Confused/Disappointed with New Altrax XCT48500PDS with ML3

bubba4dad

Ok, I upgraded my 36 volt PDS to 48 volts. New everything. Controller, solenoid, motor, wires, batteries, etc.

1.) XCT500PDS Controller
2.) 400a solenoid
3.) 2 gauge cable set
4.) ML3 speed control
5.) Digital Dash Meter
6.) Admiral B2 motor
7.) 48v x 12v Reducer
8.) Yewy 1200z onboard charger
9.) 6 new 8 volt Trojan Batteries

The cart has 23" tires.

I have not had any luck with the ML3 and the three settings in the controller.

The controller came with the RHMOT-B2-V4 field mapping but it was set to an 8 pole speed sensor. With this, the cart would run 28.4 mph on all three ML3 switch settings.

After a little research and advice. I changed the speed sensor input to 4 pole.
Now it runs right at 3000 rpm's and a speed of 15 mph on the "normal" mode.
Mode 2 increases to about 3500 rpm's and a speed of 19 mph.
Mode 3 increases to about 4200 rpm's and a speed of 24 mph.

Normal is set for 3000 rpm, Mode 2 is 4000 rpm, Mode 3 is 5997 rpm. These were the setting that the controller come with. I have not reset nor changed anything other than the speed sensor # of poles.

If I turn the speed sensor off in the controller I can get 26 mph. If I change it back to 8 pole it will top out at 28 mph.

I need help. I do not know what I need to do next.

Why cant I get the 4000 rpm's in mode 2?
Why cant I get the 5997 rpm's in mode 3?

Also when accelerating, The throttle position will go to 100% for a few seconds and then it drops back to 90% and the cart slows a bit. Is that the regen doing that?

I know I have a lot of questions but this is starting to look like a $ 2700 upgrade mistake.

BGW

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BBBHC

So I am certainly not a well informed golf car enthusiast. I googled the admiral B2 motor and it seems to be a high torque motor. If you were looking for more speed, which is what I am assuming from your post/questions, I believe you should have gotten a high speed motor.

As it is, from what I saw, you are exceeding it's high speed rating of 18mph @48v.

Maybe scottyb or tahoedawg would be able to give you good information, They know their stuff!

CrazyDad

I have a dcs cart with the same setup as you minus the ml3 and I get 28 mph top speed with 22” tires so that looks right. Have you called alltrax? They could answer these questions today. I can see the need to limit speed as 28 is fast in these carts.

bubba4dad

I am not looking for more speed. I am questioning the functionality of the controller.

bubba4dad

I would be fine with the 28 mph but the only way I can get it is to lie to the controller and say its an 8 pole speed sensor.

bronsonj

I know that the faster the motor spins the fewer amps it can draw. There's some fancy reason behind this, but that's not something I can explain... 28mph may just be the electro-mechanical limit of your motor.

As for not getting 4000 rpm in mode 2, how do you know you are not? 4k rpm should net you a theoretical maximum of 22 to 23 mph roughly. Assuming you have correct high pressure tires inflated all the way, your brakes aren't dragging, you don't have alignment issues, etc.

Mode 3 may net you a theoretical maximum of 34mph, but every bit of drag will be more impactful to your speed the faster you go. Wind resistance increases, your motors ability to draw amps decreases so tires at 8psi or a full windsheild or a bad alignment all have a significant impact at the far end of what your cart can do on paper.

http://www.buggiesgonewild.com/speed-calculator.php

Easiest thing to check is tire pressure. See what your max is stamped on the side of the tire and put your pressure close to that and rerun. If you have low pressure tires (under 12psi) then it will be a lot of resistance regardless.

Good luck and let us know what you find.

JohnnieB

What is the max inflation pressure embossed on the sidewalls of you 23" tires?

What are you using the determine cart speed? (Inconsistencies - IE: 3000RPM = 16.5 MPH for your cart and you say it is going 15MPH - RPM vs MPH listed for modes 2 and 3 are much closer.)

Please record a datalog showing all three modes at max speed on level pavement, preferably the same stretch of level pavement.

Zip the resulting .csv files and post the .zip file here.

scottyb

Also - try setting the regen to zero on mode 3 and like Johnie suggests, collect and share a monitor file while driving.

WalterM6

The problem I see is that you don't know exactly what kind of magnet you got in your motor. Two solutions. Remove the magnet. Make a mark on it. Get a compass. Slowly rotate the magnet and count how many time the compass needle changes directions per revolution. A four pole will change from N to S to N to S each 1/4 turn. Second replace the magnet with one that you know is either 4 or 8 poles. Either will work as long as you have it correct in the software.

JohnnieB

No need to break out the compass, an Admiral B2 motor has a 4-pole magnet disk.

When the XCT is set to 8-pole, the controller believes the motor is spinning at half the RPM it actually is, which is why all three modes had the same top speed.

The settings of 3000RPM, 4000RPM and 6000RPM are effectively doubled when a 4-pole motor is connected to a controller set for 8-poles, so the RPM settings for the three modes became 6000RPM, 8000RPM and 12000RPM. His Admiral B2 motor connected to his 48V battery pack with the drag imposed by his cart will spin at a max of 5193RPM (28.4MPH), which is lower than any of the artificially high RPM settings resulting from the controller being set to 8-poles.



BTW: An 8-pole magnet disk has four N poles and four S poles and a 8-pole speed sensor puts out 4 pules per motor revolution. (Same pulses per revolution as a V8 car engine, so a automotive V8 tachometer will work for an 8-pole motor and a tach for a four cylinder will work with a 4-pole motor.)