2018 Radrover 750 upgrade

[NBD925]

Hello, I have two 2018 Radrover E-bikes, Identical.  I purchased a Bafang (RM G060.750.D) 750 Watt Motor for one of my 2018 Radrovers.  I installed the motor and everything fit and seemed to install great.  The problem is the 750 motor is not working with this stock bike.  The throttle works perfectly but when pedaled, the motor only works for a second and turns off.  Randomly it works for a few pedal strokes then goes back to not working unless you stop the bike, then start pedaling again.  Then it only works for a small burst and cuts out. 

Because I have an identical bike to experiment with, I swapped every electrical component one piece at a time from my working 2018 Radrover over to this bike with the new 750 Watt motor.  First the PAS Sensor, then the Controller, next the main wire harness, then the display.  The last test was to swap the rear wheels.  One with the stock motor and the other the new 750 watt motor.  The problem swapped to the other bike when the hub and rear wheel with the new 750 motor were put into the known good bike.  The same cutting out problems transferred over to the original bike that was working perfect.

I have tested everything. What is going on here?  Why is this new 750 motor showing these symptoms.  I am a full time mechanic so I can do some advanced trouble shooting if need be.  Can anyone help me.

Is there a testing procedure to test this Bafang 750 Motor, to check that its good.  I was thinking it could be a hall sensor in the motor that might be bad or intermittent.  The throttle and walk mode work perfectly.  The PAS sensor has been adjusted close and the book standard away from the magnet ring.  As I mentioned before, the controller and PAS sensor have been swapped with known good ones.  Actually every electrical component.  It is something in this motor.   

Will this 750 watt bafang motor work with the 2018 Radrover?

[NBD925]

Update:

Here are my new findings.  I swapped batteries again, fully charged, no change. Still had the motor cut out.

I was wondering why randomly the bike would start working correctly.  Usually after a battery tray wire disconnect.  Like when your swapping battery trays.  I thought it was from waiting a period of time but now I have it narrowed down to disconnecting and re-connecting the battery plug coming from the battery tray to the controller.  That has some sort of reset effect on the bike Controller. 

Once I pull that battery plug apart and reconnect, the bike works for a period of time, so far up to about 3:00 minutes perfectly. Then it cuts out and only allows small bursts for about 1 second after the wheel has been stopped. 

I don't understand why but it must have an affect on the controller. 

My questions:  Were there different amp rated controllers that Rad used in these Radrover bikes?  I thought I had seen reference to 22 amp stock Radrover controllers mentioned online (or something close) Does anyone know if Rad supplied bikes around this year vintage with different amp controllers.  It looks like these controllers are 16.5 amp max (stamped on a sticker on the back of the controller)

[Radding Along]

Motors are dumb. Controllers control the motor. Unfortunately you need a controller matched to the motor. That's the reason why a lot of people buy the stock part from the manufacturer. I feel for you, there are just so many tuning variables that go into the motor/controller combination.

I believe Rad has the motor in stock. I think I read it's around $360.

[rjp]

I have spent a lot of time reading about the up grades for power products from Bolton ebikes , now called Area 51. Seems to me that I read That changing the motor alone won't work without changing the controller along with the 750 motor. You can just change the controller and screen and that will work. But if you change the motor you also need to change the controller and screen also for it to work correctly.       

[JimInPT]

I have spent a lot of time reading about the up grades for power products from Bolton ebikes , now called Area 51. Seems to me that I read That changing the motor alone won't work without changing the controller along with the 750 motor. You can just change the controller and screen and that will work. But if you change the motor you also need to change the controller and screen also for it to work correctly.     

Yes, that's true; if you just swap the motor, the stock controller still limits the maximum power output, so you'd gain nothing.

But in addition, Altema (here on the forum) specifically set out to burn out one of the stock 750w motors (he'd replaced it) with the Bolton 35A upgrade and was unable to do it under heavy load and current for a long time.  The stock motor is apparently a lot tougher than one might think, so I don't see any point in swapping in a "bigger" motor unless you're taking drivetrain upgrades to an extreme or push the motor to its limits on a regular basis.