Welcome to this sub forum.
I am Electrical Engineer also.
I own 3 ebikes, I commute 330 days /year at minimum including subzero winter and rain on ebikes, mostly E+ and TForce/20,509km as of this moment/.
I own 3 ebikes including legendary Tidal fORCE and E+ bikes.
Do you want reliable quality US-built ebike for regular commuting or rather occasional ride?
I understand as an engineer you want complete, weather-proof, energy efficient ride , not patched-up, rolling experiment ,low tech ride.
Read no farhter if you DON`T want hub motor , rather bottom bracket type.
I encourage you to read posts about E+ on this forum, visit web site.
NMH battery spoils E+ bike what is otherwise wonderfully efficient, high tech, rock solid bult ebike.
You want to build from components, well, bigger component - motor if you want
built-in-motor-electronics technology is simply not available to buy because they comes with ready kits like E+, BIONX.
You cannot buid motor yourself.
China-brands if you don`t get frustriated dealing with them as an engineer offer undersized wires/you don`t want to waste power/, external controllers, low efficeincy,everything exposed to weather BUT CHEAP.
I respect Justin from ebikes.ca and appreciate his customer service.
His Cycle Analist is excellent design.
However he faces hudge struggle to make it right on Chinese brand components. Struggle with rusting inside motors, undersized wires, falling of pole magnets, brittle plastic, wire isolation cut by sharp entry into motor.
QC in China facory unlike in USA is hit and miss thing or not there at all.
As I said you have to start with efficent, built with quality material like bearings, magnets motor, no matter what electronics you add to power it if you have crude mechanical design with shoddy magnets and bearings, etc. - you will not achive much.
everthing starts with motor which must be designed with extensive modeling in right equipped lab to get it efficient.
If you have a look at E+, NMH 30 cell battery of this bike completely ruin perfectly good , wonderful drive, efficient, built like tank and light with US quality materials.
/just imagine it can draw just above 1000W-1050W at sustained 45km/h and that's peek draw, usually 950W at that speed/ - it says a lot about efficiency of E+. 9 power levels are NOT gimmics, they are well designed. E+ is wondeful exercise machine which just love love to be pedalled.
Again it takes 5 hours to fully charge its Nickel battery including 1 hour balancing stage - that's radiculous. Tech mind tells you that it must be a way to power E+ on 3-party battery.
Shortly, I am looking for technical partner , electrical person ,engineer ,E+ owner to work on this.