Okay, time for another update. I've been trying to push multiple fronts simultaneously so I can hop from one task to another when I get stuck or tired of working on any one thing.
The economizer board I designed seems to work great. Apparently I picked the wrong footprint for the resistor, but thankfully it wasn't off by much and I was able to make it work by bending the leads a bit. The contactors stay nice and cool now!
I've been revisiting the placement of the motor and in light of the projected cost of building a custom reducer box, plus having another driveshaft made, I thought I should try harder to see if I could fit the motor in the back with an IRS setup. It's taken quite a few iterations but I think it is possible. I had to go back to the textbooks I bought on suspension design and make sure the geometry would work out (both on its own right and relative to the front suspension geometry). I think I have it in a pretty good place now. The motor is offset to the passenger side a bit, which is fine because it will help offset my own weight. I still need to add some tubes for bracing and to support the coilover, but so far so good. Losing the solid axle will save me 135 lbs plus whatever the driveshaft weighs (probably 50 lbs?), while adding back the weight of the CV axles, uprights, wheel bearings and wishbones. Lower wishbones est weight is about 3 lbs, uprights would be 2.5 if made from 6061. Not sure about the other components, but certainly the difference in unsprung weight would be huge. It would also free up space in the tunnel to run the power and coolant lines, as well as maybe some electronics (dc/dc converter?).
For cooling, I found an electric water pump out of a Prius, which seems to be a common choice. I don't think I want to try splitting the flow between the motor/inverter and batteries, so I'm looking at connecting them in series on one big loop. The BMS will be reading battery temp directly and I think I can get motor/inverter temp through CANBUS, but I think it would also be wise to install a flow switch or something, so if the pump fails or there's a blockage I will know about it right away. I also need to figure out a way to control the electric rad fan. A simple fan switch in the coolant would be awesome, but I can't seem to find one with a suitably low 'on' temperature. Being made for ICE engines they are all 160*F or more. Even the digital adjustable controllers don't seem to adjust low enough, and the ones that do use a radiator probe that you shove into the fins, and I don't think I'm a fan of that. Any suggestions would be appreciated.
I got my hands on a used GE Wattstation EVSE, my goodness this thing is huge! I thought it was interesting that the control board has an ethernet port and multiple serial ports.. Apparently they were made to be expandable so you could connect card readers and bill people for usage if you mount it in a public space. It's only rated for around 7kW but that's still way more than I need.
I also got my MCU talking to my laptop and the Dilithium touchscreen. It can't really do much until it's connected to a few more things, but it was still encouraging to see. I also started on an overall wiring diagram and it's getting very complicated. Lots of details to work out there.
And finally, while playing with the Leaf reducer housings I 'did a stupid' and tried to reinstall the jackshaft without first removing the grounding brush. Result: broken grounding brush. Looks like a replacement from Nissan is >$125 which seems like utter insanity to me. After searching around on my own I wasn't able to find any similar brushes. Thankfully, I eventually found a local brush supplier (carbonbrushes.ca). I had a great conversation with the owner Dan, and he found me something that should be a direct fit. I had no idea brush selection could be so complicated, but there are apparently many different materials and characteristics, so I'm glad I was able to talk through the application with him and make sure the replacement brush would live up to its task.
I think that's all for now. I have decided not to race the car for the rest of the season, so as soon as I can clear space in my garage, I will be pulling the car in and removing the ICE components. Currently my side of the garage is full of the vinyl plank flooring I am using to replace the carpet on the top floor of the house, and all that has to be done before the baby comes in October. I'm about halfway done at the moment (two rooms and the stairs done, two rooms and a hallway left). Busy busy!