Update: I went out and bought me the cheapest, unloved, high mileage (170,000 miles) beat-up Gen 1 (2006 Highlander) available. The worst part is the dude that sold it, had it 'detailed' and it now reeks of carpet cleaning fragrance. I was really hoping for a Gen2 (2008-2009) but for a car I may end up destroying, this fit the bill. Everything drive train related works, much of the accessories don't, and I'm pretty sure there the door is glued together with silicone and it's airbags are missing. This will serve it's purpose as my test bench.
I've spent days reading threads going back to 2019, and tried to pickup how the GX450h and Prius Gen3 inverters have been reversed engineered (thankfully open sourced this time), and the how subsequent controllers were developed. I'm now up to the Zombie VCU which seems like the future in Toyota inverter controllers.
There is so much more to do and a growing list of questions and problems that I hope there are answers and solutions to. Otherwise, I will take what I learn and share my experiences with the hive mind.
Questions:
1. Determine what speed/power/efficiencies are possible with modified P310 transaxle.
a. Unlike the popular GX 'gearbox' there isn't a shiftable gear in the P310. I'm not sure how that will limit the available output over typical vehicle speeds.
b. Locking the P310 input to use MG1 for wheel drive possible? I haven't been able to find the gear ratios beyond trying to read a yellow label from a freezed frame in a Webber state video. Locking the input, will drive MG1 to wheel speed at a fixed ratio, like MG2. Not sure how that will limit anything. It might be possible to lock the P310 input my locking the outside of the clutch to a bracket mounted on the bottom of the transaxle housing, at least temporarily. I'm lazy and I don't want to pull the engine out quite yet. This would allow me to put the car on a lift (or cinder blocks) and experiment.
c. How does the oil pump circuit function? What what I can see there is both a oil pump run by ICE output and external oil pump. Not sure if it's cooled.
d. Additional cooling needed.
2. Determine what is required to reused an unmodified Highlander inverter (partial or full). MG1, MG2, MGR, DC/DC, Boost Converter, AC, etc
a. Can the Highlander inverter 3 MGs be controlled/reported via sync serial (MTH HTM CLK REQ)? It sounds like the frames are a different length than the other inverters, a Rav4 inverter was mentioned but I don't know if the data was mapped. Acquire hardware for spying on MTH HTM.
b. Are the other functions of the inverter controllable/useable? Are they independent of external control? Do they need to be powered from the Boost Converter?
c. What is the power rating of the Boost Converter? It may be different than the GX450h because it would also drive MGR, in addition to similar size MG2. It was never intended to power MG1+MG2+MGR so a direct battery connection to the DC bus will be needed to get full power.
d. Additional cooling for Inverter power electronics.
3. Additional/Replacement batteries and external charging. Location(s), Voltages, Capacities. Not on the top of my priorities, unless it seems impractical to convert to EV in which case they may be another HEV to PHEV project. With the ICE and gas removed there would be more room, but
Tasks:
1. Capture MTH HTM data for Highlander Inverter.
a. Acquire hardware to capture Sync Serial. I may open another thread for this topic as this should apply to any toyota/lexus inverter which communicates via sync serial. It's currently unclear to me if the VCUs including the Zombie VCU could/should used for this considering they have the hardware or if I should pickup a Due or maybe EVTVDue based board and added a quad CAN controller much like xp766 did. hilux_hx seems to have a pricey looking logic analyzer for this task? Amazingly, all the important drivetrain wiring comes back to the Hybrid ECU located behind the glovebox, I don't even need a screw drive to hack into this car. I've purchased a salvaged OEM Hyrbid ECU with including wiring harness which I can use to make a breakout\intercept cable, this way the original parts are left in tack for my experimenting.
https://openinverter.org/forum/viewtopic.php?f=14&t=205
b. Analyze frames. Compare to other inverters.
c. Control Highlander Inverter over Sync Serial, preferably with modified Open Inverter VCU.
d. Profit... by that I mean start a new expensive hobby which consumes all my free time.