Running Sensorless with Amazon Brushless Motor Controller - Throttle Shutoff Issues

[Powahwheels]

Hi,

I am fairly new to the world of brushless motor controllers. I recently purchased a 1000w brushless motor controller from Amazon. I wired it up with a sensored motor and it seemed to work just fine. When I tried to use it with a sensorless motor, the controller generally works at very low throttle inputs but shuts off randomly. Sometimes it will shutoff after a few seconds at 1/4 throttle and sometimes it will let me go 10+ seconds on full throttle. The only way to get the controller back is to cycle the power switch line.
I put the controller in the low gear mode and it seemed to help but the issues still remain.

I am using a Ryobi 40V battery as the power source but I don't think it's a battery issue since I can run a sensored verison of the motor with no shutoffs. And, the battery should give me an overcurrent notification on the fuel gauge if it is tripping that. Any ideas?

Link; https://www.amazon.com/dp/B07JJX5PNW?psc=1&ref=ppx_yo2ov_dt_b_product_details

 

[E-HP]

I am using a Ryobi 40V battery as the power source but I don't think it's a battery issue since I can run a sensored verison of the motor with no shutoffs. And, the battery should give me an overcurrent notification on the fuel gauge if it is tripping that. Any ideas?

how many packs? one isn't enough to provide 38A

 

[amberwolf]

The sensorless mode may use more power trying to correctly drive the motor under enough of a load (because some controllers aren't very good at detecting motor position without hall sensors to do it for them), causing more battery voltage sag.

With a voltmeter or wattmeter / coulometer on the battery + and - at the controller input, what voltage do you see at the moment it shuts off, and what does it climb or drop to after shut off?

If the controller has a display, and the display does not turn off at shutdown, then the battery itself is not shutting off, which means the controller is doing so probably due to the above.

A number of dual-voltage controllers "autodetect" the battery voltage at power on. If the voltage is close to the midpoint of those two (about 42v in this case), it could pick either one. If it picks the higher voltage but the battery is the lower voltage, then the controller can shutdown under almost any load because the voltage will sag under load below the controller's LVC (shutdown voltage).


Also note that even without the "wrong LVC" problem, if the battery voltage drops below the LVC under load due to voltage sag (usually from excessive current draw vs the pack's capabilities, even if it doesn't trigger any pack internal protections), the same problem occurs--controller shutdown to protect the battery.