How to check parasitic current drain of battery in a vehicle

To check the parasitic current drain of a battery in a car, you will need a digital multimeter and some basic knowledge of how to use it.

Here is the generalized prodcedure

1. Turn off all electrical devices in the car, including the radio, headlights, and interior lights.

2. Remove the negative cable from the battery. This will prevent any electrical current from flowing through the car's circuits.

3. Set your multimeter to measure DC amps. Most multimeters have a setting for this.

4 Connect the multimeter's positive lead to the negative battery terminal and the negative lead to the negative cable that you removed in step 2.

5. Wait for about 20-30 minutes to allow the car's systems to power down completely.

6. Look at the reading on the multimeter. It should show the amount of current flowing through the car's circuits. Typically, the parasitic current drain should be less than 50 milliamps (mA). If it's higher than that, there may be a problem with one of the car's systems that is causing excessive current drain.

7. If the parasitic current drain is too high, start by removing fuses one at a time to see which system is causing the excessive drain. Once you find the culprit, you can investigate further to find the root cause of the problem and fix it.

8. Once you have finished checking the parasitic current drain, disconnect the multimeter and reconnect the negative cable to the battery.

It's important to note that checking the parasitic current drain is just one part of diagnosing battery issues. If you are experiencing problems with your car's battery, it's always best to consult a qualified technician who can perform a more comprehensive diagnosis.