How to diagnose and fix a parasitic draw in your golf cart

how to diagnose parasitic draw on your golf cart battery

Picture this: you’ve been eagerly planning a day on the green, envisioning the perfect swing and smooth ride in your trusty golf cart. But as you head to the course, you realize something’s wrong. Your cart’s battery is drained, stranding you in a sea of dim hopes. 

This condition is a parasitic draw— mysterious power drainage even though the golf cart ignition is off.  As a cart owner, you should know how to diagnose and fix a parasitic draw on your golf cart battery. 

This article will discuss the symptoms of parasitic draws, how to diagnose and fix the problem, and how to prevent it from happening again. Get ready to wield the diagnostic tools like a pro and regain power over your golfing escapades!

What is a Parasitic Draw?

Parasitic battery drain, also known as a parasitic draw, occurs when an electrical component or circuit in a vehicle draws power even when the engine is off.

If left unchecked for an extended period, this can result in a dead battery. Interior lights, radio systems, and alarm systems are common causes of parasitic drains. Identifying and addressing these battery discharges will ensure reliable operation and prevent unexpected failures.

What are the Symptoms of Parasitic Drain

If your golf cart is experiencing a parasitic draw, you may notice the following symptoms:

  • Battery drainage, even when the golf cart is not in use
  • Difficulty in starting the golf cart
  • Electrical components like lights, a weak horn, or the radio are not working properly.
  • Flickering headlights or interior lights.
  • A strange sound is coming from the electrical system.
  • An overheated battery after a drive may indicate parasitic draws that cause it to work too hard.
  • The presence of corrosion or other damage to electrical components may indicate a parasitic draw causing the system to wear out more quickly.

Pay attention to any unusual behavior from your golf cart’s electrical system, which could indicate a parasitic draw.

How to Diagnose Parasitic Draw on Your Golf Battery

To unmask the parasitic draw and restore your cart’s battery to its full glory, you’ll need to play the role of a detective. Here’s your arsenal of diagnostic steps to get started:

Visual Inspection:

Begin your investigation by examining the golf cart’s electrical components. Look out for any frayed wires, loose connections, or signs of corrosion. These visual cues can provide valuable clues about potential trouble spots.

Disconnecting Accessories:

Sometimes, aftermarket accessories can be the prime suspects behind a parasitic draw. Disconnect all additional equipment, such as sound systems, lights, or USB chargers, and observe if the battery drain issue persists. This step helps eliminate any potential culprits outside the cart’s original wiring.

Amperage Measurement:

Now it’s time to unleash the power of amperage measurement tools. Connect a multimeter in series with the battery and observe the current flow when the cart is at rest. Ideally, a healthy golf cart should draw minimal current, typically less than 50 milliamps (mA). Anything beyond that could indicate a parasitic draw.

Isolation Technique:

You must perform the isolation technique to pinpoint the exact circuit responsible for the parasitic draw. Start by removing one fuse at a time while monitoring the amperage reading. If the reading drops significantly after removing a particular fuse, you’ve likely discovered the pesky circuit that demands your attention.

Which Parasitic Draw Test Method Is Really The Best

Different options are available to test parasitic draw. Testing parasitic draw with a multimeter is the best method. 

Parasitic Draw Test with Multimeter: Connecting the Digital Multimeter

Parasitic Draw Test with Multimeter: Connecting the Digital Multimeter

To begin our quest for the elusive parasitic draw, we must ensure our golf cart is ready for testing. Here’s how to get started:

Preparing Your Golf Cart

Before connecting the digital multimeter, ensure all electrical components in your golf cart are unplugged or turned off. This includes the radio, lights, air conditioning, windshield wipers, and other accessories that may draw power. Engage the emergency brake, turn off the cart, and remove the key from the ignition. Close all doors and compartments to deactivate any active circuits.

Charging the Battery

For accurate testing, starting with a fully charged battery is crucial. Pop open the hood and locate the battery. Connect a reliable vehicle battery charger and bring it to a full charge. This ensures we have a solid foundation for our parasitic draw investigation.

Disconnecting the Negative Battery Cable

To prepare for the multimeter connection, locate the negative battery cable. It’s usually marked with a minus sign (-) and may have a black cover. Remove the cover, if present, and use an appropriate wrench to loosen and disconnect the negative cable from the battery terminal. This ensures we can isolate the circuit and accurately measure any parasitic draw.

Setting up the Digital Multimeter

Now, let’s introduce our trusty sidekick, the digital multimeter. This versatile tool will help us detect and measure any parasitic draw. Set up the multimeter by connecting the black wire to the “com” (common ground) input and plugging the red wire into the highest amp input, typically labeled as 20A. Adjust the dial on the multimeter to the amp measurement mode.

Attaching the Multimeter

With the multimeter set up, it’s time to make the crucial connection. Place the red lead through the metal circle at the end of the negative battery cable and touch the black lead to the negative battery terminal. You can secure the leads using plastic clamps for convenience and uninterrupted measurements.

Analyzing the Reading

Now, let’s see what the multimeter reveals. A parasitic draw within the range of 20 to 50 milliamps is considered normal since certain vehicle components, like the radio clock, requires a small amount of power at all times. However, if the reading exceeds 50 milliamps, it indicates a parasitic draw. This means something consumes excessive power and drains your golf cart’s batteries.

Can it be the Fuse?

With the multimeter in place and a parasitic draw confirmed, it’s time to narrow down the source of the drain by checking the fuses. Here’s how to proceed:

Removing Fuses

Locate the fuse box under the hood of your golf cart. Use a fuse puller to remove the fuses one by one, starting with those with the lowest amp ratings and progressing to the higher ones. After each fuse removal, monitor the multimeter reading to detect any significant changes. If the reading remains unchanged, replace the fuse and move on to the next one.

Observing the Significant Drop

Watch for a notable drop in the multimeter reading as you remove fuses. A significant drop indicates that the circuit associated with the removed fuse is responsible for the parasitic draw. Once you observe this significant change, you’ve found the electrical circuit causing the drain, bringing us one step closer to solving the mystery.

Identifying the Culprit

To pinpoint the exact component causing the drain, consult the fuse box chart or your golf cart’s owner’s manual. These resources will provide valuable information about the components powered by the fuse associated with the drain. Additionally, referring to the battery wiring diagram for the specific circuit can help further narrow down the problem.

Component Inspection

With the culprit circuit identified, it’s time to inspect the devices or components connected to that circuit. Start by replacing the fuse and then disconnect each lamp, heater, or electrical device one at a time. Don’t forget to toggle the switches corresponding to these components. As you disconnect and toggle each element, closely monitor the multimeter reading. When the reading drops, you’ve found the specific component responsible for the parasitic draw.

Repairs and Reconnection

Once you’ve identified the problematic component, it’s time to address the issue. Depending on the nature of the problem, you may need to repair or replace the component. If you’re confident in your skills, proceed with the necessary repairs. However, for complex issues or if you’re unsure, it’s advisable to seek assistance from a certified golf cart mechanic. After making the repairs, verify that the multimeter reading remains below 50 milliamps. Finally, disconnect the multimeter, reconnect the battery cable, and get ready to cruise on your revitalized golf cart!

Other Ways to Fix Parasitic Draw on Your Golf Cart Battery

With your detective skills put to good use, it’s time to bring the parasitic draw culprit to justice. Here are a few common scenarios and their corresponding remedies:

Faulty Switches

Defective switches can cause an unintended current flow, leading to a parasitic draw. Replace any faulty switches, such as the key switch, forward/reverse switch, or other circuit-specific switches, to restore electrical harmony.

Worn Wiring

Over time, wiring can become worn or damaged, creating intermittent connections and unwanted electrical pathways. Inspect the wiring harness thoroughly and address any signs of wear, including exposed or frayed wires. A little re-wiring magic can go a long way!

Troublesome Components

Certain components, such as voltage regulators, solenoids, or controllers, can also be the secret culprits behind your cart’s battery drain. In such cases, it’s best to consult a professional golf cart mechanic to diagnose and replace the troublesome part.

How to Prevent Parasitic Draw on Your Golf Cart Battery

Here are some steps you can take to prevent parasitic draw in the future:

Regular maintenance

You can prevent parasitic draws on your golf cart with regular maintenance. Check for loose or corrosion-ridden connections, inspect electrical components for damage or wear, and make sure all aftermarket accessories are installed correctly.

Proper storage

Golf carts should be stored properly when not in use. These steps include disconnecting the battery or using a battery disconnect switch, keeping the cart dry and secure, and covering it to protect it.

Learn more about storing the golf cart in the winter

Upgrading to a smart charger

Investing in a smart charger will prevent parasitic draws and extend the life of your batteries. Using smart chargers, you can prevent overcharging and reduce the risk of causing damage to your battery by automatically monitoring and adjusting the charging process.

Following these preventative measures will help you maintain the health of your golf cart battery.


The parasitic draw is a common issue that drains your golf cart battery and causes problems starting it. The steps outlined in this article will help you diagnose and fix the issue and prevent it from happening again. Golf cart batteries require regular maintenance and proper storage to remain healthy. It is recommended to seek professional assistance if you need help with diagnosing or fixing the issue.

Picture of Van Douglas

Van Douglas

Van Douglas is a seasoned golf enthusiast and skilled writer, delivering informative and engaging articles on his blog that capture the essence of the sport with expertise and passion.

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