Customize alltrax controller for best speed

[JohnnieB]

I was out and about yesterday afternoon and this morning, but I've finally had a chance to look at the data logs and they show some interesting stuff.

Specifically, they show the need to upgrade all of the high current cables in a golf cart instead of just some of them. Sepex drive carts have 10 high current cables and Series drive carts have either 13 or 14 depending if the controller has an A2 terminal or not.

And they show the effect of underinflated tires, which translates to the low pressure type tires.

With a mix of old 6Ga and new 2Ga cable and the tires at 8PSI, the max amp draw was about 250A.

With all 2Ga cables and 8PSI, the amp draw increased to about 300A. That is about 20% more amps being drawn and torque is proportional to amp draw.

With all 2Ga cables and 15PSI in the tires, the amp draw maxed out at about 212A, indicating it didn't take as much torque to move the cart. Easier to move the cart means the motor will spin faster with the same amount of voltage applied, hence the cart goes faster.

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Of course this is only a single sample of two and there are too many other variables and unknowns to quantify the gains, but there does seen to be recognizable trends.

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I agree the average amp draw while cruising is higher than it probably ought to be, so there may be some extra drag coming from somewhere like gummed up roller bearings and dragging brakes shoes, now you got some baseline data to use as a yardstick for future comparisons.

[yurtle]

Crap. I should have asked for GPS speed for each run. Dunno if RPM is datalogged - which it ain't on my series.

One less data point. Amps at one speed against a load (hill slope), isn't the same as faster on the same slope, and it ain't linear.

Oh well.

[JohnnieB]

Originally Posted by yurtle

1. Crap. I should have asked for GPS speed for each run. Dunno if RPM is datalogged - which it ain't on my series.

2. One less data point. Amps at one speed against a load (hill slope), isn't the same as faster on the same slope, and it ain't linear.

Oh well.

1. The DCS drive doesn't have a speed sensor, so unlike the other sepex versions, the DCS version of the XCT doesn't have motor RPM in its data logs.

AS for GPS info, here is what was stated in Post#24:
"looks to me with my GPS, i increased speed with upgrading the other 3 wires by 1.5-2 MPH. and then another 1 MPH with adding 7 lbs of pressure to tires. I'm very happy with it how it is. about 21 mph on flat ground."

The cart ran at about 17MPH, gain about 1.5-2 when the remaining 6Ga cable were upgraded to 2Ga, then another 1MPH or so when tire pressure was increased and is now getting about 21MPH.


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2. It is far easier to see speed vs amps when RPM is recorded.

[Thrillercart]

Thanks for all the help. I’ll jack the cart up and see if the wheels drag or brakes drag at all.

Yes, the cart ran about 17 mph w just 7 new 2awg cables. Not it runs 20-21 w all 10 cables and 15 psi in tires

The batteries are 2018 model and the motor looks original. The motor says “electrical vehicle power systems, Syracuse, NY. Of course I can’t read any numbers on model, sn etc on the plates. But it’s a 1996 txt dcs.

I hope all that helps answer questions. I’ll check to make sure all wheels spin freely when jacked up off the ground.

2 questions: 1) when i let off the throttle, the card does pull down quite a bit (like the new carts do but not as abrupt. But does feel “Regen ish.” Is that right?

2) the rear differential next to motor looks to have a drain plug. Is their oils in this? Is there a way to check it? How should i check it/ service it If so?

[JohnnieB]

1. Feeling regen braking is normal when you lift your foot. You can adjust the how strong the regen braking is by connecting computer to the XCT.

2. The oil in the differential might be something holding the cart back. If it has never been changed, it is over 20 years old and probably has the viscosity of molasses in January.

To charge it, you have to drop the pan. EZGO puts 10oz on SAE30 motor oil in there, many people replace the motor oil with gear oil since gears are what is being lubricated, and other use a 80/20 mix of motor oil and STP.

I use gear oil (SAE85W gear oil and SAE30 motor oil have about the same viscosity) and reinstall the pan dry. Then pump in the gear oil with an inexpensive fluid transfer hand pump that fits on the bottle.