golf Carts Unlimited
Sepex drive carts have gained 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 speeds up to 25 mph.
The Sepex drive system consists of 9 to 11 cables depending upon the battery configuration.
No F&R mechanism upgrade is needed as the controller does the high amperage switching for directional changes.
A typical upgrade consists of a speed controller, a solenoid, and the cable set.
400 amp control & a 200 amp solenoid is suggested for a stock motor
500 amp control and 400 amp solenoid is suggested for aftermarket and custom-built motors.
Use 4 gauge cables with 400 amp controls and 2 gauge cables with 500 amp controls.
Keep in mind that bigger tires and added weight adversely affect the golf carts performance.
A change in tire size equals a change in final gear ratio. Gear ratio changes directly influence the amount of load put on the motor and drive system. A 20% increase in gear ratio will equal a 20% loss of torque or power. I suggest 20 to 22 inch tires for all upgrades.
Getting too big of a tire is a common mistake.
Picture yourself pushing a small tire up a hill.
Now picture yourself pushing a much larger tire up the same hill
We are going to look at series drive carts first. Initially all golf carts were series drive.
Sepex drive carts came later. The series drive carts are known as the workhorses of the golf cart world. Series carts produce more torque and less speed than their Sepex drive cousins. They are the first choice for off-road use and towing.
The most common upgrades with these carts include a bigger speed control, a larger solenoid, a heavy duty forward and reverse switch, and the cable size upgrade.
There are 13 or 14 high amperage cables in a series drive. The high amperage passing from the battery pack to the motor goes through all 13 or 14 of these cables when you ask the cart to go. All of these cables and every component they are connected to need to be upgraded when putting in a larger speed control.
The reason for this is that the larger speed control will allow the motor to draw more amperage and that amperage is going to flow through the entire system. If one component is left stock in an upgraded system it will soon fail.
The first step in upgrading your golf cart is determining which drive system it has.
There are two types of drive system used in golf carts.
Use the flowcharts below to determine if your cart is Sepex or Series drive.
Sepex cart Upgrades
Golf Cart Parts and
Golf Cart Accessories
400 amps = 200 amp solenoid & 4g cables
500 amps = 400 amp solenoid and 2g cables
700 amps = 400 amp solenoid and 2g cables
A heavy duty forward and reverse switching device is suggested with all controller upgrades.
Keep in mind the original 2 to 3 hp motor was designed to take two passengers down the fairway for game of golf. If your use is very different from this then you will need a custom aftermarket motor to produce enough horsepower to achieve the performance needed.
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 but it will not increase top end speed - more voltage will increase the stock motor rpm.
42v will increase motor RPM by 17.5%
48v will increase motor RPM by 33%.
You will have to upgrade the controller and solenoid in order to be able to run 48v. The stock motor can run on 48v.
Aftermarket motors built for more torque or more speed or a combination of both torque and speed are available.
My recommendations are based upon what I have learned from upgrading 5 to 6000 golf carts over the past decade. These upgrades were used everywhere from beachside parks to the Colorado Rockies. Many of our customers enjoy hunting and off-road exploration with their golf carts. Most of these carts are lifted with big tires and seating for additional passengers or cargo boxes. This creates the ultimate challenge for a simple battery-powered golf cart.
Many of these carts were also upgraded for neighborhood use where the need for speed is the call of the day.
Series cart Upgrades
Stock golf cart controllers range from 225 amps to 300 amps in size.
400 amps increases available amperage by about 25%
500 amps increases available amperage by about 40%
700 amps increases available amperage by about 60%
400 amps is good for bigger tires and additional seating on flat ground.
500 amps is good for bigger tires and additional loads where hills and soft terrain is involved. note: 80% of all upgrades fall into the 500a category. 500 amp controls are good when used with the factory motor and with most aftermarket motors. Our 500 amp controller packages include the 400 super solenoid which will run on 36 volts now and 48 v later. This is a very popular combination for users who want to upgrade voltage later.
700 amps is good for the biggest aftermarket and custom built motors.
First identify drive system.
Is it Series or Sepex ?