17 January 2014

EtekChopper: Further System Integration and Testing!


Last we left off, the batteries and controller were ziptied to the frame for temporary testing, and the motor was mounted with a waterjet aluminum sprocket at only two points. The point of this is to get the bike to the point where I can ride it around and prove that everything will work. Then, I will take everything apart and put it back together in a clean, final, ziptie-less fashion. 

The electronics and wiring were certainly a mess, but they will do for now. At least I have some idea for how many wires I'll have running around. 

Next I decided to mount the new 56-tooth rear sprocket. I have drilled the proper mounting holes, but the main hole where the axle passes through is too small. 

Using the indexing head on the mill, i was able to mill out the proper sized hole to mount the rear sprocket. 

And on she goes! With all the torque my friend Adam and I can muster. That's 100ft-lbs, right? 

I mounted the motor sprocket (I flipped it over from the way it is shown here). I cut a piece of keystock I found lying around MITERS to the proper length, and cranked down the beefy setscrews to the shaft of the Etek. 

Next came installing the new chain. I moved the rear wheel as far forward as I could in the chain tensioning slots (to ensure a loose chain) and wrapped the chain around the entire front and rear sprocket. I placed the master link on one end, and pulled the other end on top and marked where I was going to cut it to size with a black sharpie. 

The chain cut easily enough with an angle grinder, and the pin (shown intact above) fell out when I cut down on one en long enough. 

Now all I had to do is place the master link through the chain...

Et voila! The chain is attached and I can move the rear wheel, and the motor turns!

The chain looked straight enough, but I am still worried about it not actually being straight, or it contacting the rear swingarm while running. I may want to make the front motor mount adjustable to ensure minimal misalignment and stress on the chain. 

For now, this standoff on top and spacer on the bottom should suffice. The issue with this is when there's tension on the upper part of the chain, the whole mount will deflect and possibly oscillate. That's why there's a third (not visible in this picture) hole at the bottom left of the motor mount for putting a third brace of some kind. I will weld a tab onto the frame and drill a hole in that tab for the third standoff. 

I installed the Cycle Analyst's shunt resistor on the negative terminal to the controller. I love working with large power bars, because that means my terminals and rails can be minimally structural! Look at those aluminum/copper bus bars! :D

The speedometer of the Cycle Analyst works with a hall sensor and a magnet. The sensor is attached to the front fork with zipties, and the magnet is epoxied to an unimportant part of the front brake disk.

After tying the Cycle Analysts's B- shunt probes and B+ probe to the appropriate wires, I turned the motorcycle on to find this! Way cool! I ran the initial setup routine, which included inputting the front wheel circumference and other options. 

To test the speedometer, I lifted the front wheel up and employed the help of fellow MITERS-folk Charles Franklin who is making a really nice scooter of his own! His scooter theoretically goes about 20-25 mph, so if we push his drive wheel into mine and run it, my speedo should read about the same. 

And so it does! (It reads negative Ah used  because I had the shunt terminals backwards...) With everything in place, it's time for a quick test of my system in the parking lot outside MITERS!

Hand-me-down helmet, no jacket, no boots, no lights, no front brake (The rear drum brake works fine though!). Safety third! (Please don't do stupid things like I do, or you may end up like this poor bastard). 

Well, here goes nothing! 

It all works alright, but there seems to be some shaking/vibration when there it too much torque being applied by the motor. I'd attribute it to loose electrical connections, or the motor mount needing further constraint. Either way, I'll tackle the issue later. For now, the entire system works well enough for me! 

The chain sound is normal, though it sounds pretty nasty. Turns out the original internal combustion engine was enough to drown out the sound of chain. Other electric motorcycles sound the same, so I'm not too worried about it. That may be why Zero Motorcycles use belt drive for their ECycles. When I kick it up and rev it though, it sounds soooooo cool! :D I can't wait to get on this thing and really feel the amps working underneath me. 

I purchased an inexpensive cover for it before the fall 2013 semester got tough, and here it remained until January 2014. Next up is tearing it apart and cleaning/welding mounting tabs/repainting everything!

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