide to truly make it an open-source educational foundation. There are some paperwork costs, but my labor would be donated. Just something to consider to protect members from any liability...

Kudos to all! Keep up the good work – I can’t wait to get started on building one…..

Wherewolf

[Tango Charlie]

Originally Posted by bennelson

I am going to make it into a sleeper and race for pinks.

I can see the TV show now...
"Ben and his ElectroMetro, ridding the streets of one polluting, gas-guzzling hot rod at a time..."

[ev59rag]

Or you can use Sketch-up too for the modelling... Its so easy my 10 year old daughter loves it. And its free.