Archive for September 2010

Finishing touches

September 5, 2010

This weekend I finished up the last remaining battery box.  No more battery work (yeah!).  All 30 cells in the front pack now report to the BMS and have a full charge.  This took about four hours of work.

Three of the batteries in the front pack were dead and had to be replaced.  This meant removing the battery box which was pretty simple.  Two of the dead cells were at the end of a row, so it was easy to tap the whole row out, replace the two bad ones and tap all three back in as a block.  The other end with one bad cell wasn’t so simple.  As I was pounding it out, the casing cracked and the fluid leaked out.  Fortunately, LiFePO4 batteries aren’t particularly poisonous and don’t contain acid, and the actual lithium package inside did not leak.  Once the pack was complete, I then had to wire and test the BMS boards.  Twenty-six had been working already, so it was fairly straightforward to insert four more.  Everything worked!

Last step was to fabricate the plastic cover and then re-insert the battery box.  This proved to be fairly awkward, but I did finally get it done.  Here is how the finished product looks:

Front Box with Cover

Next thing to do was fix the rattling shifter.  The rattle was caused by a $3 plastic bushing on the shift rod that was broken in half.  This let the metal shift rod bang against the metal guide, making quite a racket.  It took me almost five hours of incredibly dirty and frustrating work to remove the shifter, take off the broken bushing, replace it, and re-install the shift rod.  VW mechanics sure earn their money if they have to do this job often!

This morning, I reconnected everything and we drove off with a full charge on 90 working batteries, and a nice quiet shifter!

Two things remain and the car will be 100% finished: BMS troubleshooting (one of the rear banks is reporting a fault) and installing a heater.  I can also mess around trying to make a Bluetooth connection from the BMS to my Droid phone – but that’s just for grins.  So close…