Low Speed Electric Vehicles (LSV) are becoming wildly popular these days for a number of reasons. They’re quiet, fun, and relatively comfortable to drive, but most importantly, they don’t use fossil fuels. However, newer LSVs like the GEM and others can be very expensive and are not a practical purchase for those who would only use them occasionally or on weekends. Welcome Golf Course Fleet Vehicles (Golf Carts) to the rescue, Out of Warranty. Club Car, EZ-Go and other three-year-olds appear by the thousands at auctions across the US each year. Some end up in neighborhood classified ads or used car lots after a quick makeover. Many of them head to “junk shops” where they are stripped of their original golf paraphernalia, given a lift, outfitted with flashy wheels, carbon-fiber dashes, plush upholstery and satellite radios. They have paint themes ranging from your favorite adult beverage to your alma mater team and more. A $1400 golf cart is magically transformed into a $6,000 “pride ride” for one lucky consumer.
The only thing the fabulous makeovers these vehicles often have in common are old batteries and components. The other thing is; They are usually set up to operate at really slow speeds (12mph or so). Those of you who have rented golf carts at your local course know why. To operate on public roads and be categorized as an LSV, many municipalities require the vehicle to go 20 mph and must be equipped with lights, seat belts, and a horn. The lights and seat belts are easy enough to manage, but getting your cart to go 20 mph is another story. Even if you’re not trying to make it street legal, most users want the extra speed capability just to add more utility and enjoyment. 12 mph is too slow for most users. If you think 12 mph is fast enough, give it a few weeks.
Good, so you’re ready to do whatever it takes to make that baby fly. Well, maybe 20 mph isn’t exactly flying, but it sure will feel like you are if you’re thrown at that speed. Seat belts are a good idea at any speed. The first thing to determine is how fast you really want to go and how you are going to use the vehicle. Is the terrain flat or hilly? Are you going to carry cargo of any substantial weight (No, I don’t mean your mother-in-law)? For slopes and/or heavy loads, you will also need to increase the torque of the trolley. This means a more powerful motor and probably an improved motor controller to handle the additional current demands of the motor. There are several vendors that can provide such updates, but they can be expensive. Be sure to do your homework and shop around. If you only have a standard cart and are basically using it on flat ground, you have a few more options:
• taller tires – Increasing the diameter of the drive tires increases the distance they will roll per axle revolution, thus increasing the speed your cart will go. First you need to know how fast you can go on the standard 18.5-inch-tall tires. Most portable GPS units can be used as a speedometer to find that. If you don’t want to do the math, there are several free online calculators that will help you determine how much speed you will gain on the new taller tires. A very good one is on the Digital Overdrive Systems website. Although increasing tire size will increase speed, torque will suffer a bit. That means you may have to leave your mother-in-law’s house! The size of the tires is also limited by the opening of the wheels. Most large tires require the car to be “jacked up” which is not always desirable and can be expensive. The speed gain is relatively small (a couple mph increase)
• high speed gear set – In the case of the differential or rear axle, resides a gear reduction system. The motor has a small gear that drives the larger gear on the shaft. Normally, the motor rotates about 12 times for each revolution of the shaft. This is how the relatively low horsepower engine gains a mechanical advantage to propel the car. Like the gears on a bicycle, it is easier to pedal when the drive sprocket is on the small diameter one. To go faster you need to move up to the larger drive sprocket. The bike goes faster, but it’s harder to pedal. In a golf cart speed gear set, the ratio is similarly changed by increasing the diameter of the drive gear and the cart runs faster. However, just like the bicycle, the motor has to provide more force “torque” to the axle. This type of mod is great for speed, but will sacrifice low-speed torque (your mother-in-law again) and is not recommended for hilly areas. Installation can be tricky due to gear lube and requires some skill and knowledge.
• Increase Engine RPM – Increasing the revolutions per minute or RPM of the engine is one of the most popular techniques to increase the speed of a golf cart. This type of modification does not sacrifice low-end torque like the two mentioned above. Electric golf cart motors are designed to operate at a certain maximum RPM (typically around 3600 RPM) at 36 or 48 volts and provide a good balance of speed and torque to the end product. Aftermarket motors have their field and armature windings redesigned so they reach higher RPM than stock. If the engine spins at twice the original RPM, a 12 mph cart could go up to 24 mph. The motors are safe and reliable, but may require the addition of a high current driver to operate to their full potential. Aftermarket “speed motors” are available through various vendors, but can be quite expensive due to all the copper wire in the windings. There is a vendor that provides a really simple and easy upgrade for Club Car IQ carts called SpeedyLink, which increases stock engine RPM by about 50% without any additional modifications.
Whichever method you use to increase your golf cart speed, be sure to use good judgment and use the proper safety equipment. Karting can be fun and functional for everyone and it has many applications. Be sure to enjoy your fast golf cart. Stay tuned for more articles on golf cart upgrades and maintenance.