openinverter forum

I have put a Leaf motor in my boat. It's an EM-57 with a gen 3 OI board.
The other day when we were out on a test run the motor suddenly stalled and I believe came to a complete stop. Boat still making some speed. After a little while it came on again. This repeated a few times until I made it back to berth. To make sure to have controlled starts I shut of the motor and restarted the rest of the times it happened.

Today we ran a few tests still tied to land. I suspected a few things about noise from pumps to bad throttle. But everything worked as good as one could expect. That led me to believe that it is happening when I am reaching the speed where I am not accelerating any more at a certain throttle position.Tied to dock we are constantly "accelerating" from a motor perspective. Does that make any sense?

What can I do to confirm this or what other tests can I run?

A couple of photos for attention:

Nice project Just a few ideas with my limited knowledge:
- Is there already a "boat mode" implemented? For car usage, the throttle is just giving a torque request, which leads to increasing rpm on an dry boat. As far as I know for boat a speed regulator would be normally used, to have a certain thottle position leading to a certain, regulated RPM.
- You could observe the spot values of the pot and the error information (lasterr), maybe this gives a hint what is going wrong.
- Maybe also a temperature issue or low voltage, should be visible in the spot values.

Thanks Uhi22,

I was thinking the same ways you are, regarding the differences between a car and a boat, at first. But then I was thinking about a sort of ideal case where a car is given a certain small amount of throttle on a long flat road. The car would accelerate to a certain point where all universe’s forces are at equilibrium, and the car would make constant speed. What is the big difference between that, ideal, case and my boat. Would the motor in the car suddenly want to stop when constant speed was achieved?

When it comes to temp and voltage I am fairly sure that is not the issue since we have about 390V in the batteries and the temperatures were constantly monitored @ about 20° to 30° (I am assuming Celsius).

I’ll run some more tests today as you suggest, logging throttle pot, rpm (speed), temperatures, status and lasterr.

Your example sounds plausible. I guess the difference is while accelerating. Giving full throttle at a car will just lead to high torque and a motor rpm linear with vehicle speed. At at boat, this will cause a lot of slip, maybe overturning the motor decreased accelerating. Of course, an experienced operator could compensate this lack, so No problem for some trials.

I know OI foc doesn't like fast spinup. There is a boat mode where throttle controls speed, currently not sure how to activate it... Check cruisemode or potmode