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Thread: Southern Polytechnic State University

              
   
   
  1. #11
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    how's it looking for 2014?

  2. #12
    Senior Member EVGator's Avatar
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    For 2014, we plan to compete in 2 or 3 of the eMoto-Racing events. The first race is at Roebling Road near Savannah, GA and isn't too far from us at all. The series is inexpensive and allows us to use more of our budget on the bike itself. We are currently:

    -Rebuilding the battery pack with most of the design work complete.
    -Awaiting the arrival of more LiPo cells to replace damaged cells from the crash.
    -Talking with Linear Technology about using 3 of the LTC-6803 Demo Boards for our BMS.
    -Researching the feasibility, in terms of space and cost, of implementing an "Active" balancing system for the BMS to "shuffle charge" around the pack during charge and discharge. Using capacitors to do so is cheaper than using flyback transformers, it just takes longer. This would allows us to get the most out of our battery pack despite small differences in capacity, and extend our range.
    -Shedding weight everywhere that we possibly can.
    -Using the same motor and controller combo unless sponsorship deems otherwise.
    -Looking into a wireless data acquisition system for monitoring the bike during the race. If not wireless, we will at least log data to an SD card.

    Doing some calculations and running a simulation with a C++ program, we will use around 4.5 kWh doing 8 laps at Roebling road. We shouldn't have any problems at this track with our 7.5 kWh battery pack, and plan to hopefully adhere to the 80% DOD rule for the season. We'll see.


    And of course, if sponsorship permits, we will do as many races as possible. I'll keep you posted and hopefully have some photos this week.

    -Tyler Rowan

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  4. #13
    Senior Member EVGator's Avatar
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    We stripped the bike down to prepare for 2014 a few months ago. We also have the controller mounted in the tail section of the bike to allow for more battery space, and to avoid ground clearance issues.

    CAM00764.jpg
    CAM00842.jpg
    CAM00843.jpg
    Last edited by EVGator; 19 January 2014 at 1907.

  5. #14
    Senior Member EVGator's Avatar
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    CAM00993.jpg The battery discharging station prototype is working. We are able to move the lead across the Nichrome wire to "variably" adjust the discharge rate. Data is pulled in through the Arduino and logged. The goals are going to be to add more thermistors (only one located inside wood block), make a more permanent station, and test an entire module (1s12p) with discharge rates that will be seen on the bike itself. Then we will take this data and make graphs for each module and compare them.

    A fellow team member is developing for Google Glass as you can see them on his face in the picture. Hmm...I wonder if our rider would be opposed to a HUD on his face!

    CAM00999.jpg



    *I'm waiting for someone to make the comment about wearing rings while working on electrical and electronic systems. Luckily this student didn't arc weld his ring to his finger.
    Last edited by EVGator; 05 February 2014 at 0029.

  6. #15
    Senior Member EVGator's Avatar
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    Thanks to our sponsor Linear Technology, we've got some LTC-6804-1 bms demo boards to use with our battery pack, a USB controller for the software monitoring, and a Linduino one board. Each 6804 board can read up to 12 cells in series, and we are using 3 boards for 30 cell modules in series. The 6804 is supposed to work better in the presence of EMI interference than the previous 6803 chip series. The software allows us to watch the entire pack during charging and interrupt the charger to balance the modules accordingly, at <200mA. We've also got a 1A LiPo balancer that we can use for individual modules. Next, a program will be written for the Linduino to grab the serial data from the 6804 boards, in order to gather pack temperature data and cell level info. This info will be sent to a display (likely with idiots lights) during bike operation, so that our rider will know if there is an issue with the battery pack. It seems simple enough for now to get us going, but we expect to add data logging, gps, and or live data streaming. Who wouldn't want to watch an entire battery pack perform live as it's discharged around a race track?
    bms.jpg

  7. #16
    Senior Member yankee1919's Avatar
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    Awesome,

    Really enjoyed your build, keep us up to date.

    Tony
    Los Angeles

  8. #17
    Senior Member EVGator's Avatar
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    Hello elMoto, I hope that everyone is doing well and perhaps getting some electric miles logged as the weather warms up. Here is some news from the lab.

    Our Electric Vehicle Team has worked through a number of problems and challenges this semester, and continues to do so. One of the most notable problems includes:
    -Our Curtis controller for the race bike was damaged after a student who shall remain nameless incorrectly used a cable that we built to program our Curtis 1238-7601 from a laptop. The cable originally worked great, but was used in an incorrect manner while still in the prototyping stages. This resulted in some sort of ground fault between the controller and the desktop computer that the student was using, frying a component on the controller logic board that allows for communication. After freaking out and questioning whether this would potentially ruin our racing season, I am proud to say that we truly came together as a team and took shifts troubleshooting the logic board for the controller. After finding a damaged zener diode and taking appropriate measures to fix the board, the controller is now functional, and we have a working racebike. None of us ever claimed to be professionals, but the season is saved, and we still love "said student". This was a great educational experience, and allowed us to learn the inner-workings of the Curtis 1238-7601 controller; something we otherwise would not have attempted. I recommend that you DON'T try to build your own cable without proper isolation, as we are not the first to have this happen to the controller. It took a lot of time and troubleshooting to fix, and we are lucky that our season isn't ruined. So enjoy these pics of the insides below, as you likely won't see them anywhere else.

    The infamous Logic Board:
    CAM01046.jpg
    The Driver circuit:
    CAM00785.jpg
    Lots O' FETS:
    CAM00786.jpg

  9. #18
    Senior Member EVGator's Avatar
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    As for other news,

    -Our new battery boxes are out of the design phase and currently in the build phase. The picture below shows the box at its most basic form, but it is rugged, insulated, and will transfer heat to the outside of the box much more than a solid plastic pack. The black plastic used for dividing cell modules is Marine grade HDPE, which was chosen over ABS because of cost, weight, and thermal conductivity. More photos will be posted when the boxes are finished.
    -1110051895.jpg

    -As a team, we have discussed several different methods of connection for our cells. Our modules consist of 12 5AH LiPo cells in parallel, and must then be put into series with other modules. We wanted the removal and installation of modules and even individual cells to be easy, but this method can only be done using compressive force, and bussing. The other option is to solder (as spot welding tiny 5AH cell tabs isn't ideal) or use spacers between each tab and run a buss/rail through all 12 tabs. While we still debate this issue, we are keeping safety and the ability to transform the cells into a higher voltage pack for the future, in mind. Does anyone else have any input on this?

    We are still planning to race the Barber Motorsports Park round in eMoto-Racing, and will definitely have a track day during summer. Our University is planning to consolidate with another one nearby, and I will list that info below. We may have to change our name and branding after the consolidation, but are excited about the research and financial opportunities that the consolidation will allow.

    Release:

    The Past:
    The Southern Polytechnic State University Electric Vehicle Team. We are a group of passionate engineering students that attend SPSU, the small engineering school you've never heard of. To give a bit of history on the school, Southern Tech was founded in 1948 as a branch of Georgia Tech for WWII vets who needed practical engineering technology education for the industry. The Southern Technical Institute went on to make a name for itself as it later separated from Georgia Tech. The school went through a few different names throughout the years until arriving at SPSU. The primary focus of the campus has been "applied engineering", and the school developed a great relationship with companies in Industry (like nearby Lockheed-Martin and KIA) as students graduate with a great balance of practical and theoretical knowledge. The school of engineering and the school of engineering technology achieved a perfect score during the ABET accreditation process last year, being the first school to do so as claimed by the ABET representatives.

    The Future: SPSU is set to merge with nearby Kennesaw State University to become a powerhouse, research fueled, Division I University. The Southern Polytechnic College of Engineering and Engineering Technology will become an integral part of the new University and new opportunities for research are being explored. This is exciting for us, as we will likely have a larger level of financial support to dabble around the world of electric vehicle technology and application.

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