Wiring to eliminate reverse

[MPS1982]

Here's what I've come up with to run a shaft out of the open end of the motor. Currently this is a plastic 3d printed part but I have plans to make a mold of it and cast it in aluminum.

[JohnnieB]

Originally Posted by MPS1982

Target speed is 25mph. I am using sprockets and chain to drive a jack shaft which will have a 2in friction drive roller contacting the tire. I had considered pulleys and belt driving the rear wheel, but the ratio was too difficult to achieve. For reference, my rear wheel is 24in dia.

Is it 24" rim diameter or 24" tire height?
If it is a 24" tire height being driven by a 2" diameter friction roller, you have a 12:1 gear ratio if the tooth count on the sprockets are the same.

That should give you 25 MPH when the motor is spinning at a whisper over 4200 RPM and standard speed series motors used in golf carts typically max out at about 3200 RPM with a 36V battery pack, so it might be a good idea to look for a high speed series motor if you are going to run at 36V, which is the max voltage for the 1204-009 controller.

Originally Posted by MPS1982

Here's what I've come up with to run a shaft out of the open end of the motor. Currently this is a plastic 3d printed part but I have plans to make a mold of it and cast it in aluminum.

Might want to look for a hybrid front bearing (Ceramic balls) since it will be within the magnetic fields produced by motor. (It will work fine with steel balls, just won't last as long due to eddy current erosion.)

Elegant solution for the blue thingy.

[MPS1982]

Originally Posted by JohnnieB

Is it 24" rim diameter or 24" tire height?
If it is a 24" tire height being driven by a 2" diameter friction roller, you have a 12:1 gear ratio if the tooth count on the sprockets are the same.

That should give you 25 MPH when the motor is spinning at a whisper over 4200 RPM and standard speed series motors used in golf carts typically max out at about 3200 RPM with a 36V battery pack, so it might be a good idea to look for a high speed series motor if you are going to run at 36V, which is the max voltage for the 1204-009 controller.



Might want to look for a hybrid front bearing (Ceramic balls) since it will be within the magnetic fields produced by motor. (It will work fine with steel balls, just won't last as long due to eddy current erosion.)

Elegant solution for the blue thingy.

I must say, you are doing a fine job following along here! I failed to mention my motor side sprocket is 20t and friction drive sprocket is 16t. I designed around the assumption that I'd be able to get the motor up to 3K rpm. I should be right about 25MPH if I hit 3200.

Any tips on where to find a used series motor for cheap? I have a tight budget for this build and a new motor pretty much folds this one up.

Oh and by the way, the size of the rear wheel is irrelevant in this drive set up. The friction driver surface speed will match ground speed regardless of wheel size. I could have a 3" wheel and I'd have the same speed and acceleration characteristics. But I want the huge wheels so it's a smooth ride (saves me the trouble of coming up with a suspension). Plus, it looks more ludicrous. Wheels are from a Suzuki gsxr

[Helirich]

Originally Posted by MPS1982

Here's what I've come up with to run a shaft out of the open end of the motor. Currently this is a plastic 3d printed part but I have plans to make a mold of it and cast it in aluminum.

That's pretty cool. Is it reasonable to get it cast? I don't think it would be hard to machine the end out of a piece of aluminum. Your going to have to machine it anyways. What's the plan for batteries?

[Clemsoncartguy]

I was wondering about batteries. Even 3 12v is gonna be heavy and trouble stowing them I would think?

[MPS1982]

Originally Posted by Helirich

That's pretty cool. Is it reasonable to get it cast? I don't think it would be hard to machine the end out of a piece of aluminum. Your going to have to machine it anyways. What's the plan for batteries?

I'm am hoping to cast it myself. Ive built a little foundry and have been trying to learn mold making and casting in my spare spare time. I've successfully melted down a few lbs of aluminum but my castings still have a lot of room for improvement. But the all important cost will be ~$0 if successful.

From what I have seen, with a small enough particle size in the mold sand, the cast part won't necessarily need machined. I've seen people cast parts that have come out shiny. Traditionally, post casting machining would have been done to guarantee concentricity or other dimensions that couldn't be held by hand made patterns, but my 3d printer's resolution is 0.25mm so should dimension ally, should be good to go if the casting goes as well as I'm hoping.

Originally Posted by Clemsoncartguy

I was wondering about batteries. Even 3 12v is gonna be heavy and trouble stowing them I would think?

my thoughts exactly

[MPS1982]

Here's one of my 3 batteries and a picture of my aluminum foundry.

Batteries are small, certainly not enough to run all day. I'd be thrilled if it could cruise at speed for an hour. This is very much a novelty. I imagine using it to run to the grocery store or around town. I'm not commuting on it.

15 AH... that's really low

[MPS1982]

Originally Posted by Clemsoncartguy

I was wondering about batteries. Even 3 12v is gonna be heavy and trouble stowing them I would think?

The batteries will be contained inside a tunnel that runs between the riders feet. The size of the pack all together is 12"X6"X4"high.

If in the future, I'm happy enough with all other aspects I can always upgrade the batteries.