New Alltrax TXT48300 install question/issue

[bronsonj]

Thanks JohnnyB, the first thing I did on the Alltrax before I installed it was set the limit to 5,900. Close enough to 6k, but under. I've got 25" tires (I didn't measure, just hoping the sidewall is vaguely accurate).

So for whatever reason I'm not getting the full RPM limit on flat ground. I'll give it a longer run and see if it gets closer to 30.

I'll absolutely create some logs this week. Is it OK to set it on 1 second intervals or is 3 second OK or continuous?

[bronsonj]

Oh, regen braking.

I set the regen to be max of 75 amps. I am using a 45 Ah pack and they can handle 3C charge rates for short bursts so I presume 2C (90 amps) to be a safe real-world limit for a downhill regen run. I added a safety margin and set it to 75.

With the reduced weight, 75 amps of regen is really putting the breaks on! Almost don't need to use the breaks.

[bronsonj]

In case anybody is wondering about range. I ran it a little hard tonight... First night on the new equipment and all. I charged it up to 57.4v and ran it 3.9 miles and am at 54.0v now. So a little less than 1.0v per mile. That's doing speed runs with 500lbs of idiots on board, sometimes more. My safe range, never full charge or discharge, goes from 57.6v to 45.5v. If every mile cost 1v, (which it didn't) that'd be 12+ miles on my 58.8v (51.8 nominal) 45ah pack. At every point in the calculation I was conservative so I expect the real range to be substantially more.

[JohnnieB]

Originally Posted by bronsonj

Thanks JohnnyB, the first thing I did on the Alltrax before I installed it was set the limit to 5,900. Close enough to 6k, but under. I've got 25" tires (I didn't measure, just hoping the sidewall is vaguely accurate).

So for whatever reason I'm not getting the full RPM limit on flat ground. I'll give it a longer run and see if it gets closer to 30.

I'll absolutely create some logs this week. Is it OK to set it on 1 second intervals or is 3 second OK or continuous?

With 25" tall tires 27MPH = 4516RPM.

To get 30MPH, you'll have to spin the motor at 5018RPM, nowhere near the 5900RPM max you've set.

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The metric based tire sizing is more accurate then the inch based tire sizing, but both can be an inch or more off. A yardstick and a level is close enough, but if you want exact, measure how far the cart travels per tire revolution and due the math to get the height. I measure cart travel for four tire revolutions and averaged, so my tire height of 17.0395260947761" is fairly accurate. BTW: They are marked 18X8.5-8.

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Set the sample rate to continuous for the most accurate data. You get from three to five samples per second, so the files can get pretty big, but small compared to picture files. IIRC, I've recorded trips that lasted over an hour and the file size was only about 2 MB.

[bronsonj]

Hey Johnnie B,

I created two logs. one with sample at once per second the other with continuous. Both short jaunts to/from DQ.

I changed them to .txt because the forum won't let you upload a csv format, but they were still too big. That's why they are .txt inside the zip file... Sorry for the confusion.

Lemme know what you find.

[bronsonj]

Just noticed, it says "Field Map: IQ-V4". Is that right for my TXT48? Isn't the IQ a Club Car?

[JohnnieB]

Originally Posted by bronsonj

Just noticed, it says "Field Map: IQ-V4". Is that right for my TXT48? Isn't the IQ a Club Car?

Contact Alltrax to get correct field map for your motor (Stock TXT-48 )

[JohnnieB]

Originally Posted by bronsonj

Hey Johnnie B,

I created two logs. one with sample at once per second the other with continuous. Both short jaunts to/from DQ.

I changed them to .txt because the forum won't let you upload a csv format, but they were still too big. That's why they are .txt inside the zip file... Sorry for the confusion.

Lemme know what you find.

The first one was faster than the second one.

DQ run-1:

Duration = 149 seconds
Number of samples = 149 (1/Sec - not very good resolution of events vs time)
Average speed = 17.3MPH
Average battery pack voltage = 54.0V

Max RPM = 5053RPM (30.2MPH on 25" tires with 12.44:1 gears)
Max Battery current = 228.6A
Minimum Battery voltage = 51.2V

Max Regen current Battery = 54.2A
Max Regen current Armature = 82.6A
Max Battery voltage = 55.3V

Minimum Field Amps = 2.5A at 4995RPM and 5033RPM
Max Field Amps = 25.2A at 768RPM
Max Armature Amps = 254.4A

Average battery amps at top speed = About 66A


DQ run-2:

Duration = 162 seconds
Number of samples = 742 (4.58/Sec - reasonably good resolution of events vs time - I'd prefer 10 samples per second or higher, but that is all you can get from an Alltrax XCT. )
Average speed = 13.7MPH
Average battery pack voltage = 53.7V

Max RPM = 4890RPM (29.2MPH on 25" tires with 12.44:1 gears)
Max Battery current = 304.1.6A
Minimum Battery voltage = 50.6V

Max Regen current Battery = 50.4A
Max Regen current Armature = 79.7A
Max Battery voltage = 54.9V

Minimum Field Amps = 2.4A at 4797RPM
Max Field Amps = 27.0A at 1478RPM
Max Armature Amps = 296.6A

Average battery amps at top speed = About 68A

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BTW: I got the speed by dividing RPM by 167.26..... (which is miles in inches divided by circumference of tire multiplied by differential gear ratio to get motor revolutions per mile and then divided by 60 to get RPM)

The more accurate the tire height, the more accurate the speed based on recorded motor RPM.

[scottyb]

Attached is the latest TXT48 stock motor map. Don't open it as that may corrupt it. You can't read Chinese anyway . Simply save it to your desktop and select it when the software prompts you to do so.

[bronsonj]

Thanks JohnnieB and Scotty! Looks like new logs tonight or tomorrow... :)