Troubleshooting after Controller upgrade on TXT 48v

[mgray70]

Originally Posted by Hill climber

Great catch - I did find the stray black wire that was never reattached. Charger working a-okay now [emoji106]



So if the motor is sick then it's sick. But I find it strange that I never had any issues until upgrading the controller/solenoid/2ga cables. Is it possible the new controller did this? Or just a coincidence that it would have given out whether or not I replace controller? Something else that isn't yet diagnosed? Just want make sure i don't fork over money for a new motor only to find that the issue isn't fixed...

It was probably a problem that was about to show up before you upgraded. A kinda good feature about the Alltrax is that it will sense an issue such as a short, or open circuit and shut down before it creates more problems. I would suspect either worn/ stuck brushes, or just a broke brush wire inside the motor case.

Sent from my SM-G970U using Tapatalk

[JohnnieB]

Originally Posted by Hill climber

Great catch - I did find the stray black wire that was never reattached. Charger working a-okay now

So if the motor is sick then it's sick. But I find it strange that I never had any issues until upgrading the controller/solenoid/2ga cables. Is it possible the new controller did this? Or just a coincidence that it would have given out whether or not I replace controller? Something else that isn't yet diagnosed? Just want make sure i don't fork over money for a new motor only to find that the issue isn't fixed...

Good to hear the charger is now working.

Since the cart was built in 2016, the motor is only about 4 years old and the stock TXT48 motor is a sturdy one, but tall tires, heavy loads and hills will kill it. At worst, the upgrades controller, solenoid and cables only quickened the inevitable. In fact, I suspect it was on its last legs before the upgrades were made, or at least there was a statement in your original post indicates that fact.

"I took it out for a test drive in my hilly neighborhood (more torque for hills was the reason for the upgrade), and while everything seemed to be working fine, I didn't notice any power or speed difference at all on a quick down the street and back ride."

In the Freedom mode (Performance mode list attached), the stock TXT48 controller (Curtis 1206HB) limits the motor to 4400RPM, which is 18.9MPH on 18" tall tires and about 24.2MPH on 23" tires. When the 4400RPM limit is removed, the stock TXT48 motor will spin at about 5600RPM when powered by a fully charged 48V battery pack, which is roughly 24.1MPH on 18" tires and 30.8MPH on 23" tires. Since no increase in speed was noted, there is a high probability the motor was already severely damaged and the upgrades just performed a coup de grace.

The stock TXT48 controller has a 250A throughput and A XCT48500-TXT48 turned down to 400A should produce a 60% increase in low end torque. Of course that torque increase is only available below the RPM at which the motor is capable of drawing over 250A, but it should have registered on the seat of the pants dyno when acceleration from a standstill.


----------

Your stock motor might be repairable. If it is it might last another few years, but tall tires, heavy loads and hills will take it out again.

[LSUgoTIGER]

Originally Posted by JohnnieB

...the stock TXT48 motor is a sturdy one, but tall tires, heavy loads and hills will kill it.

JohnnieB, if all of these conditions combined will kill the stock motor, what about just taller tires (22" or 23") if terrain was completely flat and you have minimal loads. They say 2 out of 3 ain't bad, so 1 out of 3 must be better right?

[JohnnieB]

Originally Posted by LSUgoTIGER

JohnnieB, if all of these conditions combined will kill the stock motor, what about just taller tires (22" or 23") if terrain was completely flat and you have minimal loads. They say 2 out of 3 ain't bad, so 1 out of 3 must be better right?

Heat kills motors and the slower a motor spins, the more amps it can draw. Depending on the motor's efficiency (50% to about 85% depending on RPM and some other factors) some of those amps are converted to torque and the rest into motor heat. The amount of heat produced increases exponentially as the amps increase (W = I² * R).

Tall tires cause the motor to spin slower at any given speed, so more amps can be drawn and more heat produced. If the cart is only driven on hard level surfaces and not driven at walking speed or less from long distances, the motor might last almost as long as it would have on stock height. A 10°F increase in the motor's average operating temperature halves its estimated lifespan, but with proper maintenance (brushes, bearings and cleaning), a typical cart motor's operating lifespan is 20 to 30 years or more.

Other than when accelerating from a standstill and when climbing hills, weight isn't all that much of an issue since on a hard level surface the rolling resistance doesn't increase all that much as more weight is added. However, going uphill the motor has to lift the cart and cargo against gravity and the more the total weight the more amps the motor has to draw to lift the load.

Bottom line is most stock motors can handle standard inflation pressure tires up to about 22" tall driven on a hard level surface without drastically shortening its lifespan.

Add tires taller than 22", low pressure (max inflation pressure of 10PSI or less), soft surfaces (off-road, mud, sand), hills or any combination thereof, to the equation and a motor better suited to the application is likely to be needed.

[Hill climber]

Update: I finally was able to borrow a friend's PC so we could check out what the Toolkit software was telling us. I've attached two screenshots with the cart at a standstill (on the second one I drew in the two error flags that kept coming up while driving - overcurrent and shutdown). I later figured out how to record a drive on the monitor tab, but the forum won't accept a .csv file. Is there another way to provide this info? A couple things I noticed:

1. The battery voltage reading is lower than what I had been getting when I test with a multimeter. Did not test before the run but they are usually over 51v with a full charge. Tested after the run and they were at 50.8. Highest reading during the runs was right at 50. I did have the lights on because this was at night - could that have changed it?

2. I noticed on the lefthand side it says the controller rating is 500a. The dealer I purchased from said he would preprogram with correct field map and turn it down to 400a since I have the stock motor. I don't know how to verify this was done correctly but maybe someone else can. Could this be the reason for all the trouble?

3. Looking at the .csv file, when I start giving it 100% throttle, it shuts itself off - frequently flashed the shutdown and overcurrent flags, and once or twice the reverse horn would beep, even though I was still in "forward." After letting it rest for a few seconds, I was able to get it going again but kept hitting the same problem.

4. Speed limit is set to 2500 RPM - that seems way too low?

What do you think - is there anything here that can help diagnose the issue?

[JohnnieB]

Zip the .csv file and post the .zip file.

Your controller's max motoring amps is turned down to 290A and a stock TXT-48 controller has 250A, so your more or less running at stock controller with oversized tires. The speed limit RPM is set to 2500RPM, which is 13.8MPH on 23" tires. Turf mode is selected, so it has a very slow takeoff from a standstill.

No wonder you didn't notice any change in speed or torque.

IIRC, the stock TXT-48 motor can handle 500A, so move the Max Motoring slider all the way to the right.

Move the speed limit slider to 6000RPM, which is 33MPH on 23" tall tire (theoretically), but probably won't reach that fast due to more torque being needed to turn oversized tires. You can tweak the RPM value to give you a safer max speed.

The Street mode is far more responsive than the Turf mode, so if you select it you'll probable need to turn down the Throttle Rate from 35% to about 15% and tweak from there to find what is comfortable for you.

You might also want to turn the turbo mode on.

Record a data log with the new settings and post it also.

[Hill climber]

Update: Made the suggested changes and could definitely tell a difference, but still getting a strange shutdown that I can't figure out.

I first tried to re-record a run with original settings, and almost was not able to replicate the shutdown. It finally cut out at row 231 on the 6.24.20 file.

I changed the settings to 400 motoring amps, 400 battery amps, and speed limit to 6000 RPM. Also checked the "street" box. Speed and torque were noticeably different, as expected. The recorded run is in the 6.24.20 v2 file. It would do the same thing where it would cut out and flash both the "shutdown" and "overcurrent" error flags, but a couple new changes - now the "low battery" and "precharge fail" flags were coming on as well. If I waited 2-3 seconds it would sort of reset itself and allow me to drive again. Then at the tend of the run, it shut down, but also kicked on the brakes with some force. From there on it wouldn't even reset itself. If I press accelerator, the solenoid clicks, but there's no movement. I see that the motor voltage shows 0 while the throttle % moves with how I press the pedal.

Any ideas for what's going on or next steps to try?

Related - I mentioned the battery readings from a standstill on the controller differ from what I test with the multimeter. I forgot to check on that tonight, but have no reason to believe it would be any different from last time. Is this an issue of any significance?

[JohnnieB]

You battery voltage (as measured by the controller between the controller's B- and B+ terminals) is dropping excessively under load.

In the 6.24.20 file, it dropped to 36.4V with 128.6A being drawn. The under voltage slider was set for 38.5V so LOBAT was triggered, followed by the global shutdown and other errors. The battery voltage almost instantly climbed to 50.2V when the amp draw from the battery drop to <1A, so I suspect there is a cable, connection or contact with excessive resistance rather than bad batteries.

A similar observation made in 6.24.20v2, dropping to 38.2V with 111.4A drawn, but LOBAT had already been triggered be a slightly earlier low voltage.

------------
The thing to remember, it isn't what the battery pack voltage is as measured between the main plus and minus terminals, it is what the controller see between its B- and B+ terminals.

--------------
I also noticed the battery voltage in the log went done to 0V at times. Were you flipping the run/tow switch to tow occasionally????????

Otherwise, something is amiss with the controller.