BMW 3.0 CSE

The onboard charger and battery management system have been in the car for a while but until today I had no way of adding electricity to the car.  I bought a J1772 receptacle a while back but hadn't got around to fabricating a way to mount it to the car.  

Building a box to hold batteries sounds so simple.  It isn't. The batteries have been in and out of my front box many times now.  The latest reasons for disassembly were to relocate the BMS and plate the buss bars .  While plating, we decided to do the buss bars in Paul's car also since the battery box is out of the car while the car is being painted. My box on the left, Paul's on the right It is interesting to see the two approaches to battery fitment side by side.  Figuring out how to get 14 Tesla Model S battery modules fitted into a car designed for a gas engine and transmission is always the most difficult part of the EV conversion process.  The big rectangular batteries just don't want to fit into the curvy voids of a normal car body.

 My first attempt at programming a simulated analog gauge entirely via software was OK but didn't have parity with my digital version and was missing some features such as cruise control, warning icons, and power mode.  So I worked on it some more.

The Tesla batteries need to be wired up in series to get to the 350+ volts necessary to operate the Tesla drive unit.  This means connecting them all together, one by one.  This could be done with cables but they'd have to be big cables because the drive unit can draw up to 680 amps under full throttle.  Cables that large are hard to work with so a better alternative is copper buss bars. 

 My plan had been to mount the Battery Management System unit in the front battery box, in the void near the steering gearbox.  There is enough room and I had everything mounted when I realized there was a problem.  The Orion BMS 2 wiring manual clearly states: