Setup and monitoring app for the VEC500

[Jusp]

I have a 10kW (golden)motor controlled by a VEC500/48V built in my sailboat. This is running, but for some reason the VEC500 cuts off the motor under moderate load. I have a hefty LiFePo battery bank so there should be no reason for this. My hypothesis is that the VEC is still configured for lead batteries.

Trying to connect to he VEC500 with the USB cable, the PI-800 app refuses with an error "fail to open the serial port COM0, 9600"
I was able to establish this connection a long while ago, though after some trouble even then. It now completely refuses to connect.
Does anyone have suggestions here? Also, this app seems quite primitive. Are there better ones?

[Bikemad]

Hi Juul,

If the controller is losing all battery power when the motor cuts out, it could be the battery's BMS cutting the power off completely, this might also prevent the controller from emitting any error flashes/beeps.
If the BMS is cutting the power to the controller, it could be due to a single weak cell whose individual voltage is dropping below the BMS minimum safe cell voltage (typically 2.5V for LiFePO₄) causing the BMS to disconnect the power.

Are you able to immediately restart the motor using less throttle after the motor has cut out, or do you have to wait several minutes before it can be restarted again?

I think it is unlikely to be the battery settings as the default 48V settings (which are used for LiFePO₄, LiPo/LiIon and Lead Acid batteries) would only stop the motor working if the battery voltage dropped below 42V under load (which is 2.625V per cell for a 16S LiFePO₄ battery).

Could the motor or controller be getting to hot under moderate load causing the thermal protection to cut in?
11 regular flashes/beeps indicates the Controller is overheating or 13 regular flashes/beeps indicates Motor over-heat protection has been activated (Motor temperature is higher than default safe value).

Regarding the Programming problem, are you sure that COM0 is the correct port that your USB program lead is connected to?
Click on the dropdown menu button to see if other ports are available.

If you open device manager, you should be able to see which port the USB-SERIAL-CH340 is actually plugged into:



If USB-SERIAL-CH340 does not show up in device manager, it looks like your PC/laptop is not recognising it and you may need to install the CH340 driver before plugging in the USB programming lead.
The most recent version of the PI-800 program (v3.3.0.b150501) can be downloaded here.

Please let me know if any of this helps.

Alan
 

[Jusp]

Thanks for your answer Alan,

I am pretty (though not 100%) sure that it is the motor controller, not the battery controller, for the reason that I am able to reset this condition by quickly closing and opening the throttle. My BMS requires a hard reset.
Problem is that when this happens I typically am at the steer and do not have time for close investigation inside, more interested in either getting the motor to limp again or else raise the sail. I should round up a reliable crew and try force this condition in safer waters.

It could possibly be temperature, but my gut tells me that this is not the case. Various reasons, but the only warning from the motor controller I have ever heard is 16 beeps, which is not documented in the list that I pulled off the GM web site.

I will try the COM settings in the weekend, will let you know.

[Jusp]

Yup, it was the batteries. It appeared that 3 years after installation it became time to clean the copper contact plates connecting the lithium cells. Marine environment does that to you.
A trial clean of the worst offending cell seemed to solve my problems already, so I scheduled the other ones for later.

That said, the motor controller was not very informative. First, I already had set the low cutoff voltage to 30V a while ago, so I do not understand why it switched off when the battery voltage dropped to 50. Second, the amount of beeps after that was 14, undocumented in https://www.goldenmotor.com/controllers/GoldenMotor%20FOC%20Motor%20Controller%20Guide.pdf. To be sure, I forced this bailout condition a number of times and recounted. Same results, bailout at 50V, 14 beeps. What could be going on here?

[Bikemad]

I think the 14 beep error code occurs if the Throttle is not in the OFF (or Neutral) position when the controller is powered up, which could occur if the BMS momentarily disconnected power due to a perceived low cell voltage condition caused by a weak cell or poor cell connection.

I don't think the 50V battery voltage is responsible for your cutting out problem, it sounds like it was probably the voltage drop under load across the poor cell connection that was causing it.

If (under load) you had a 0.88V drop across a poor cell connection, the BMS would perceive a voltage of just 2.30V across the affected cell (instead of its true voltage of 3.18V) which should be low enough to trigger the low cell voltage protection within the BMS.

16 LiFePO₄ cells at 3.18V per cell under load = 50.88V, but the 0.88V drop across the resistance due to the the poor cell connection would result in a total battery voltage of just 50V.
Under a 50 Amp load, the additional resistance due to corrosion etc. of just 17.6 milliohms (0.0176 Ohms) would cause a voltage drop of 0.88V.

If the battery power is suddenly cut by the BMS while under load (which I would expect to be triggered by a perceived low cell voltage) the BMS monitored cell voltage would instantly rise back again, which could allow the BMS to automatically power the controller back up again while the throttle was still applied, which would explain the 14 beep error code.

Perhaps your BMS only requires a hard reset after a low battery voltage or excessive current condition, and it simply resets automatically after a triggered low cell voltage event when the cell voltage rises back up to an acceptable voltage. 

Alan
 

[Jusp]

That explanation makes a lot of sense. I already wonderered why the BMS had not reacted to the low voltage condition, but instead left it to the motor controller. But your scenario could very well be what was playing out. Anyway, I know a lot more now about my system, and can’t wait to try it out on the water (my experiments were in the dock). Unfortunalely we are having pretty bad weather these days in Monterey Bay, so that has to wait a while.

Thanks again, Alan, for helping me on my way.

Juul