stock motor question

[shrpshtr]

as best i can tell, i have a Fleet Speed motor in my 2005 TXT Series cart. a02-4012. (stock motor that came with the cart) i can't find a spec sheet on it but best i can tell it is a 275 amp motor. can anyone confirm this for me? i am getting 14-15 mph (which is good for that motor based on what i am reading) with 22x11-08 all-terrain tires. i am definitely going to need more torque though. thanks in advance.

shrp

[Phil_R]

I have a 2005 TXT series (fleet) cart with original stock motor. Can't confirm the motor is 275 amps, but the stock Curtis controller is 275 amp. 22"x11"x10" AT tires on 10"x7" (3+4) wheels... same speeds you are getting.

Upgraded to Alltrax SPM-48500, Super Duty Solenoid, Heavy Duty F&R Switch Cam, and 2 gauge Premium Cable Set. (ScottyB @ Carts Unlimited, site sponsor) This upgrade returned all torque lost with 22" tires, and then some. Top speed is the same as your cart, but the torque at take-off will put a smile on your face.

[JohnnieB]

You can download the Owner, Service and Parts manuals for your cart here: http://www.buggiesgonewild.com/elect...g-manuals.html
They are the three .pdf files near the top.

The stock motor in a '05 TXT Series is rated 2.5HP @ 2700RPM. No Amps are specified and at a higher voltage, it spins faster.
Lots of people run stock series motors at 48V and some go 72V and beyond.

The stock controller is 275A.

With 22" tall tires, you've lost about 31% of the stock torque.
Upgrading to a 400A aftermarket controller will up the torque by about 33% and get you back to stock torque levels, plus a little.

Mathematically, you should be getting in the 17 to 18 MPH range, so the batteries are weak and/or the high current loop has excessive resistance in it.

[shrpshtr]

Originally Posted by JohnnieB

...
Mathematically, you should be getting in the 17 to 18 MPH range, so the batteries are weak and/or the high current loop has excessive resistance in it.

Thanks for the both of the prompt responses. JohnnieB, should the 17 - 18 mph range be with the upgraded 400 amp controller or with the stock 275 controller. i wasn't sure if this part of the response was geared towards me or phil_r.

phil_r, would that return to normal torque help with climbing steep embankments and gradually sloping hills?

shrp

[Phil_R]

Originally Posted by shrpshtr

phil_r, would that return to normal torque help with climbing steep embankments and gradually sloping hills?

shrp

Short answer, yes... on embankments and inclines where the cart used to slow down, it will now accelerate. My top speed test was on a damp lime-rock grade. With tires at maximum recommended pressure and on level pavement, top speed would likely match JohnnieB suggested speed.

[JohnnieB]

Originally Posted by shrpshtr

JohnnieB, should the 17 - 18 mph range be with the upgraded 400 amp controller or with the stock 275 controller.

Either one. The 17-18 MPH is based solely on the circumference of 22" tires vs the circumference of stock (18") tires, both with a stock (12.44:1) differential ratio.

On the other hand, the fact you are not reaching that speed range is electrical.

In a series wound motor, Amps equate to Torque and Volts equate to Speed.
Losing speed going up hills and having poor acceleration are Torque issues. Basically, you need more than 275A to get those tall, fat tires turning and then keep them turning at the same speed on a hill.

However, it doesn't take nearly as many Amps to cruise at top speed on a hard level surface, so you should be getting close to 17MPH or so, with a stock 275A controller. You just won't get there quickly and if there is much of an incline, the cart will slow down.

Since you are not reaching the higher speed range with 22" tires and a stock controller, either the battery pack voltage is dropping more than normal under load and needs to be replaced, and/or the high current cables, solenoid and/or F/R switch need to be replaced.

[shrpshtr]

great stuff JohnnieB. in all the reading i've found thus far (3-4 articles basically) they say the TXT series cart should only expect between 12-14 mph with stock setup. i was actually surprised i was still getting the speed i am with the larger tires and rims. is there a way to check things to see if i am getting the proper voltage? thanks again for everyone's comments.

shrp

[JohnnieB]

Owner manual says 12-14, Service manual says 13-14. Take your pick.

I screwed up on the tires sizes and speeds. I was comparing 22" vs 26" tires a bit earlier and I changed the the 22 to 18 in my spreadsheet without changing the 26 to 22.

The correct info is that you're loosing about 18% of the stock torque and the speed range should have increased from 12-14 to 14-16, so about 15MPH is in the ballpark.


You might be loosing a little voltage, but not all that much.

It almost takes two voltmeters to check for lost voltage.
One across the main positive and negative terminals on the battery pack and one between the M- and B+ terminals on the controller.
The difference in those two voltages is the voltage loss in your setup.

You can measure one voltage than measure to other voltage, but you have to do them back to back over the same stretch of ground to get meaningful comparisons.

[shrpshtr]

great info. thanks JohnnieB!

[yurtle]

Originally Posted by JohnnieB

I screwed up on the tires sizes and speeds. I was comparing 22" vs 26" tires a bit earlier and I changed the the 22 to 18 in my spreadsheet without changing the 26 to 22.

Could you please post your spreadsheet?