2nd Test Drive, the drive between houses
Working on the 320i unfortunately has taken a back seat to a lot of things going on in my life. The biggest of which is I sold the house I have lived in for the past 15 years and bought a new house. We started the house hunting process last fall and it seemed like every weekend until the snow started we were out looking at houses. Once the snow started I started my usual winter activity, skiing. We finally found the house we wanted and purchased it earlier this year. We had some renovations we wanted to make before we moved in and those took until May to be completed so we just moved into the new house last month. The garage still needs a lot of organization. I had to breakdown 3 years of all the systems, components and tools I had put together and have them moved to the new house. I am in the process of setting everything up. The only problem is the new house has a smaller basement, but larger bedrooms. I will have to setup part of my operation in one of the bedrooms that I will also use as an home office. The 320i is still in the garage at the old house and will have to be moved soon. I would love to drive it to the new house but the car has not been inspected. Massachusetts requires autos to be inspected every year. The 320i has not been inspected in three years so the inspection sticker is expired. For an old car like the 320i even if it had the ICE still in it they would not do an emission test. They mostly focus on the mechanical aspects of the car and for an old car they really look at everything. That is reason why the 320i does not have an current inspection sticker. Although it drives just fine there are still a couple of little things that need to be finished before it would pass inspection. All of those things could each take a weekend to complete. The vacuum power brakes are the biggest issue to resolve and were my biggest concern driving the car. I planned to drive the car early on a weekend day, so there would be less traffic.
First I had to charge the battery pack. For all the time since the first drive I was letting the pack sit at half charge. Every week or so I would turn the car on and spin the wheels for a couple of miles. That did not really take much out of the battery. I still was showing 35 amp hours out of 60. But before driving it on the road again I wanted to fully charge the pack. Even though the drive to the new house is only 16 miles, 4 of those miles are on the interstate and I wanted to get a good measure of the battery use. To start the charging I checked all the connections on the car and I turned it on to charge the 12V battery (from the DC/DC converter) to make sure all the relays would latch. I then plugged the Siemens EVSE into the 320i. I had a lot of problems with this EVSE - the first one I received would not even charge my Volt. The one now installed has been working for over a year charging my Volt every day and it worked the last time I charged the batteries on the 320i. But when I plugged it into the 320i, it initially came on but then shut off with an error. I repeated the connection an noticed the Brusa charger was also coming up with an error. Who was erroring out first? To find out I used the J1772 cable that I had connected a NEMA plug on the end so I could bypass the EVSE and directly connect the Brusa to the 240V source. When I did that the Brusa came right up so the Siemens must be the problem. I have one of those AVC2 modules installed for controlling the J1772 interface but the Siemens does not seem to work with that. I used the serial interface on the Brusa to monitor the charge and checked individual battery voltages. Everything appeared ok and I charged for three hours to put another 10KW into the battery pack. I checked every battery voltage and none deviated by more than 25mv so the batteries are still looking good. I took the car out for a spin around the neighborhood. The vacuum brakes still are not working and the vacuum pump runs a lot. Not as much as before, but after each brake application it runs for several minutes. I tested it and the reservoir starts to lose vacuum with just a small amount of pedal travel. The pedal has to move half way to the floor to get the car to stop so it completely depletes the reservoir. It might be possible the vacuum brake cylinder is not working or has a leak. That would be a pain to replace, the master cylinder would need to be removed, which means disconnecting the brake lines so the brake lines would require pressure bleeding again. The other problem is just finding a replacement vacuum brake cylinder. That part is not available from BMW or any auto parts online store. On eBay I found there are vacuum brake cylinders available for other early model BMWs so I ordered one to see if it would fit. It has to fit the master cylinder perfectly to work. The mounting bolts to the firewall could be modified it there is some discrepancy.
The day for the drive from Methuen to Andover could not have been better. Sunny and nice cool temperature for July. The drive went very well, even went on the interstate for a few miles. Very smooth and no vibrations. Just had to get use to the manual brakes, that will stop the car, but require some leg strength. I think on these old cars the brakes never worked like they do now. They did not stop on a dime and you had the anticipate stopping and giving enough room to brake. I started out driving in 3rd gear which gave really good pickup, but the motor/transmission really screamed a lot when the rpm got to above 3000. I will have to determine what is going on there. In forth gear the car drove very smooth, even on the highway at 65mph and 3500 rpm. When I finished the drive I checked the power usage. For the 14.5 mile drive the car used 4384W so that comes to 302W/mile which is a really good number and right on with the rule of thumb that the energy usage is the car weight divided by ten. The car weighs just over 2860 lbs and with me and a tool box another 185 lb for a total of 3045 lbs. With the full battery pack capacity of 27KW that would be 90 miles. But the full capacity would not be used often. Usually the 80% capacity of 21KW would give used which should give 70 miles range. That is a bit lower than my design goal of 100 miles. To get to that goal I would need over 30KW of battery capacity and that could only be achieved with the new CALIB CAM72 cells that are smaller and have more capacity. I cannot add more batteries as I am at the 400V limit of the inverter so I would have to replace the whole battery pack. That is not going to happen.
A video of this drive can be found here.