Electric Ninja

The team I've been working with for the last few months won the grand prize at the Environmental Innovation Challenge on Thursday. The car we submitted was a working prototype with three seperate controllers interfaced together to create an electronic differential. The entire systems is very modular and was bolted into the original motor mounting locations. 

Seattle Times Article:

http://seattletimes.nwsource.com/html/businesstechnology/2014653636_cleantech01.html

Voltaic Drive Systems Team:

Quick post for today so I can get back to studying for final exams.

Since nothing on the stock wiring harness worked when the donor bike was purchased, I assumed getting the headlight, brake lights and blinkers functioning properly would be more than a weekend long process. However, after spending several hours diagnosing problems, varying from poor switch connections and splice jobs to corroded copper wire, every single light on the bike ended up working flawlessly.

I had to rewire the headlight 10 amp through the unused 10 amp ignition fuse because some of the old relays in the fuse box weren't useable after removing the starter switches.

Lights!:

Because I wanted to lower the center of mass on the bike and remake the busbars on the batteries with thicker copper sheets, I am now using fewer batteries and a 28 series 4 parallel battery orientation. At first I wasn't sure what to do with the newly opened space on the top battery pack. It just so happens that for the past few weeks I had been considering purchasing a Manzanita Micro PFC-20 9000 Watt charger to communicate with the Manzanita Micro battery management boards. The charger can turn down the output battery side power when the boards start to shunt. Even better, the charger would allow for more than half the charge time from my old charger, and it fits perfectly in the newly opened battery area. I am graduating next week and it sounded like the perfect graduation present to me. Weird huh? You thought your 1000 watt PC power supply was powerful? Try over 9000 Watts.

Manzanita Micro PFC-20:

As of last weekend, the bike is running.

After countless trips to Lowes and Napa, I picked up all the stainless steel bolting hardware and fine grit sandpaper needed for a solid connection between the high voltage hardware. I also made a new ground on the bike and installed a temporary switch to turn on and off the controller without activating the 96 volt battery pack. The ignition key is then used to power up the main contactor after the controller is running.

There are some really intuitive custom gauges on the Synkromotive controller user interface which I set to monitor motor and battery current for the moment. The computer with the user interface installed can even store data logging from the controller. Overall I'm very happy with the controller and more than satisfied there are no issues with external contactor precharge circuitry.

The laptop communicates with the controller through a LAN to USB adapter:

My handmade busbar connecting the main contactor and positive battery controller terminal:

There is still a bit of tweaking expected and low voltage lighting wiring needed for a rideable status. 

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: