Alltrax XCT48400PDS + Admiral B2 settings questions

JigginJim77

Hi all! My cart is finally up and running after much troubleshooting and parts. I have a 2006 EZGO TXT PDS 36v with 6" spindle lift, 12" wheels/23" tires, 2+2 seating. I've just finished repairing/upgrading with an Alltrax XCT 48400, SW180, 2 ga cable set and Admiral MOT-B2. I have the most recent field map installed(version 4). I don't get top speed because I know my battery pack isn't great. Only charges to 37.9v.The buggy runs good, but I have a few questions.

1) Speed ssensor setting in the toolkit set to 4 pole?
2) I get a max rpm of about 3800 with the 4 pole ssensor setting. A function of the battery pack being weak? The cart is hitting about 21, verified via GPS.
3) No errors flagged in the monitor page, but battery pack voltage drops to 29.8v on full throttle starts. It recovers fairly quick, but doesn't get back to pack voltage fully.
4) Using the default speed curve, the throttle is a bit snappy from stop unless you are gentle with the pedal. Suggestions to tame that? I have the throttle rate set at 40% now.

To be honest, I'm getting 21-22 mph now. Pretty sure I don't need the full speed of close to 30. Our community speed limit is 10 mph, but I know which residents are the official speed traps...

BGW

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scottyb

Replace those batteries ASAP and the performance will improve.
running on low voltage causes excessive amperage draw which voids your motor warranty as does running on any map not specifically for the B2 motor.

JigginJim77

I was afraid you were going to say that. Batteries are not in the equation this close to Christmas, unless the wife is planning on really excellent gifts Actually we bought the cart from her "friend" so I could play that card, but I like being married to her !!!

JohnnieB

Apparently the 4-pole setting is correct. With 23" tall tires and stock (12.44:1) gears in the differential, 3800RPM is 20.9MPH, so the RPM vs MPH number match.

As for the takeoff being too snappy, backing off on the throttle rate will help some. Try about 20% and tweak from there.

However, throttle rate is how fast the controller's output responds to pedal position and the pedal may still be too sensitive on the first portion of its travel. I altered the throttle linearization so the first half of pedal travel only tells the controller to output 30% and the second half goes from 30% to 100%. That gives me more finite control when maneuvering in tight places as well as the ability to takeoff from a standstill on wet grass and not spin the tires. (See attached)

As Scotty mentioned, make sure the filed map is for a MOT-B2.

As for the batteries only charging to 37.9V (90% SoC), try some back-to-back charges.
Basically, initiate charge cycles after the charger shuts off and before cart is used again.

When I got my cart, the T-105 batteries would only charge to 85% SoC and after two months of back-to-back charges, they would charge to 95% SoC. When I went to 42V a year or so later, they were going to 100% SoC.

Attached Images

Throttle Linearization - JBB.jpg (164.2 KB, 0 views)

JigginJim77

Thanks JohnnieB. I do have the correct map for the MOT-B2. I will try the suggestion on the battery charge. If that doesn't work, I'll just have to baby the cart till a new pack is in the cards. I keep the charger plugged in for the time being.. I'll adjust the throttle curve a bit more to settle it down.

Thanks for the file. It will help me fine tune.

Jim

JohnnieB

It depends on which charger you are using. Most just shut off when the pack voltage reaches an on-charge voltage of about 45V and have to be unplugged from cart to start a new charge cycle.

JigginJim77

I'm using a Power wise QE and it does exactly that. I have to unplug and wait about 30 min for the pack to stabilize, the plug in again. I've been through several cycles now and the pack voltage was 38.0 with my DVM. Alltrax toolkit reported 37.9.

I used your strings with a 35% throttle rate and the response is much more tame. Wonder why I don't get a separate tab in the software for Throttle Linearization like in yours.?!?

JohnnieB

Got to Tools > Options to access advanced features. The cut and paste from the manual shows how to turn on Throttle Type editing, but Throttle Linearization is on the same list. (One of the first things I did was check out all the drop down menus on the toolbar. )

The battery voltage shown on the monitor screen is between the B- and B+ terminals on the XCT, so it can be a bit different than what is measured between the main + and - terminal on the battery pack.

Also, the voltage between the XCT's B- and B+ terminals will be a bit lower than the pack voltage until the solenoid contacts close.

Attached Images

Advanced options - Throttle Linearization.jpg (64.3 KB, 0 views)

JigginJim77

Happy to report after several equalization charges my pack voltage is stable at 38.13 volts! Buggy runs pretty darn good now. Pretty sure this won't be the last thread though...

Gibb

Glad to hear your getting the batteries close to 100% I did the same thing a few years ago and got about an extra year out of the pack. Just curious what your top speed is now? I have about your same setup and Im getting about 21 22mph.