I loaded 5.03 beta and gave field weakening a shot. Wow.
The geared hub motor is actually an inrunner and seemed to take very well to FW compared to some disappointing bench tests on a standard esk8 outrunner. I did two runs back to back on the same stretch. There is a flat stretch long enough to get to top speed, then a fairly steep hill climb.
My metr was mounted in a bad location so I didn’t get very good logs, but I’ll try again later and post some.
65 battery amps (two 13s4p batteries in parallel) and 70 motor amps on 15awg wire LOL
Run 1: 0A FW (base speed). 22mph top speed on the flat, 20mph up the hill.
Run 2: 30A FW. 27.5mph top speed on the flat, 22mph up the hill
Run 3: 40A FW. 29mph top speed on the flat
Uphill performance barely improved and this makes sense now that I think about it. Field weakening current takes from the maximum motor current pool so there isn’t much additional power available as most is being used to overdrive the motor.
The power requirements are enormous above base speed. It’s pretty much pegged at 50A cruising at 28mph, vs when it’s below base speed the amps vary depending on the load. That also meant that the controller hit 70C pretty quickly. Feature wise it would be nice if field weakening only worked when a button was being held. That would allow it to work as a sort of a temporary afterburner so you didn’t drain your battery and cook your windings.