Sepex cart upgrades 

what to do 


what to expect 

Bigger speed controls, solenoids, & motors

About voltage

A bigger speed control will allow the motor to access more amperage. The motor will use this additional amperage to make more torque which will help in the power department.

The Alltrax XCT speed controller will raise the rpm limits imposed by the stock controllers. 

In most cases a simple controller upgrade will increase top speed from 14 to 22-23 mph.

And in many carts this simple controller upgrade will also increase power by 30% over stock. It's a win -win situation with more power and more speed. Larger cables will allow more amperage to flow more quickly to the motor, this can enhance  the controller upgrade. 

But keep in mind that the amount of power a motor can make is limited by design.

A typical  stock 2 - 3 hp motor can only produce 2 - 3 hp.

Bigger aftermarket motors built for more torque or more speed or a combination of both are available.  The ultimate upgrade includes an upgraded motor too.

Keep in mind that big tires and added weight can adversely affect the golf carts performance.

A change in tire size is a change in the final gear ratio. Gear ratio changes directly effect the amount of load put on the motor and amperage delivery system. A 20% increase in gear ratio will equal a 20% reduction of torque or power.

Getting too big of a tire is a common mistake.  Stock tires are 18 inches in diameter. 18" tall.

Total tire diameter is what we are concerned with here NOT RIM SIZE.

I suggest 20 to 22 inch tires for all upgrades. If we have 2 identical carts, one with 20" tires and the other with 24" tires. The cart with the smaller tires will have 20% more power.

Size Matters

Sepex drive carts have gained tremendous popularity as neighborhood vehicles.

Moderate upgrades are inexpensive and produce speeds between 20 and 24 mph. 

Carts with Sepex drive systems excel at zipping around the neighborhood. They can be modified for off-road use but they are in their best element as people movers. 

A simple aftermarket control can increase torque by as much as 35%

and release the motor RPM limit resulting in significant speed increases.

The Sepex cart can be set up for off road use. Pay attention to details. Bigger tires and off road activity will significantly increase the cart's workload. Upgrade the complete drive system with controller, solenoid, cables, and motor for the best results.

Motor mapping is important. Motor maps from Alltrax are available for every popular motor today.  Some motors have more than one map available .. like one for speed (street use) and one for torque (off road use). Speed and Torque are in constant trade off in the electric motor.

Field maps are available for all stock motors as well. 

One word of caution now. Extended periods of slow operation, especially with big tires or in hilly terrain will cause the sepex motor to over heat. If this is your need consider a series drive cart which is more tolerant in this area.

We will install the map of your choice before we ship. Thank you for reading this. Consider yourself qualified to make educated upgrade decisions  based upon the information above.

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Sepex carts have a toggle switch F&R device. There are light wires connected to the F&R switch and the motor has a pig tail of wires.

These carts have a run / tow switch which cuts power to the controller.  

There are 10-26 small wires connected to the speed controller.

Sepex carts are people movers and often serve as NEVs

Not as well suited to slow and heavy work as series.

Sepex cart Upgrades

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Most all modern carts have Sepex  motors.

SepEx controllers have control of both the armature voltage and the current on the motor field coil. This offers more dynamic control of the motor.

We see this dynamic control as regenerative braking and rpm or speed limit.

The Sepex motor produces more speed is more efficient than it's series cousin.

The sepex motor is best  suited for a neighborhood electric vehicle.

in Conclusion

Early sepex carts were 36 volt systems. Today almost all carts are sepex drive and 48 volts. 

The higher voltage is more effective and more efficient. Meaning the carts make more power and run longer on higher voltage.  

If you are upgrading a 36v sepex cart consider going up in voltage too.  For the 36v Ezgo DCS or PDS add a 7th 6v battery and run the stock motor on 42v. Or spring for an aftermarket motor like the Admiral MOT-B2 and run 48v just like the new carts.

Higher voltage will produce more speed and torque.

6/8v batteries fit in the original battery trays.

Stock golf cart controllers range from 225 amps to 300 amps in size.

400 amps increases available amperage by about 50% over stock
500 amps increases available amperage by about 70%

The Alltrax  XCT controller has higher peak and sustained output than any competitor.

See 10 features that make this controller the best choice for your golf cart HERE

300 XCT has a peak output of 350 amps. This is the perfect upgrade for carts on hard flat streets that just want a little more acceleration and speeds up to 22-23 mph. This controller works with the stock solenoid and wiring.

400 XCT has a peak output of 460 amps. This is the most popular upgrade size for carts on hard flat streets that just want a more acceleration and speeds up to 22-23 mph. This controller allows the stock motor to make all the power it can. This makes it a good choice for moderate off the road activity with bigger tires. And a good choice for carts with rear seating for added passengers too. This controller requires a bigger 200 amp solenoid and amp delivery is improved by an upgraded cable set. 4g is okay and 2g is better. We use 2g cable sets for everything. Both stock and aftermarket motors are okay with the 400 amp controller.

500 XCT has a peak output of 570 amps. This is the a popular size for carts used on & off the streets with big tires, rear seats, and aftermarket motors.  Expect more acceleration and higher speeds especially with bigger motors and taller tires.

The 500 amp controller is too big for the stock sepex motor. We can turn the controller down to 400 amp specs for the stock motor. The user can then turn the controller up when they get a bigger motor. The software is free and easy to use here >  Alltrax Toolkit 

The XCT 500 includes a cooling fan and requires a 400 solenoid and 2g cable set.

This makes the 500 the right choice for off the road activity with bigger tires and bigger motors.