Hi guys, been on a hiatus with internet forums since I got told to tig weld something mundane on a MIG welding forum...
Anyhow, since I snapped my 2wd ebike in half doing some urban moto x I found I hardly use my sensible dyu d1 as it feels SO slow now and I use my car instead. So having promised myself I wouldn't mess with the dyu, I took it apart and ordered a 6fet sensorless 4110 controller from em3ev. It runs 15s (62v max) 30a phase current 10a rated current which I set in the em3ev software. Originally dyu ran 10s 42v max rated current 7a, max current 12a, read from label on oem controller. Wheel motor says 36v 350w and has no hall sensors.
The Problem; at around 60% or more of max speed unless you accelerate gently you get a sudden grinding noise and feel from the motor as if all 3 phases had been shorted (don't ask how I know). Back off a bit and it gets better/goes completely. The strange thing is full throttle is flawless up to 60% speed and also if you gently accelerate around this issue you can load the motor up again and it acts fine. Once you get past the issue you can maintain speed up a hill that would be = amp loading to the rate of acceleration that would cause the grinding and not have any problem.
Also worth mentioning is when the controller came it was set to 70a phase 30a rated current. May have forgotten to adjust this down on 1st test ride
I have no idea frankly whats wrong and could live with it if I had to but would be really grateful if anyone knows what this could be and how to fix it. Thanks