Electric Ninja

I'm going to write a quick post how to use my electric vehicle performance calculator accessible in the downloads section (64 bit windows only at the moment). After a year or so of putting off getting this program completed, one of my parent's friends was kind enough to let me use his own personal Matlab compiler to turn it into an executable.  

1) To start a simulation, press run. This interface will be used every time a simulation finishes to start a new one. However, the previous values for both the torque curve and vehicle parameters will be set as defaults.

2) Enter vehicle parameters. The first gear ratio is the drive ratio between the motor and wheels.

3) Select whether or not you have a second gear shift.

4) Select shifting parameters. Your first gear will not effect top speed calculations if you select this option.

5) Select the data source for the torque (ft-lbs) vs RPM plot. Either enter a new one or load a premade plot.

6) If you choose to enter a new plot, you can only left click to enter new points at the moment and not right click to delte them like the tip says. This is definitely not intended and will be remedied in the 32 bit version. What the program does here is it creates a polynomial with an order one less than the number of points entered. Place points at the edge of the plot and place points close together at any sharp angles for the best fit.

7) If you choose to use a premade plot, you can browse your computer for a txt file with the torque vs RPM data. The next time the program is run there will be an option use the previously used data. If edit or add points is selected, you can now right click to delete unwanted points and left click to create new ones.

8 ) Press enter to see the results!

Top speed:

0 to ? mph:

Quarter mile times:

My goal is to have the bike running by March 16th. Of course there will still be many months spent afterwards tweaking the user interface and refining the bike. This goal means setting aside a few design issues, like rebuilding the battery packs with thicker copper bus bars and finding a way to slightly reduce the size of the lower battery pack to fit inside stock fairings.

Other more pressing issues come to mind like bolting the motors into the frame without creating any large stress concentrations. Welding the aluminum created slight warping in the mount so I'm considering using a rubber damping material to distribute the load more effectively. I also would like to have better access to the motor terminals since there is little clearance in the mounting frame. This should be easily solved by trimming back the large aluminum mounting plates slightly. Luckily, doing so will have no effect on structural integrity, it will only take more time.

Honestly, until last summer the blog has been somewhat of a joke, and more of a log for myself than anything else. I realize I've done a terrible job both maintaining and updating it, so I'm going to make it a point to post quality updates regularly from now on. In light of this, here are some pictures taken back in August and Spring of 2010 of the motors in the bike frame.

Downtube attachments:

Side view of the bike taken at Manzanita Micro in Kingston (Notice the freshly painted rims and new tires!):

Quite a few parts for the bike are scheduled to arrive this weekend including some double walled color coded glue infused heat shrink, 700 amp fuses, and heavy duty tinned copper lugs. I also ordered a smaller bore sprocket to fit on the single motor shaft so I can get the bike running with one motor just for now.

The Agenda for this quarter:

-Bolt in motors and set chain to the proper length

-Lay out components where they will be bolted into place

-Cut cable to length

-Crimp lugs making sure to bend the cable as they will be installed

-Heatshrink lugs

-Bolt on finished cable

-Complete low voltage wiring

-Start the bike!

 After a series of setbacks, the production Synkromotive controller arrived at my house from Portland Oregon. There are now high hopes ZXE will be operational by the end of this quarter *exasperatedsighofrelief*. The wiring diagram has been finished for a few weeks now, so from here on out it's time to cut, crimp, solder and heat shrink!

Here's a screenshot of my wiring diagram, put together with Microsoft Visio:

The 156 Volt, 700 amp controller is being run at 96 Volts for the pack I have at the moment. The Synkromotive is a beautifully designed controller. Weighing in at about 6 lbs, air cooled and USB programmable it has quite a few advantages over other controllers on the market right now. I know that the next production run of the controller has the potential to do 1000 peak amps which means it is a competitor with the Cafe Electric Zilla 1k. There are noteable advantages though over the ~30 lb water cooled Zilla that make it ideal for my project.

Negative lower terminal and upper positive battery terminal sticking out to the left:

The nicely labeled wiring harness is much appreciated:

There have been some pretty significant changes on ZX-E as of late. I'm going with dual k91-4003 6.7 inch series wound DC motors now. These are smaller than the 8 inch diameter motor I was originally going with. I completely redesigned the motor mount and managed to incorporate the battery mount into it, which at the moment seems like an advantage as far as simplicity and space management goes.

SolidWorks model of the bike frame and powertrain Alex and me drew up:

The finished mockup of the motor mount, the stacked battery mockup, and the controller all in the bike allow us to see how exactly everything will fit together and make sure the gas tank will properly fit on the bike. Mockups are definitely key before the mount is fabricated, because any slight miscalculation in how the design fits inside the frame could call for more than one visit to the water jet. Of course this would call for additional manufacturing and material costs.

Pre-production version of the Synkromotive controller sitting on the battery and motor mount mockup:

The project is really shaping up and we've finally settled on a design that is simple and effective.