Torqu increase questions

tyhuck

Been building a 96 TXT complete with 500 amp controller, 48v upgrade, and 15:1 torque gears. I found the appropriate information to calculate my speed to determine that I will be running somewhere close to stock 36v speed, but I am just curious as to the percentage of torque increase I have achieved from my upgrades over a stock 36v cart. I know the gear gives me roughly a 20% increase, but what percentage of an increase did I get from the power upgrades?

Also, is there a way to adjust my throttle inputs so that it doesnt snap your head back when you touch the accelerator? Basically I hit the throttle, hear the click of the solenoid and slowly apply pedal until it moves, but it goes from no power to about half power instantly and I was wanting to throttle it back so that it eases in a little softer under light pedal. Its an altrax 48500, and I know its programmable but I need to know how to program it.

BGW

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tyhuck

OK, I actually came across the info while continuing my online research. Funny how that happens. I searched a good while not being able to find anything to answer my questions, then a short time after posting my question, I find an answer.

FWIW, I determined that I would be increasing my torque a good 55-60% over a stock controller and gears, vs. with my current setup. Does that sound right?

I also found the software I was looking for to adjust my programming, and detailed instructions. Was having trouble with dead links, but I guess it was my internet connection at work filtering stuff out.

JohnnieB

You need to include tire height into the torque gain equation.
For example, a stock height tire has an effective gear ratio of 1.33:1, so the final drive ratio of a cart with stock tires (18") and stock gears (12.44:1) is 16.59:1. Swap out the stock gears for 15.00:1 gears and the final drive ratio is 20.00:1, or a 27.4% torque gain.

Going from 36V to 48V is a 33.3% increase in both speed and torque, so total torque gain throughout the RPM spectrum appears to be 60.7%.

The torque gain from swapping the stock controller to one with a 500+ amp throughput is only realized at RPMs lower than the minimum RPM your motor is capable of drawing more amps than the max amps the stock controller can pass, so it is more or less negligible when the cart is traveling faster than walking speed.

To tame the take-off, dial the throttle rate back to about 15 and tweak as needed from there.

Also, you may need to modify the throttle's Linearity, Torque and Speed curves

tyhuck

Thanks.

I'm running 22" tires, but was also running the same size on my last cart that was all stock, so I thought the comparison wouldn't be dependent upon tire size since both cars ran the same size tire.

JohnnieB

Unless you physically measure the tire heights, they might not actually be the same height, but the only way we have to measure torque is by the seat of the pants unless you has access to a dynometer.

tyhuck

Exactly. There is a considerable increase in torque over my last cart. I was just trying to figure out a ballpark figure for how much I increased it. I haven't seen any figures on what the factory setup puts down in Ft/lbs, so it was all just conjecture and assumption anyway. My mind kinda works that way, and if I get an idea or a question in my brain, I gotta get it out somehow or it will drive me insane. This satisfies my eccentricity and gives me an "answer" to the original question.

Gotta wait for my new charger to get here before I do anything to the programming. Not that I need a full charge for the programming, but for the testing. I want to make sure that the batteries are all topped off and ready to go before I take it out to try my adjusted program settings.

JohnnieB

What drive system do you have Series or SepEx (DCS)?

Sounds like we share eccentricities.

tyhuck

Series. I stick with series setups because they are the harder working of the two, and since my cart use consists of getting in and out of the deer lease, hauling stuff around, and taking on yard work tasks I'm all about torque. Plus, since they were the only setup available years ago, they are more readily available for cheap. It usually means I have to rebuild them, but that's what I enjoy doing, so it all works out well.

tyhuck

Ok JohnnyB, here is what I came up with. I like the nice easy takeoff and the increase of speed is comfortable. I also feel much better with my kids and wife driving it with the throttle less touchy at takeoff, but I am curious if it matters that the torque curve is lower than the speed curve. Does this matter? The speed curve is the one set up by ScottyB, and he already had the throttle set at 12.5%. I just want to make sure that I am not going to hurt anything with my settings.

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JohnnieB

I'm not sure how the speed and torque curves interact, but I don't think it harms anything to have speed lower than torque or torque lower than speed.

There is another throttle setting that is user adjustable, but you have to go into the tools menu at the top of the page to get access to the Throttle Linearization page.

Throttle Linearization is how the controller interprets the pedal's physical position and you can adjust it so the first portion of pedal travel has less effect the last portion. In other words, the first inch of pedal depression does open up the throttle as much as the last inch of travel, or it can be set up just the opposite or anywhere in between.

Attached is the throttle linearization curve I use. I can physically push the pedal halfway down and the controller interprets it as 30% throttle being called for. That gives me more pedal travel to play with when maneuvering in tight places and allows me to take off on wet grass without spinning the tires.

The throttle linearization curve supersedes the speed and torque curves.

Basically, you have to experiment a bit to get the Throttle Linearity, Throttle Speed and Throttle curves plus the Throttle Rate slider tweaked in to your liking.

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