What does "direct drive" mean?
1964 Corvair EV conversion (EM-EV)
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hey @mitchhodge Thanks! It continues to be a great experience for me. I am glad to hear you are on your journey! I am also happy to share more info on my shifter process. As for the gas gauge, I can share the code and the CAD file with you for the servo motor mount. Send me a DM and we can exchange contact info?
My "direct drive" solution, using a 3spd in 2nd is working out fine. I did end up swapping in a 4.11:1 gear set from Clarks in my differential for better acceleration, at the expense of top speed. If you do lots of prolonged highway speed driving, you might need to actively cool the motor. Running continuously at those high RPM can warm it up a lot. I added some vents to get more passive cooling for my motor and it seems to work, but i live in a very mild climate.
For the shifter, this is what i did. I ordered three of these hall effect sensors: 55100-3H-02-D - Littelfuse - Hall Effect Proximity Sensor, Flange Mount, 55100 Series (newark.com) I chose these cuz they are a great size for this application, seems rugged and have the right operating voltage. I wanted something in a larger package so i could mount them with doubled sided molding tape.
These are the three wire proximity sensors. They take 12V in, and ground on the red and black. The blue is the signal... either on when a magnet is present, or off by default. I would suggest you get a small breadboard setup like the pic above and test it all with LEDs. It might need some tuning. They connect the negative leg of the LED to ground when the "on". The pic above is high res enough to see how i wired up the LEDs.
Magnets: i drilled small holes in the white slider part inside the shifter mechanism. I placed 3 magnets that were about 1/8in diameter and 1/8in long. I get my magnets from here (along with everyone else, i reckon): K&J Magnetics: D22-N52 (kjmagnetics.com) You may want to get a small selection of magnets around that size, just in case you need to swap in something stronger or weaker. Its important you get the axial magnetization.
The plan: I figured out three spots on the white plastic slider that will accommodate magnets, then i noodled on where to place the hall effect sensors on the black cover. This is the theory of what i did:
Here is the setup: Those are the approx locations of the magnets and sensors for my setup. This explains my theory.
Neutral, none of the sensors are "on":
Reverse, the right sensor is "on":
Forward, bottom sensor on, right sensor off and top sensor off: This is D for my car.
Forward with regen on neutral, top AND bottom sensor is on, right sensor is off: this is L on my car.
So, as you can see, this whole thing will need some tuning. Like i mentioned above, the reason i like these sensors is that they are in a nice package. One of the ways i planned to tune it was to add space between the sensor and the black housing with extra layers of double sided tape. The sensors can be moved left and right and up and down, so that breadboard is really important to tune the system. You will also want to spend time jiggling the handle, trying to get the sensors to trigger with vibration or super slow/fast shifter motions. This is required to make sure your setup is robust to variation. I dont remember the sensors have tons of hysterisis, but that is something to keep in mind.
Like this:
I was able to tune my setup with just moving the sensors left and right, without the need of extra layers of tape to increase the distance from the magnet. After I got all the positions all right, i cleaned up the surfaces, and use some strong 3M molding tape to hold them in place. Then i put a zip tie around them all to secure them during installation and wiring.
It takes some work for sure! but the stock look is worth it to me. Good luck and let me know how it goes! I hope this helps.
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