Still Not Rolling Yet
You would think over the last four months I would have gotten enough things done to get at least the wheels spinning. Well the car and electronics are not quite there. I was able to get the Siemens motor mounted back in the engine bay and connected to the transmission. But that, just as everything else took way longer to complete. The main problem was that the BMW motor mounts that I planned to use did not work once the motor weight was loaded on them. They did not work because of the design of the main bracket for the Siemens. Because the Siemens motor mounts are on the front of the motor the mounting bracket essentially cantilevered off of the motor mount points in the engine bay. The problem with the BMW motor mounts is that they are designed for compressive loads, not tensile loads. When I put the weight of the Siemens on the bracket, the rubber in the BMW mounts stretched and the motor dipped down 2 inches so that the motor was resting on the cross member. I had to design new hard mounts out of aluminum block. That took several weeks to get machined, but worked out very well.
I also got all the water cooling lines connected and leak checked. I connected the Siemens to the Delphi DC/DC converter as one cooling loop. The DMOC will have its own cooling loop because the inverter is much more susceptible to heat than the motor or the Delphi. I did have a problem with the water pumps though. The way I had the pumps mounted the impeller was on the bottom, facing down. When the pumps were first tested and did not work well is when I discovered that they can be mounted in any orientation, except with the impeller down. So I had the disconnect the pumps and flip them 180 degrees and remount to the frame of the car. I guess one of the pumps did not like being inverted and would not pump after remounting in the correct position. I had to buy another Laing DC5 pump to replace that pump - a costly mistake.
The GEVCU I modified to drive my instrument cluster, which I call LEVID was tested and worked very well. LEVID stands for Legacy Electric Vehicle Instrument Driver. I modified a GEVCU so I could mount a daughter board that had isolation for serial and I2C communication. The serial interface is used to drive the 4-digit 7-segment display that is mounted in the middle of the tachometer on my instrument cluster. That display will be used to show a digital value of the numbers being set on the analog gauges that is selectable. The I2C interface is for a Real Time Clock (RTC) that is read and used as to display the time as another message on the 7-segment display. I programmed a 2nd GEVCU with a program that simulates the CAN messages that the DMOC and BMS will send during the operation of the vehicle and tested the LEVID driving the gauges. I had to build a wiring harness to connect the LEVID to the instrument cluster. Everything looked really good. Next step is to mount the LEVID in an enclosure and put the instrument cluster back in the dash. Speaking of which the dashboard is in bad shape. When I first got the car there was a straightened paper clip stuck in the side of the hazard warning switch. When I pulled the wire out the hazard flashers turned on. When I pressed the button it did not stay in and the flashers continued to flash. The wire was there to keep the switch in the off position. Unfortunately to replace it required taking the whole dashboard apart which I did. I also had to drill a 1" hole in the dash to mount the emergency off switch for the electrical drive system. The dashboard along with the instrument cluster still have to be installed.
One of the issues I have is where the 320i is located in the garage with respect to where my EVSE (charging station) is located. I had originally mounted the EVSE near the door leading to the garage as that was the shortest run for a cable conduit to the breaker panel and the Leaf I was leasing had the J1772 charge port on the front of the car. The problem is with location of the 320i. The charge port for the 320i is diagonally across the garage from the EVSE. That distance is longer than the cord on the EVSE, so I decided to make a new conduit run to the opposite corner of the garage. Forty feet of conduit and 50 feet of wire was tough to pull. I plan to get a new EVSE, a unit from Siemens that EV West sells (click here). That will be an upgrade over the EVSE that I have now and will also be able to do 7.6KW charging (but not on this build, at least not now, the 320i has a 3.3KW charger). The Siemens can be set for any charge level and it has a timer for delaying the charging
I got the front battery box installed, the batteries installed and all of the battery cables connected. All but one. When I changed the location of the maintenance switch to be on top of the plexiglass isolation, I had to make a new cable run that would go from the switch to the contactor box. I thought I had measured that correctly but when I went to connect the cable connector to the stud on the maintenance switch the cable was too short - about 1" short. This was the last connection to complete the battery circuit and is required to be able to charge the pack. The two options I have is to make a new cable or make a standoff. Both will take about the same amount of time because I do not have any cable connectors or heat shrink so I would have to order those supplies. Having the standoff machined will take at least a week, but I would not have to take the contactor box apart, which is my preference. Once I get that standoff machined and installed I should be able to charge the battery pack and then get the wheels spinning.
A video of all this fun can be found here.
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