GoldenMotor.com Forum

Update: so far, I've been able to confirm that the reverse button does indeed swap direction of motion even with a hyperbolic throttle, provided I go to neutral first (makes sense).

When I short the regen brake button, regardless of spin direction, the motor stops quickly and I get the 17 beep alarm that I'd expect when regen is on (as seen on other posts). Whether this actually recharges the batteries or not remains to be seen, as the motor isn't yet connected to the propeller, nor indeed is the boat in the water yet.

Hi everyone, I'm hoping you can help me with some questions regarding reverse and regen:

I have a GM BLDC 5kW motor and a VEC300 controller on my sailboat. Due to the way the motor sits, the boat goes forward when the motor turns anti-clockwise. Last year, I had a DIY potentiometer throttle that didn't last long, so I've bought a hall-type throttle from Miromax. It seems alright but it can only be installed in such a way that pushing the lever forward delivers a lower signal, ie it sends a reverse signal to the motor.

Now, since this direction of motor rotation is what makes my boat go forward, it seems perfect. But, I won't get any regen as the motor will always be "reversing". I know I can swap the blue and green cables, plus the hall cables, to reverse the default forward direction of the motor, but that would mean that pushing my throttle forward would make the boat go backwards.

My questions:

- How can I keep the throttle in its current position, while still being able to get regen?

- Does shorting the reverse button just swap the direction of movement? If I short the reverse switch, will it just swap which way my boat goes relative to the throttle signal?

- Does the reverse switch even work with a hyperbolic throttle type, where you already reverse by moving the throttle backwards from the midpoint?

- If this is the case, can I short both regen and reverse buttons to "swap" the direction that the controller considers to be forward, allowing regen to take place?

I have no experience with the EZ Bluetooth App so I don't know what temperatures it actually monitors and displays. Are you sure that it's the motor that's overheating or could it be the controller?
 

I am positive it is the motor overheating. Through the GM monitoring app on WeChat, I can see them temp limit is 150degC for an alarm and 155degC for it to depower. 160 degC is Shutoff. I watch the live motor temp reading say 155degC. The controller also has temp limits to it, but I am reaching the motor temp limits before the controller.

Does your coolant flow in series through the motor first and then through the controller?

Coolant flows from controller to motor but with a small temperature differential between the inlet and outlet temp of the coolant, I don't believe switching the order of this will help very much. Especially because the motor temp is far hotter than the coolant. a 3 deg temp differential will not cause a huge difference in heat transfer between motor and coolant.

What rpm is the motor running at when it's drawing the 140 Amps?
If the motor speed is considerably lower than its rated 3,500 rpm it might be running too hot because the motor is being overloaded, in which case a smaller pitch/diameter prop (or possibly a gear reduction on the propshaft) may be required to reduce the load on the motor to allow it to operate at a more efficient rpm, which should then generate less heat in the stator windings.

Motor is running at roughly 3600 underload.

I would like to note that the cooling loop on top of the motor (where ALL the cooling is located) does stay cool. Cool enough I can touch it. But  moving down to the middle of the motor, it gets so hot on the outside casing that it could burn skin. I am wondering if GM just has an inadequate cooling system for their motor to run at full power for any extended period of time.

Check the outlet temperature of the water cooling. If the delta T is large, then you would benefit from moving more water. If the delta T is small, then you wouldn't, and the limitation is somewhere else.

The temperature difference between inlet and outlet is roughly 3 degrees F. It is not a large difference but with cooling, the more mass that flows through, the more heat will be exchanged. My issue though is that when I run the 5kW motor at 140 amps for an hour on a 52V setup, it still overheats. I would agree there is enough water cooling it but I should be able to run this hard for an hour. This is the only thing I can think of that would be fixable.

Hi Gilles,

Thanks for the update, it's good to know that you've managed to locate and rectify the problem.

I'm pleased for you that you now have it working correctly.

Alan