Grin Technologies intermittent sensored mode

[StCroixSpeed]

Hello,

I am a new eBike builder that recently completed my first system install. Having an issue with the controller intermittently switching from "sensored" mode to "un-sensored" mode (no hall sensor).

The drive system is entirely from Grin Technologies, purchased in late 2016:
35A Grin Sine wave controller
TCDM Direct Drive Hub motor with internal geared hub
12 magnet Grin PAS sensor
Cycle Analyst 3.1
Battery: Em3EV 50V 27AH 30Q battery
Bike: Surly Puglsey

During my first shakedown ride, I rode on a gravel road that had several pot holes. While I rode fairly slowly, the bike did get bounced around a bit. After this road, I noticed the more irregular operation and noticed the light on the controller blinking red, indicating a switch to un-sensored operation.

Typically when I turn on the controller the Hall sensors are active. Then as I ride down the road I will see my Speedometer reading go to zero "0", and the controller is blinking again. During a ride the system will switch back and forth between sensored/un-sensored mode sometimes several times in a 5 minute ride. The sensored mode is much smoother as one would expect.

I tried checking the voltage at the hall wiring connector but as soon as I start sticking the test meter into the connector the unit switches back to sensored operation.

For the experts on this forum which of the following areas are the highest potential to resolve the issue:

1. The Hall sensor connector
2. The Grin Sine wave controller
3. The Hall sensors in the TCDM Motor

Thank you for any and all suggestions.

Patrick R. McKellips

 

[amberwolf]

Connectors are always the first best place to look for a problem. Can be backed-out pins, bad crimps or solder, etc.

Or a wire could be broken at the back of the connector, or anywhere between the connector and whatever it connects to at the other end of the cable.

Wherever wires enter or exit things, there's a potential for bending/breaking, or where they solder to a part or a board, if you don't find a connector issue.

 

[StCroixSpeed]

Thanks amberwolf for your suggestion. I believe you are right on the money.

Justin from Grin responded right away to my email. Love their service! Here is what he said:

Hey Patrick, odds are almost for sure that this is a result of an intermittent contact at the actual connector plug itself, and quite often the use of dieletric grease on contacts with low pin retention springs can result in a more intermittent contact than not using it. What I would try doing next just to confirm this is snipping off the JST hall plug and hard wiring the 5 signal lines together (either soldering or crimping) to confirm that it stays 100% sensored all the time then, and if so we can then work with you on a suitable replacement plug. Normally the JST-SM's are pretty reliable but there are other waterproof connector series that can be better for off road riding.

If it still occurs even with the jst plug eliminated, then we can further troubleshoot if this intermittency is inside the hub or the controller and work out a solution accordingly.

-Justin