72Volt controller question for the experts

Gem experts, where I live is a desert when it comes to GEM cars. I have a question about 72V controllers that the golf cart hobby world doesn’t focus on but you guys do all the time. Looking at a 72 volt AC (9-8v bats) drive Cushman dump cart. It has a 16kw (22hp) motor, 17:1 rear and 20" tires. When asked about swapping the controller, the golf cart community over at BGW doesn’t say much other than “get the guy in the southeast to reprogram it”. That would be great if he wasn’t 10 hours away and any time I wanted to make a change it would involve 2 days of travel. I would like to get a controller that I could tweak when I want too. It sounds like a great setup for the motor and rear, just need help on what I should swap to get it above the stock ~15mph settings.

For you motor/controller swap experts, any advice you could share? My ultimate goal is to go lithium once the FLA’s wear out.
I appreciate any and all feedback. Thank You!

What controller does it have and what is wrong with it?

It sounds like your cart is made as more of a hauling/service vehicle.
What is your intended use for the cart?

Can you find out anything more about the motor? What is it’s rated max RPM?
It sounds like that motor is huge. Probably a lot of rotating mass.

20" wheels and a 17:1 trans may not produce eye watering speeds.
The math shows
4k @ 14mph
5k @ 17.5 mph
6k @ 21 mph
7k @ 24.5 mph
8k @ 28 mph

This is NOT saying your motor will do anything more than 6k without scattering its bits.

Being positive- anything can be swapped. Its only work and a bunch of cash. It might be kinda fun to see a Cushman Dump Truck on a set of 26 in wheels.

@Inwo , it is a Curtis 1236 controller. At the moment there is nothing wrong with it. I am just being told that you have to work some magic to get the low level VCL programmed. Word on the street is the handheld controller people use only changes a high level value or two and prevents it from being changed at the lower VCL level once that high level value is changed. I don’t know enough about it yet to know if that is a fact or not. These motor/controller combo’s are capable of 35-40 mph in the EZ-GO L6 carts and the Cushman is the exact same setup. If I had a way to program it and some direction, I would be good to go.

@AssyRequired , The stock AC motor is limited to 12,000 rpm. Factory programming on these carts is 4500 rpm. This keeps the speed right around 15ish mph. There is a LOT of room to improve. But if I can’t program the controller, I would need to swap it for something I could control.
My end goal is to have a turtle/rabbit switch that would allow 15mph in turtle and around 30mph in rabbit.

Ah! I didn’t see that it was AC. I was thinking this was an old DC cart.

Have at it then.

Nothing wrong with Curtis controllers. Much easier for dig than the Sevcon that we use.
I believe Curtis is limited in rpm by the encoder speed, but you can certainly run you car faster than what’s safe.
Is your controller limited, for sure? Have you tried raising the speed limit?
My Miles truck Curtis was limited, but no reason to think they all are.
Having it reprogrammed makes the most sense. Take it out and send it in.
I don’t do Curtis, but may have access to sw.
On the other hand, if you want to start over. We will help you switch the Sevcon. We run at 9000rpm all the time. Your looking at $1200. A new Curtis should be no more.

Inwo, my understanding is that there are a couple of high level options that can be set to allow for a 19mph top speed that can be done with a Curtis handheld programmer at just about any dealer or even rented off the Internet.
I am being told those are just a few basic commands but the real configuration is in the Curtis OEM access level and this will allow configuration for torque, motor speed, regen braking, throttle “tip in”, etc. I found this: 1314-4402 | CURTIS PC Station Programmer with 1309 USB interface, OEM level programming tool, with full access to all parameters of CURTIS programmable controllers and devices. The CURTIS 1314-4402 is the newest upgraded version of CURTIS controller programming software 1314-4401.
but I am not sure if that is exactly what I need for access. If sending it to someone to reprogram is possible, where can I send it in to have it reprogrammed? I wasn’t aware that was even an option. Is there a service center that will reprogram it (or an individual) that would program it at the VCL level with the parameters I want? I don’t mind paying for the service. I was told that it had to be “in the cart” by the guy everyone recommends in Tennessee but that was because he doesn’t have a way to keep the controller properly powered during the writing of the config.

Anyway, this is a very long way of saying, if there is someone you know or a way to send it off and have it reprogrammed to my preferences, I would love to hear about it and be grateful for the guidance.

If they are correct that it can be done with an oem handheld, it’s easy.
I don’t do Curtis but do have a handset that is oem level.
If you want I’ll set rpm to maximum for you. That may be 4500 though. Know idea until I try. If it works, you can get a programmer yourself. If not, it will need to be reflashed to a non oem configuration to open everything up. Or buy a new controller. Selling your controller should recoup 1/2 the cost.
If someone can’t program on the bench, I would not have much faith in their advice or abilities. There is a Curtis guy on here bit he’s a known crook and head case.