Paul & Sabrina's Cheap EV Conversion

[Intrigued]

Originally Posted by MPaulHolmes

How much torque do you do on the bolt that has the cotter pin through it?? I didn't know when to stop. boo hoo. The wheel still turns nicely, though.

Something on the order of 20 foot-pounds. (your feet, not Oprah's...) Find a spot that has a good stout pull to it, that still allows the slots in the nut to align with the hole, so you can use the cotter pin.

As for what to call the other parts, you've got me so confused I'll let Christ handle that one...

[MPaulHolmes]

ONce I post the video, the wiggly things will all become clear. oh ya!

I tested the car, and there is NO SHIMMY ANY LONGER!!!! OH RAPTURE! I took that bad boy all the way up to 38 mph, then I had to stop at a light. I also drove in 3rd gear for the first time ever. It felt all tingly all over! It was fun! Very solid feeling now, not sloshy and banging!

[Christ]

Sears, $60 for a lifetime alignment (used to be, might not be anymore, since K-Mart took over.)

The second "wiggly" part is an inner tie-rod end.

[Intrigued]

Originally Posted by MPaulHolmes

I tested the car, and there is NO SHIMMY ANY LONGER!!!! OH RAPTURE!

HOORAY!!!

Take the thing to a front end guy somewhere and let them tell you if any of those other bits should be replaced! No use doing what you don't have to - or can't afford...

[metromizer]

Sorry I haven't been keeping up with this thread...

Paul, you want to remember this, it matters when dealing with VW only parts houses with respect to your front end parts. You have what is commonly called a "flat windsheild super beetle" How do I know? I can see it has Mac Struts from the pictures you provided. The infamous "Super Beetle Shimmy" is usually traced back to the pivots at the very top of the strut assembly <seen from the trunk area>. I incourage, <or some stronger word without sounding like I'm telling youo what to do> you to reaaly give those pivots a close look and consider they may very well be the culprit. My buddy with the VW shop just passed this summer, or I'd ask him how to test them.

Way back in an earlier page, I am pretty sure I described how I go about checking for worn front end parts on an air-cooled VW. You should do that, but I can't tell you how to test for bad pivots.

I can't tell if you found worn out tie rod ends (the things your diagram says are wiggly) or not. I'm not going to describe this very well in words, they come moveable from the factory, but shouldn't clunk when the steering wheel is moved back and forth... not sure if that makes any sense.

SB's also have two universal joints in the steering shaft, between the steering wheel and the steering box, that occasionally go bad. Also, the connections sometimes loosen, the steering box's pitman arm pitch bolt sometimes looses up. Sometimes it's just a matter of bending back the locking tabs, tightening a bolt, and re-bending the lock tab in a slightly new location.

If you were in NorCal I'd offer to just come over and diagnose it for you, it would take less time than writting this out.. LOL!

[Christ]

Check for the pillow mounts for McP strut systems: remove the lower attachment point on the strut, leaving it attached to the body/chassis of the car.

begin wiggling. immediately, the side to side movement should feel arrested, any loose feeling to the motion is cause to replace the bushing/mount.

Recommended replacement interval is something like 60k for newer ones. You can get away without replacing them in most cases, but a visual inspection is necessary. My wife's GP has a nice plate on the top of the strut mount that actually stops the strut from contacting the hood. It also prevents the strut from pushing through the hood in the event that the rubber bushing fails.

A pretty standard upgrade that will also help to stiffen your ride a little bit (attenuation of lateral movement) is to use ball mounts instead of pillow mounts. These are essentially solid, but employ a heim joint's "eye" as the location where the strut's piston actually is mounted.

[MPaulHolmes]

I attached the logic for my home-made controller. If you have any C/C++ experience, Atmel has an awesome free development environment that is really easy to learn how to use. Anyone can use my code however they want. It still could use some extra features like current limiting and stuff like that. It's heavily commented.

I think my first attempt is going to be an upgrade to my electric bike. Right now I'm using a 20amp 48v controller. I'll use maybe 100v mosfets so I can jack up my max speed a bit.

[MPaulHolmes]

I got an oscilloscope today. It was $126. Almost new! Regular price was like $710. 50 mHz 2 channels. I also ordered an STK500 atmel microcontroller programmer and 2 ATMega8 chips. So the code on the computer can finally be sent to that little $1.50 ATMega8 chip that will be responsible for putting out the pulse width modulation from the throttle, monitoring battery level, monitoring temperatures of whatever I want, etc.

My first draft will be an upgraded controller for my bike. Then I'll be looking at maybe 300 or 400amp 144v controller for the car. I found a cheaper source for some big IXFX 120N20 mosfets. They will only be $13.15 each. I'll need like 6 or 10 of them for the car controller. The whole cost will be maybe $300 or so, but first will be the bike controller. I know this sounds sort of ambitious, but I know I can do it. A brushed DC motor controller is actually very simple. The devil is in the details, though. If I have the money, I might be able to finish it by the end of the summer? Well, things are always much harder than you think they will be. I'll be sure to show updates about the progress.

[bennelson]

End of the summer? So you are thinking by Oct 2009?

As to building your own controller, go for it.

I am constantly amazed at what I have done in the last while simply by not letting my ignorance stop me from doing something!!!

[MPaulHolmes]

Originally Posted by bennelson

End of the summer? So you are thinking by Oct 2009?

very funny, you whippersnapper!

I agree about just trying stuff and not quitting gets you amazing places! I'm starting to believe that almost nothing is impossible, except for eating the whole world in 1 second. (must resist... must resist...)

I have had many times where I couldn't figure my way around a problem, and just kept beating my head until it was solved.

Oh ya, I bought a heater for the car! A whopping 150 watts! Wow! Only $11. 12v. It has a fan too, so the "slightly warm air" gently blows on me as I drive.