The BEST Way TO Perform a Parasitic Draw Test

Summary

This video tutorial explains how to measure parasitic current draw in vehicles effectively. The host demonstrates the process using a multimeter and emphasizes the importance of checking battery health before testing. Key steps include verifying multimeter leads, ensuring the car is fully asleep, and measuring voltage drop across fuses. By interpreting the readings with a provided chart, viewers can identify significant draws that could drain the battery. This method avoids common pitfalls associated with disrupting vehicle electronics, making it a practical approach for diagnosing battery drain issues.

Takeaways

• 🔧 Use a multimeter to measure parasitic current draw without disconnecting the battery.
• 📊 Checking the multimeter leads for accuracy is essential before starting the test.
• 🔋 Ensure the vehicle's battery is charged (around 12.6 volts) for accurate readings.
• 🚗 Lock all doors and latch the hood to allow the vehicle to go to sleep during testing.
• ⚡ Measure the voltage drop across each fuse to identify potential current draws.
• 📉 A reading that drops to zero across a fuse indicates no current draw; otherwise, further investigation is needed.
• 📋 Use a voltage drop chart to translate millivolt readings into actual current draw.
• ⚠️ Significant current draws can lead to battery drain; be vigilant for readings above specified limits.
• ⏱️ Checking fuses individually can be efficient; expect around 3-5 seconds for each reading.
• 👨‍🔧 Understanding vehicle electronics is crucial for troubleshooting complex issues related to current draw.

Q & A

What is parasitic current draw?

Parasitic current draw refers to the electrical current that continues to flow from the battery when the vehicle is turned off, which can lead to battery drain.

Why is it important to measure parasitic current draw?

Measuring parasitic current draw is crucial to identify any electrical issues that might cause a battery to drain unexpectedly.

What tools are required to measure parasitic current draw?

The main tools needed are a multimeter and voltage drop charts.

How should you check the multimeter leads before testing?

Set the multimeter to ohms and ensure it reads about 0.1 to 0.2 ohms. If readings are higher, the leads should be replaced.

What should you check regarding the vehicle's battery before measuring current draw?

Ensure the battery voltage is around 12.6 volts and that it can maintain a voltage above 10 volts when the vehicle is loaded.

What preparation steps should be taken before conducting the current draw test?

Close and latch all doors and the hood, lock the vehicle, and wait for 1-2 hours to allow it to go to sleep.

How do you measure voltage drop across a fuse?

Set the multimeter to millivolts and place a lead on each side of the fuse. Observe the reading; it should drop to zero if there's no current draw.

What does a voltage drop indicate when measuring current draw?

A voltage drop indicates that current is flowing through the circuit. The magnitude of the drop can help quantify the amount of current draw.

What should you do if a significant current draw is detected?

If a significant draw is found, it may indicate an issue with the circuit, and further investigation is required to identify the faulty component.

What common mistakes should be avoided when measuring parasitic current draw?

Avoid pulling fuses as it may disrupt the vehicle’s electronic systems, and ensure the multimeter is functioning properly to avoid inaccurate readings.