Vacuum forming terminal covers

So, when you order from China, sometimes you do not get what you need.  When we originally ordered our Thundersky cells from the distributor, we did not get studs, washers or terminal covers.  After several failed attempts to contact the distributor, we finally decided to take matters in our own hands and make our own covers.
  This year, the EV Challenge officials have required that each cell in a battery pack must be covered.  A single cover over all batteries/cells will not suffice any longer....thus the need for cell terminal covers. A couple of students took it upon themselves to surprise me one day with their creation of a DIY vacuum forming machine.  Crude but effective, they are in the process of forming the needed 48 covers for our lithium cells.  We are using .62 thick thermoplastic from Professional Plastics, a vacuum form box made from 2x4's and a shop vac.  Works like a champ!

Spring break fun and sun?

  Well, normally, any right minded teen or teacher living in coastal North Carolina would have taken advantage of the beautiful weather during our recent spring break. You would think so....but not the Topsail Electric Vehicle Class! We worked Friday through Tuesday on the vehicles making changes and modifications needed to be ready to compete in the upcoming EV Challenge final event April 21-22.
  Up to eight team members showed up each day bright and early to help change out batteries, create new terminals, wire the BMS and remove a strut among other activities.  We had an epiphany of sorts when we looked at the calendar before srping break and relized that we only had 18 class periods before competition!  The students made a decision to dedicate a part of their vacation time to help work on the car and truck to insure that we are ready for competition.  Dedication and preparation breeds success.

BMS Wiring aplenty

We are trudging our way through the BMS wiring as you can see.  There are many wires that need to be terminated correctly and hidden as well as possible, since we always believe half the battle is aesthetics.  The cell level terminations are coming along nicely, but the wiring harness wiring is another story altogether.  We found that the wiring had been done "backwards" from the diagram, if that was not bad enough, during testing of the harnesses, a ground lead accidentally touched a high voltage lead causing quite a spark, so we are getting a new set of harnesses and connectors.  Lessons learned!

The BMS wiring has begun!

Well, it is finally time to begin the daunting task of wiring the Orion BMS in the MR2.  We took a while to figure out exactly how the wiring would have to be done including the routing of the wires from each cell back to the BMS.  Thanks to the excellent customer support of Andrew at Orion, he approved our wiring diagram, and away we went.
    The first hurdle was that the front battery box would have to be wired prior to installing into the car.  To accomplish this, we had to pre-wire it with a separate harness that could be plugged up when the box was back in the car.  In the pictures, you can see the students crimping each connector for the primary harness.  We are almost ready to wire the BMS harnesses.  What is really nice about this experience is how the students have stepped up to learn about the system and how the wiring process should be staged for completion.  After the wiring is complete, we will have a chance to test the harnesses prior to plugging them into the BMS.  Stay in tune, there is more to come!

Battery re-installation

After a two months of research and design.  Careful consideration has been put into the BMS system and wiring of the unit and and batteries.  We top balanced the 48 cells and let them stay wired in parallel over the last two months.  Now we are prepared to re-install the batteries and label them for the wiring of the Orion BMS.  We cleaned each cell, labelled them and installed them back into the battery boxes in the correct orientation.  Our next step is to carefully wire the harnesses for the BMS.

Charger relocation program!

We had always kept the Zivan NG-3 charger in the trunk, and this posed problems with heat, and aesthetics.  Plus, we never utilized the "gas" door location for the power plug during charging.  We now have relocated the charger in the engine bay away from the elements, freeing up the trunk area and now allowing for a neater install plus the ability to use the "gas" door for the charge port.  The charger will be integrated along with the BMS, with the BMS controlling the charger at all times.  This should be an interesting journey!

Always something!

     We came to class today only to find that our vehicle lift was sitting in a puddle of hydraulic fluid! The lift has a leaking seal on the hydraulic cylinder. This is a big issue because we can not lift our MR2 up to work on our BMS.   We are trying now to find a replacement lift(donation) or to get this one fixed.  It is an old lift and may have seen its' better days, so a replacement may be in order.
On the plus side our batteries have all stabilized to 3.37 volts after a long charge period, essentially pre-balancing our pack for when we install the BMS.  Of course, we need a lift to do so!  Always something.