Thursday, January 26, 2012

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.

Thursday, January 19, 2012

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.

Tuesday, January 10, 2012

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.