Driving slow

[WejaZ28]

I read here that our motors do not like to be run at slow speeds? The majority of my driving is done cruising around the golf course and neighborhood at less than 5mph, with a few big hills mixed in.

Is there any way to program the Alltrax controller to draw less Amps/Voltage at slow speeds(ie...program torque out of the lower end of curve).

[WejaZ28]

Johnnie B, no thoughts?

[JohnnieB]

You could reduce the max battery and motor amps down to about 300A or so instead of 400A like it should be for a stock PDS motor and toning down the throttle torque curve might help too. Alltrax might have some better suggestions.

There might even be a better field map for low speed driving, but I've never heard of it.

You've got stock height tires according to your signature block and that's a plus. Taller tires make the motor turn slower for any given speed and the slower the motor turns, the higher amps it can draw. That's why driving a cart with tall tires slowly is so deadly for motors.

Of course, we don't know if your motor is running hot or not.

Zap it with an IR thermometer after a long slow cruise. If it stays below 170°F, your not having an overheating problem.

Also, record some data logs and see how many amps are being drawn.

[WejaZ28]

Thanks for the thoughts. I'll run a few logs. Lost my IR thermometer, getting another.
Motor was really hot to the touch after taking a break at top of a hill on last cruise.

[JohnnieB]

The windings are Class-H, so the max winding temperature is 180°C (356°F), but we are measuring at the case, so it is prorated down to 115°C (239°F) max at the case surface. Also, a motor has a large thermal mass, so the case temperature continues to rise after the motor stops.

If the motor is cool enough to touch, it isn't overheated.

A 50°C rise is fairly typical for continuous operation and at an ambient air temperature of 77°F (25°C) that adds up to 75°C or 167°F, which is too hot to touch for most people. Like I said earlier, if it is below 170°F, there is nothing to worry about.

When I was running an Alltrax DCX controller (forerunner to the XCT), I monitored my motor temperature with a thremocouple attached to a DMM with a Min/Max function. Got it above 200°F a few times because the field mapping would take the field current below 1A to up the top speed.

[WejaZ28]

Good to know. I'll follow up when able.

[WejaZ28]

Kind of off topic, but why does the Alltrax program not allow file manipulation unless your hooked up to the controller.
I used to do tuning for my cars via HP tuners, LT1 & LS1 edit etc...I was always able to alter files within the program on the laptop, save them to file, then upload the file to the vehicle at a later time. Would be allot nicer editing in the house A/C on the couch, instead of a sitting on a cart in a 110 degree garage.

[JohnnieB]

Don't know how far your couch is from your garage, but Alltrax does have a Bluetooth module for programming it.

[WejaZ28]

Expensive connection.............

[JohnnieB]

Originally Posted by WejaZ28

Expensive connection.............

'tis a bit more $ than a USB printer cable, but like more speed or more torque, more convenience costs money.