Yet Another Fifteen Minutes of Fame

 In mid January, I was interviewed by revdup.life and the finished video and blog were posted in May.

We started in masks and quickly decided that it would be easier to understand if we dispensed with the face coverings. Revdup.life is telling the stories of people like myself who don't necessarily fit the stereotype of liberal tree-hugging green activists that are often associated with electric vehicles. While concern for Mother Earth certainly plays a role in the lives of many who advocate for clean electric vehicles, there is another group of people who don't just talk about it. We sweep out a corner of the garage and actually build something. And we discover the dirty little secret that the greenies can't comprehend: these things are FUN to drive!

I hope you enjoy this show and tell.

Brain Transplant

 

After the physical installation of the Scott Drive SD100, what remained was the configuration and customization. I had hoped that Jack Rickard had it dialed in with the correct parameters for the Siemens motor, but no ...

I found that while EV West no longer carried the Scott Drive controller, they still had the software and user manual available for download (they've since taken it down). I loaded the control software and established the communications link from my laptop computer to the controller. So far so good. Then I made the fatal mistake of updating the firmware. That locked the controller up tighter than a drum and broke the communication link. What now?

My friend Ed Clausen had successfully upgraded his BMW from its original DMOC to a Scott Drive, so we compared notes and figured I had uploaded incompatible firmware. He suggested that I contact Dr. Scott Osborne, the developer and principal of Scott Drive, directly for help.

Scott immediately surmised that I had overwritten an EEPROM on the system board. He could send me a new one, but for less than the price of shipping I could buy an EEPROM programmer and flash it myself and avoid transit time as well. Amazon delivered my new EEPROM programmer the next day and after a typically interesting time finding and downloading the associated software I climbed the steep learning curve to become a barely competent EEPROM programmer.

First I had to remove the top housing from the controller. Happily it was well designed for servicing and could be removed without uninstalling the whole controller.

Let there be no confusion over the fact that electric vehicles are actually just big computers with wheels attached. I still had an old chip puller from my IBM Systems Engineer days, so getting the chip out and flashed was no problem.

Scott sent a new level of firmware for my old controller and it updated successfully. When I started to set the configuration, it was clear that the values were way out of range and pretty much random. Scott offered to do a remote link to my laptop from New Zealand and he saw that there were some issues with the firmware, so we'd need to give it another try after he debugged some of the code. Scott had to set up an old controller to test his firmware changes, then sent a new file, set up another remote session and dialed in all the configuration values. A quick drive around the block confirmed it was working well. I'll be fine tuning things for a while, but first impressions are that the Scott Drive is smoother than the DMOC and seems at least as good in torque and regenerative braking. I'll shoot a new drive around video, so stay tuned ...

I must say that Scott was very responsive, given the time zone thing. I've done remote support, but never from halfway around the world. He had every right to tell me to get lost since I bought a seven year old used product that is by now lacking the improvements in the current model, but he was very helpful, even spending weekend time to set up an old controller so he could test his changes to the firmware. Many thanks to Scott for excellent customer service, a real class act!

May 6 Update:

Today's ambient temperature was 86 degrees Fahrenheit (30C), so I ran some errands this afternoon totaling around 10 miles with two stops along the way. The internal temperature inside the car parked in the sunny parking lot reached 110 degrees (43.3C) so I'm guessing it was at least that under the hood. That would certainly put the old DMOC inverter into thermal limiting making me crawl home as a moving roadblock. Not so today! The Porsche ran the same throughout the trip which leads me to declare victory. Obviously I also need to do an extended run at highway speeds to verify, but I'm a happy camper. Still some fine tuning to do, but it looks like the Scott Drive has met my prime objective of making the Porsche a year round every day driver.

Heart Transplant

 If you've followed the evolution of the Porsche EV, you're probably aware of the cooling issues I had with the DMOC 645 inverter. Literally since day one, it would drastically limit current whenever the ambient temperature was over 90 degrees F, which is most of the summer and fall here in Austin. Winter and spring the car ran great, summer it was undriveable, moving away from stop lights at a snail's pace. I complained about it in my test drive video. Clip ends at around 12:02.

I've revamped the cooling system and added capacity on several occasions without success, and decided that if the car was to be a year round driver some drastic steps would be needed. After Jack Rickard passed away, I was randomly watching old EVTV videos and ran across one from 2014 where he was planning to test a brand new Scott Drive SD100 with a Siemens motor like mine, replacing the DMOC Inverter and GEVCU controller. Clip ends around 1:31:13.

Tagged and ready to ship from EVTV

After a little research on the Scott Drive, it looked like a nice replacement for my dodgy DMOC. It was developed and manufactured in New Zealand but EV parts dealers in the US didn't carry it. Guessing that the shipping on a new one from half a world away would be prohibitive, I got in touch with Richard Flentge of EVTV to see if the one from the video might be available. Sure enough, it turned up in the shop and after the exchange of a couple DC/DC Converters and some $$$, it was on my workbench in October, 2020. 

Scott Drive on my workbench

I got the old DMOC and GEVCU removed and started working on the physical mounting for the new controller. 5/8" marine plywood will give a solid but slightly compliant platform with room for terminal blocks. Paint it black and it will disappear. I also took the opportunity to remove a bunch of old wiring and generally tidy up the under hood area. I'm quite pleased with the result.

The Scott Drive is a handsome piece of technology and looks like it was custom painted to match my motor bay. Part of the beauty is the integrated precharge circuit and contactor much like the Soliton1 controller in my MG TD. With integrated control electronics both the GEVCU and precharge modules are eliminated which makes for a much cleaner installation. Next we'll set the configuration, and that's a whole new adventure continued in the next post ...