I always liked mini bikes and go karts. I got my first Briggs and Stratton 3hp minibike when I was 6. by the time I was 8 i had shaved the head to make more power. I decided to make an electric powered one. That way there is less noise and more fun. I thought maybe the lack of engine noise would detract from it but it made it better. I was able to sneak up on my wife one night as she came home from work. She never heard it coming....
Step 1: Picking a Motor
I thought about using a number of different motors but I had this GE 36V motor that had a base mount very similar to the mounting pattern of the gas engine so it made life easy.
Step 2: Picking Batteries
I really the baby Hawkers or the Cyclon for their low internal resistance but I ended up going with large gel cells for range. turns out they are pretty good on power too. plus with only 3 batteries in a nice rectangle configuration I was able to make a frame from old bed frame angle iron and used a single ratcheting strap to secure them
Step 3: Picking a Controller
I wanted good control so I used a Curtis controller from a forklift. I mounted it to an old car amplifier shell as a heat sink.
Step 4: How to Back Up
At some point you will need to back up. I pulled the reversing contactors out of another golf cart and used some copper battery straps and copper tubing to mate them together in a nice neat small package. too bad the wires are so big...
Step 5: Wires and Connections
Luckily I had plenty of scrap #2 wire from an old UPS. I use the hammer style crimper tools to attach the lugs. I like to wrap the finished crimp with tape. It doesn't matter what color tape since I then cover that with heat shrink tubing. It makes the ends look really neat. Even better than the "Professionally" made battery cables I looked at. I used good quality battery disconnects to minimize losses in the high current wires.
Step 6: The Frame
I had a collection of frames and old tractor parts. There was one nice go cart with a full cage. It had solid suspension so I cut the front end off a cheap Chinese made ATV I got on Craigslist for $25 and welded it to the front. I used a tiller steering arm made from old 1" square steel tubing I got from a commercial clothes rack I found in a dumpster. For the rear I used a Collection of parts from all the go cart scraps around the yard.
Step 7: Gears
I had some Motorcycle chain laying around. I think it was from a Suzuki 750. I couldn't find a decent drive gear to match the big motorcycle driven gears then I went to Tractor Supply and found these make your own gear parts. You buy the correct size hub to match your motor and then buy the correct tooth and pitch gear and just weld them together....
Step 8: Running Gear
I ended up using some pillow blocks and kept the rear solidly mounted. I had a lot of different wheel hubs from 3 to 5 bolt models. I turned down a wheel hub on the lathe to fit a disk brake rotor. At some point its good to have brakes. I had to reverse the rear disk brake to get it to clear the ATV tires.
Step 9: Last But Not Least
A big red handle to help pull the battery cable in an emergency. Luckily I never needed it.
it even has a dashboard that was recycled from a Caterpillar diesel generator. check the movie to see its final test.
the most important feature of the dash is the big red button that drops all the contactors and shorts the motor too.
Step 10: Addendum
After a while that solid rear suspension started to hurt in the end, literally....
I cut the rear frame and welded the Dana rear end from a EZGO in place complete with nice soft leaf springs....
This also made it faster and prone to hairy wheel stands even with a 300 lb driver....
Next step is front ballast weights or maybe a plow. that way i get the weight balance and another useful tool for the winter....