Found a second broken spoke on that wheel, a few counterclockwise away from it on the inboard side (instead of the outboard side the first one I saw is on), and looking at other spokes found some in the same area that look bent as if something (stick?) got stuck in the spokes.

Don't know what, as there's no visible bits left behind, but it could've even been a stick the dogs had been chewing on and left leaning against the wheel, then when I rode off to work it fell into the spokes and snapped, but damaged the spokes at the same time.
The motors make such a loud hammering with these Grinfineons in the sensorless trapezoidal mode when trying to startup from a stop I wouldn't likely notice the sound of a stick (even a hefty one) breaking, or spokes snapping, especially with all the dogs around the trike being all excited and playful like they usually are when I'm leaving or coming home.
So I gotta check all the spokes and replace at least those two.
I tipped the trike over on it's side to check out connectors and whatnot to see if something loose might be why the righthand controller keeps cutting out under load. Found no visible issues with anything, but went ahead and disconnected and replugged the PP45s on the battery connections anyway, several times each, just to "scrape off" any potential contamination I might not be able to see.
Powered the trike on, then tested the right motor (still offground, trike on it's side), it starts up and runs (but it would do that fine without a load anyway), but the left motor wouldn't do anything, no response to throttle at all. Since that controller's LED doesn't light up or blink (though it's supposed to in sensorless mode, like the other one does), I can't tell if it's on or not, so I pushed the button switch on it's endcap, to no avail. Repushed it to put it back in teh state it was in before (which should've already been "on"), no change.
Verified it was plugged into the battery connection, dug out the voltmeter, and verified power at the back of it's PP45s ok, same voltage as at the ones on the other controller. Checked and found no 5v at the throttle power wire at the controller's JST (also none at the red wire of the ebrake connector). Then powered the trike off and disconnected it from all the phase and control (throttle, ebrake, etc) wires, leaving only battery power, and powered the trike on, and verified still no 5v, regardless of switch state.
So the non-cutting-out controller just died, for no reason I could see.
I took it off the trike, and brought it inside to open it up and verify things like battery and LVPS voltages.
First thing to note is that the wire to the LED was broken at the back of the LED, held on (barely) by the white (silicone?) that secures the LED to the case end plate. Explains why I didn't always get a light on this one when it's on.
Next, I found the switching LVPS had only around 8v at the input to the 78L05, but it's marked on the PCB that it's supposed to be 15v, so either the 5v supply is being dragged down by something else that's fried inside, or the LVPS 15v is being dragged down by a dead 78L05.
I closely examined with a magnifying glass for solder bits, corrosion, or anything else that might potentially cause this sort of thing, and found nothing. But when examining the JST connectors, something bugged me about them, so I took the other controller off the trike and brought it in, to compare them, and found that the ebrake connectors are wired opposite from each other. That's wierd.
I didn't see this before because this controller's connectors do have the (labelled) heatshrink on them from the back end of the JST over the cable (unlike the other controller); I only saw it now because I had to pull it back to check for problems like stray wires at the back of the JST.
I don't know which one is correct, and which one is wrong, but because I have them wired in parallel to the same ebrake lever, it means that effectively the one on this controller ends up having it's 5v line shorted to the ground on the other controller every time ebrake is engaged.
That completely explains the wrong behavior I first saw under the first testing of these controllers back in August, where this controller simply appears to shutdown whenever the ebrake was engaged, letting the wheel just spin down, instead of stopping it's rotation like the other controller does.
Another thing I noticed when testing on the bench today is that the Turnigy Wattmeter I have on the test battery showed an idle current of 50-60mA for this controller. The other controller, plugged in in place of this one, only has an idle current of less than 10mA (TWM flickers 0.00-0.01A, mostly staying at zero). So this (non-working) controller has at least 5-6 times the amount of current, and probably more like ten times, assuming the other one's current is less than half of 10mA based on the TWM's behavior).
Anyway, this controller will have to go back to Grin Tech now to get fixed, so now to write up an email to them.
So much for my plans to fix up the motor/controller setup on the trike to get the sinewave and prop-regen stuff all working. :/
I guess my next thing to do is to reconnectorize the old generic 15FET I'd had on the leftside motor to match the PP45s and the JSTs I've got on the trike's wiring harness now, so that I still have 2WD (necessary for the trike) once I get everything else done, while waiting for the controller repair/etc.
Then I take the left wheel off and fix the spoke problems.
Then I build that Stromer motor into one of the rims, to replace the rightside MXUS (because I don't have disc rotor mounts on that MXUS anymore, though I'm sure I can put them back on the cover one way or another, I want to try this motor out anyway).
Then I begin modifying the frame to mount the new AVID BB7 disc brakes on the rear wheels.

This is kind of a major undertaking, because I have to basically build a new side rail for each of the outboard sides, with a new (clamping) dropout on each side (there won't be enough axle length left for a nut), that has the tabs to bolt the disc brake caliper to.
This does give me the opportunity to also make the outboard side rail bolt on, instead of integral, so it'd be MUCH easier to take a wheel off without tipping the trike over on it's side for any work that I have to do on one. Have to do this to the triangulation supports from the dropout to the top rail too, so the side rail will have the whole thing be one piece, and four bolts plus the axle pinch bolt will take it off.
Ideally, I'll also be able to make a "parking brake" lever or whatever, that pulls and clamps the rear disc brakes on, probably with a second cable to each of the calipers, to replace the wheelchair-handbrakes I'm using for that now (which just friction against the tires themselves, and thus work better the more inflated the tires are, and worse the less they are...but either way are more and more difficult for me to set and release as my hand and arm problems get worse over time).
I can't actually make the disc brakes work as brakes yet, though, because I haven't found cable long enough to reach from the bars all the way back there (I found *housing* long enough...just not brake cable yet). EDIT: found some tandem cables that should reach, supposed to be here Monday.
After that, there's lots of other stuff I want to do, but I don't even know if I'll get all of the above done in the 5 days off I have left.