Low Speed Electric Vehicles (LSVs) 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. Three-year-old Club Cars, EZ-Gos and others turn up by the thousands at auctions across the US each year. Some end up in neighborhood classifieds or used car lots after a quick makeover. Many of them head to “junk shops” where they are stripped of their original golf paraphernalia, jacked up, outfitted with flashy wheels, carbon-fiber dashboards, plush upholstery and satellite radios. They have painting themes that range from your favorite adult beverage to your alma mater team and more. A $1400 golf cart magically transforms into a $6,000 “pride ride” for one lucky consumer.
The only thing the fabulous makeovers these vehicles often have in common is old batteries and components. The other thing is; they are usually set to operate at really slow speeds (12 mph or so). You who have rented golf carts at your local course know why you do it. 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 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, wait a few weeks.
Okay, so you’re ready to do whatever it takes to make that baby fly. Okay, maybe 20mph isn’t exactly flying, but it sure will feel like you are if you get thrown around 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? Will you be carrying cargo of any substantial weight (No, I’m not referring to 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 use it mostly on flat ground, you have a few more options:
• taller tires – Increasing the diameter of the drive tires increases the distance they will roll for each revolution of the axle, thus increasing the speed at which your cart will go. You first 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 to help you determine how much speed you’ll gain with the new taller tires. A very good one is found 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! Tire size is also limited by the opening of the wheels. Most large tires require the cart to be “lifted”, which is not always desirable and can be expensive. Speed gain is relatively small (an increase of a couple of mph)
• High speed gear set – In the differential box or rear axle, a gear reduction system resides. The motor has a small gear that drives the larger gear on the shaft. Typically, the motor rotates about 12 times for each revolution of the shaft. This is how the relatively low horsepower motor gains a mechanical advantage to propel the car. Like the gears on a bicycle, it’s easier to pedal when the drive sprocket is in the small diameter. To go faster you need to advance 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 mountainous areas. Installation can be tricky due to gear lubricant 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 mod doesn’t sacrifice low-end torque like the two mentioned above. Golf cart electric motors are designed to operate at a certain maximum RPM (typically around 3600 RPM) at 36 or 48 volts and provide a good balance between speed and torque in the end product. Aftermarket engines have their field and armature windings redesigned to reach higher RPMs than stock. If the motor 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 at 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 cars called SpeedyLink, which increases the RPM of the original engine by about 50% without additional modifications.
Whatever method you use to increase the speed of your golf cart, be sure to use good judgment and use the proper safety equipment. Karting can be fun and functional for everyone and has many applications. Be safe enjoying your fast golf cart. Keep an eye out for more articles on golf cart upgrades and maintenance.