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.

Balancing act

We have removed all 48 cells from the MR2 and have wired them in parallel for a balance charge.  As you can see in the picture, we have set the voltage to 3.6 volts and will be monitoring the current as they charge.  As they charge, the current will slowly get close to zero until they are balanced.  No telling how long this will take, but we will be baby sitting for as long as it takes.

Our BMS has arrived!

Our BMS arrived last Friday and needless to say, we are overwhelmed.  The MR2 has to be totally rewired top to bottom to accomodate the new component.  The BMS will monitor all cells during charge and under driving conditions, giving us real time analysis of the Lithium batteries.  This technology will help preserve the lifespan batteries and help to keep them a balanced set.  The performance of the MR2 should be more consistent and we will have the opportunity to data  log our charge and discharge cycles.  Two students are working on a program that will create an interface that incorporates both the Synkromotive controller and the BMS parameters on the same in dash display.
  Today, we began removing all of the Thundersky batteries so we can top balance the entire set in parallel.  By doing this, we will have a balanced pack, and the BMS will have an easier job for the initial few charge cycles.