openinverter forum

We have a jet boat powered by the Niassan Leaf 2 gen motor, inverter, charger, and 24KWt battery. The whole system runs from ZombieVerter on my own PCB design, with the latest firmware downloaded from GitHub.
If the motor is disconnected from the jet, it can reach 10.5K revs without any problem. But connected to the jet on the water, it is limited to about 2500 revs, and from about 2300 revs it starts wobbling.
I wonder what is causing the problem? My vision is that the water is not providing enough load or unbalanced coupler to the jet.
What do you think?
The motor is connected to the jet through the cardan, about 30cm long.

Post your params so we can see what you have configured.

Also it would be good to get logs of the CAN and some spot values like:
-Potnom
-Speed
-UDC
-Amps
-Temps

On top of Tom's ask, is it a single cardan joint? What's the angle it's running at?

jrbe wrote: ↑Mon May 26, 2025 3:47 pm On top of Tom's ask, is it a single cardan joint? What's the angle it's running at?

It has two cardan joints, each end of the shaft. It has no angle between the jet and the motor, and about 5 degrees between the whole system to the floor

tom91 wrote: ↑Mon May 26, 2025 2:54 pm Post your params so we can see what you have configured.

Also it would be good to get logs of the CAN and some spot values like:
-Potnom
-Speed
-UDC
-Amps
-Temps

The boat is stored far from my current location, but I have a few logs with some parameters.
I've configured just the pots parameters, udcmin=330 and switched CAN bus and Leaf units, car set to none.
The temperature was about 15-16 Celsius. I've started from 2 pots, tried 1 and had 100 revs higher, but wobbling as well.

Can you log the normal CAN? I need to see all the traffic.

Again I need the full param set.

It will take some time, dry weather is needed and a time to drop the boat into the river.

tom91 wrote: ↑Tue May 27, 2025 7:38 am Can you log the normal CAN? I need to see all the traffic.

Again I need the full param set.

Here they are

Joint been balanced. Today we have a ride on the river, not much changed, same shaking/limitation around 2300 revs. Rotation by hand not a problem

vitecd wrote: ↑Wed Jun 25, 2025 5:27 am Joint been balanced. Today we have a ride on the river, not much changed, same shaking/limitation around 2300 revs. Rotation by hand not a problem

-How have you implementes the motor side driveshaft flange?
-Support bearings?
-Have you aligned the forks of the driveshaft?

I used part of the original reducer, but there was only one gear left. A hole was made, and a shaft was extended.

Without Jet connected, the motor is doing 10000 revs smoothly.

Not sure if it's meaning anything
revs .05 scale, 2300 max

We will need logs of Potnom from zombie will doing this, there may be things limiting the torque request as its not flat out.

Edit your issue is: "udcmin": 360

This is limiting throttle, this should be shown by zombieverter and the potnom spotvalue

This is high for a 96s battery, change it to like 3.2 x 96 = 307V

Sorry, does not make sense to me. Could you explain, please?
The current voltage at the time was 380V
Without Jet, the motor spins 10000revs easily and smoothly.

vitecd wrote: ↑Thu Jun 26, 2025 2:34 am Without Jet, the motor spins 10000revs easily and smoothly.

Without load vs with load

Your CAN logs show the battery sagging down and thus the udcmin limiter kicking in, it kicks in before hitting udcmin as not to have an abrupt stop of of torque