Vector 48v/500A and BLDC 10kW motor unexpectedly cuts out

[Danned]

hello

i have recently converted my sailboat to electric using the vector 500 controller on the GM brushless 10kw motor.

as a temp test using the pi-800 software I disabled the throttle voltage after first setting the max to 4.8 volts

all other settings are default

the motor at lower amp draw ( <2Kw ) seems fine but increasing isnt.

the motor cuts out after increasing the power, then I can reapply throttle and behaviour is the same. I get one beep on the cutout and no error codes.

setup is 8 x 6 volt golf cart batteries 220 amp hours
GM brushless 10Kw DC motor
GM vector 48v/500a controller
using bike throttle as a temp throttle until I get going

[Bikemad]

Hi Danned andto the forum.

What was the battery voltage and current draw immediately prior to the cutting out?

What diameter/pitch propeller are you using and is it direct drive or does it have any gear reduction?

What is the approximate size/weight of the boat?

It would be very helpful if you could also attach a copy of the .foc file exported from the PI-800 programming software (or post some screenshots of all your existing settings) as I don't know what the default setting for the VEC500 controller are. 

Alan
 

[Danned]

Thanks Alan, I appreciate the help. I am uploading to youtube some videos now and will post shortly. As an additional update, the same behaviour also exists when I run the motor at an even speed, for a while. I was able to repeat problem running at a constant 1Kw load, about 22 amps draw, battery at 47.4 volts. I cannot predict the time it cuts out, it seems random but no more than a few minutes before it cuts out as per the YouTube vids I just uploaded. It just cuts out faster if I keep increasing speed.

I also tried unplugging all wires, just had power and reverse hooked up.

battery voltage 47volts at cutout, 46.5 the lowest. They are brand new batteries.

Throttle has 4.3 volts across black and red, but seems that at about 1.7 volts is the highest I can get on the throttle before it cuts out.

I tried to do close to 2:1 gear reduction with the pulley system. It's about 1.92:1

35' sailboat, about 16000 lbs displacement, with I think 8 inch blade twin-prop - I don't know pitch but it's been on it for years - it likely is undersized

FOC attached

Video of Power Meter https://youtu.be/QTxhvsHrSDI
Video of Physical Setup https://youtu.be/lRp_zxFtDaI

[Rusina]

Hello,
I am NOT as specialist as Alan on these engines but I give you my experience if that can help you.
I also have this type of propulsion on my 7.5 ton boat, for 3 years.
I think your problem can come from 3 causes:
1) Propeller applying too much torque to the engine, which goes into safety.
2) Controller heating beyond the authorized margin, and safety,
3) Batteries descending beyond the service margin, but if they are new, it is unlikely.
To already eliminate the first hypothesis, you should know the torque applied to the propeller with the old heat engine and check if your 10 kW and your current reduction gives the same torque.
Since you have a pulley system, try a 4: 1 reduction, and tell us if your problem is the same, or if it improves things.
For the second cause, do you have the possibility of putting a thermal probe on the radiator of the controller?
No doubt a heat sink, which would limit the rise in temperature would improve this point.
Regards,
Paul.

Bonjour,
Je ne suis PAS aussi spécialiste qu'Alan sur ces moteurs mais je te donne mon expérience si cela peut t'aider.
J'ai aussi ce type de propulsion sur mon bateau de 7,5 tonnes, depuis 3 ans.
Je pense que ton problème peut venir de 3 causes :
1) Hélice applicant un couple trop important au moteur, qui se met en sécurité.
2) Controleur chauffant au delà de la marge autorisée, et mise en sécurité,
3) Batteries descendant au delà de la marge de service, mais si elle sont neuves, c'est peu probable.
Pour déjà éliminer la première hypothèse, il faudrait savoir le couple appliqué à l'hélice avec l'ancien moteur thermique et vérifier si ton 10 kW et ta réduction actuelle donne le même couple.
Puisque tu as un système à poulies, essaye avec une réduction de 4:1, et dis-nous si ton problème est le même, ou si cela améliore les choses.
Pour la deuxième cause, as-tu la possibilité de mettre une sonde thermique sur le radiateur du controleur?
Sans doute un dissipateur thermique, qui limiterait la montée en température améliorerait ce point.
Cordialement,
Paul.

EDIT: Google translation added.

[Bikemad]

Hi Dan,

I have just been watching your video where it cuts out at 46.9V while drawing a mere 33.7A (~1,580 Watts):



The motor doesn't appear to be overloaded in any way and I presume the single beep is exactly the same as the confirmation beep when you first power up the controller.

I suspect that the controller is simply rebooting itself, but I can't see anything obvious that would cause this to happen.

What happens if you twist the throttle quickly from zero rpm to full throttle rather than increasing it slowly?

It might be worth checking the 4.3 volts across black and red throttle wires to see if the voltage on the red wire is somehow being pulled low when the throttle is twisted.
I'm wondering whether the controller's +5V supply is somehow being pulled too low by the throttle and causing the cutting out problem.
If the main processor shared the same +5V supply, it might explain why the controller momentarily dies and then reboots when the throttle is released.

Here are your existing settings for others to look at more easily:



If anyone else can see something obvious that I have missed, please post a comment.

Do you know whether the throttle you are using is a Hall Sensor type or a Potentiometer (variable resistor) type?
It might be worth setting the Speed throttle type to 1:Potentiometer throttle to see if it makes any difference.

You might want to enable the Motor overtemperature protection and the Low voltage protection and also increase the Acceleration (rpm/s) to at least 600 (I don't know what the maximum available setting is) as an increase of just 200rpm every second seems to be very slow, as zero to maximum rpm would take over 20 seconds. 
I don't think this would be very safe if you needed maximum power to change direction in a hurry. 

Unfortunately, if it is not an incorrect parameter setting, or a throttle/wiring problem that can be easily sorted, then it might be a faulty controller. 

Alan
 

[Danned]

Thanks for the reply Paul! Very appreciated as I learn through this. Glad to hear that you have had good success with a similar setup.

1. torque: I am not certain I understand fully the implication of torque aside from using the analogy that running in 4th gear from the start is hard on any engine, if that is what you mean. If that is what you mean I think I understand why a larger gear ratio would help reduce this, it would translate in higher RPM for the motor and decrease the torque required to turn the prop shaft.

I also read up on torque as I think torque according to http://web.mit.edu/2.016/www/handouts/2005Reading10.pdf is defined as

5252 * HP / RPM (foot lbs) - so in comparing against the old Atomic 4 I had, here was my reasoning as I was leaving the shaft and prop the same, I tried to match up the electric motor in HP to the old Atomic 4 in HP. But you would be right that I was struggling with the gear ratio and took a guess at 2:1.

Thinking out loud: I think that old gas engines like the Atomic 4 only run at about 25% efficiency so that 30HP is probably more like 8HP at the shaft at peak RPM on the atomic 4. I used this to guess that the 10Kw motor should be fairly close to this in horsepower rating (maybe 6 to 13?). Given that the shaft and prop is the same, then the only difference would be that the electric motor is way more efficient and I should see an increase in power at lower RPM.

I would state that so far I think that in my limited tests, the GM 10Kw electric motor definitely seems to have more 'torque' at lower RPM. I can count the belt turns right now at 1Kw and it was about 180 RPM at the shaft, so my motor was only running at about 350 RPM. This is very slow compared to it's stated max of 5000 RPM. Considering I could actually see the belt turns then it certainly wasn't turning very fast ;0

Questions I have to clarify:

If your suggestion means that there is too much torque required to turn the prop because my gear ratio is too low, how would the controller know this? What is telling the controller that the effort is too much, the amp to RPM on the motor doesn't match up?

Is there any way to get live readings out of the controller to see what inputs it is receiving while running?

I'm certainly game to buy a bigger lower gear and new belt, but I have to be careful of the clearance to the Hull and might have to rejig the mounts.

I would love to know how you transfer the power from the motor to the shaft in your setup.

2. I will check on the heat but the wires are cool, and I can't feel any heat on the outside of the controller or motor. I will get a laser temp gauge and test this and post here.

3. according to battery monitor my volts never go below 46.5 on all my tests

Thanks for the advice!

Dan

[Danned]

The motor doesn't appear to be overloaded in any way and I presume the single beep is exactly the same as the confirmation beep when you first power up the controller.

I suspect that the controller is simply rebooting itself, but I can't see anything obvious that would cause this to happen.

What happens if you twist the throttle quickly from zero rpm to full throttle rather than increasing it slowly?

It might be worth checking the 4.3 volts across black and red throttle wires to see if the voltage on the red wire is somehow being pulled low when the throttle is twisted.
I'm wondering whether the controller's +5V supply is somehow being pulled too low by the throttle and causing the cutting out problem.
If the main processor shared the same +5V supply, it might explain why the controller momentarily dies and then reboots when the throttle is released.

Alan

 - Thanks Alan for the reply! Really appreciate the help here.
 - beep is the same as initial power up
 - when I run the throttle quickly I get faster load/RPM values but motor still cuts out
 - in my readings of the voltage, the voltage was pretty consistent at 4.3 volts I didn't see any fluctuations but I will double check today

[Bikemad]

Thinking out loud: I think that old gas engines like the Atomic 4 only run at about 25% efficiency so that 30HP is probably more like 8HP at the shaft at peak RPM on the atomic 4.

I can count the belt turns right now at 1Kw and it was about 180 RPM at the shaft, so my motor was only running at about 350 RPM. This is very slow compared to it's stated max of 5000 RPM.

If a gas engine is rated as 30HP, it should have an actual output of 30HP regardless of the inefficiencies and excessive heat losses involved in producing it.
If it were able to produce the same 30HP by burning the fuel more efficiently, it would still have the same power output, but the amount of fuel required to produce the same output power would be reduced.

The GM 48V 10kW motor is running at 80~81% efficiency when it is producing its rated 10kW power output at just over 3,500 rpm, but this does not mean that it is only producing 8~8.1kW as a result of the 19~20% losses due to inefficiency, it simply means that more battery power (~12.4kW) is required to produce the 10kW output.

So your 10kW (13.4HP) electric motor is only ~45% of the maximum power of the original gas motor's 22.5kW (30HP) not ~168%. 

Incidentally, I estimated the motor speed on the video to be at least 1,000rpm just before it cut out.

Is there any way to get live readings out of the controller to see what inputs it is receiving while running?

Apparently not:

For what it's worth, the online chat for Golden Motor is very helpful. I always assume that those are some sort of contractors or sales department, but they answered many of my questions so they have to be real employees.

I asked about the monitoring software and confirmed that *there is none*. There is a mistake on that VEC Controller Guide that needs to be corrected. It states that the "Operating status can be monitored in real-time", but that is not true. This only applies to the smaller controllers for bicycles.

I also noticed that your controller's heatsink is mounted directly to a piece of plywood, which is not exactly renowned for being a good thermal conductor, so you might want to use some longer screws and spacer tubes to enable cool air to circulate directly over the controller's heatsink.
If the controller is getting too hot under sustained heavy use, it will require some form of active cooling (electric fan and/or additional cooling fins, or even a water cooled heatsink).

However, if the cutting out was caused by the controller getting too hot and exceeding the "default value", I would expect it to produce 11 blinks of the indicator LED as detailed on page 5 of the VEC controller guide.

Alan
 

[Danned]

hello everyone

big shout out to Alan and GM for helping solve the issue. turns out it was the controller. Swapped out the controller and its behaving as expected.

thank you all for helping get me in the right direction.

dan

[Danned]

btw it seems that i’m at full velocity at 3.5 Kw according to my battery monitor so ill have to study the references for horsepower rating on the old Atomic 4. ill run some tests in heavier winds to get a feel for it but I’m glad the power is in the range of the old gas motor.

the final settings was to leave everything at default except I bumped the voltage throttle from 4 volts to 4.5 volts.

[Danned]

I also noticed that your controller's heatsink is mounted directly to a piece of plywood, which is not exactly renowned for being a good thermal conductor, so you might want to use some longer screws and spacer tubes to enable cool air to circulate directly over the controller's heatsink.
If the controller is getting too hot under sustained heavy use, it will require some form of active cooling (electric fan and/or additional cooling fins, or even a water cooled heatsink).


Alan

Thanks for the tips, I added in an aluminum standoff and when I get the water cooling in place for the motor I'll get a heatsink in place too. Thanks!

[Rusina]

Hi Damned,
Content pour toi, que tu aies résolu ton problème.
Donc, si j'ai bien compris, cela venait d'une anomalie propre à ton controleur et tu l'as changé?

[Danned]

Hi Damned,
Content pour toi, que tu aies résolu ton problème.
Donc, si j'ai bien compris, cela venait d'une anomalie propre à ton controleur et tu l'as changé?

Yes, I think that the controller was defective, as it didn't give any error codes, it was rebooting itself once some voltage load was put on it.