What Is The Typical Parasitic Load On A Car Battery?

When it comes to complex circuits that have an extensive network of loads running through a battery, having a parasitic load can be a problem. Having a lot of it can be a huge problem because it can drain the battery a lot faster.

Defined as systems or loads connected to a cell that draws unnecessary power for operations that you don’t really need.

This mostly happens in cars, especially the modern models that are reliant on sophisticated or advanced electronics. What makes the parasitic load a problem is that the more these loads consume power, the faster they drain the vehicle’s battery.

What is a parasitic load on a battery? As defined earlier, a parasitic load on a battery is a resistance that continuously drains the cell or consumes energy even after the circuit is shut down.

In vehicles, a parasitic load is defined as an electrical load that causes an abnormal power discharge on the battery even when the engine is turned off.

It is usually caused by an electronic device left on after the car engine was killed or a short circuit within the car’s electric grid.

Later model cars have an average of parasitic power draw within the range of fifty milliamperes to eighty-five milliamperes due to more electronic devices.

In comparison, the average parasitic draw on older model cars is less than the fifty milliamperes average. Not only in cars, but parasitic loads on batteries can also be present in smartphones and any circuit powered by a battery.

If a circuit has multiple loads and runs through a battery as its power source, any resistance that continuously draws power from the power source even after the circuit is shutdown is considered a parasitic load.

However, this is mostly observed on vehicles since it can be a problem for drivers and car owners.

As I mentioned earlier, having parasitic loads is one of the most common problems drivers or car owners. That is why this article is mostly centered on parasitic loads or power draw on automotive batteries.

If you are one of those car owners noticing excessive battery drain on your car’s battery, you may want to stick around cause it may be due to parasitic loads.

The Severe Effects of Parasitic Loads to Automotive Batteries

Now that we’ve defined a parasitic load on a battery, you now have an idea that it is a problem haunting drivers and car owners. To better understand the harmful effects of parasitic power drain, we are going to dig deeper and learn more about the danger it poses to a car battery.

A simple emphasis on how parasitic loads can be dangerous to car batteries is that these milliamperes considered as a parasitic draw can kill a car battery.

Keep in mind that it can significantly impact battery life because having these loads can take up the current that the battery should receive from the alternator. This prevents the cell from being recharged.

You also have to keep in mind that even the usual or reasonable parasitic power draw, which is commonly referred to as the “key-off power drain” can stress the battery.

Significantly contributing to its wear and tear of the daily grind. This is because sulfation is triggered when the voltage of the cell drops down below the 12.4-volt rating. And we all know that sulfation is considered as one of the top battery killers.

Parasitic Loads: How to Find What Causes Parasitic Drain

You now realize how nasty and bad these parasitic loads can be to your battery, but fortunately for us, they are easy to find.

With a reliable and accurate multimeter designed for vehicle use, you can determine these loads that may lead your battery to its early demise. Suppose you are to carry out a search for these parasitic load, here are the steps that you have to follow.

Step 1: Make Sure to Consult the Vehicle’s Manual and a Mechanic

Before carrying out your search for the culprits of parasitic drain that can harm your battery, you first have to consult your car’s manual or a professional mechanic.

Keep in mind that there are electronic devices designed to draw a small amount of current from the battery. Electronics needed to ensure optimum performance, and these are considered as necessary and essential parasitic loads.

Vehicle components like oil pumps, driveshafts, valve springs, etc. are among the contributors to a car’s standard parasitic loads.

You first have to be familiar with these components; otherwise, you may be misleading and terminate some of them that may compromise your car’s performance.

Some of these components are equipped with batteries to power them and recharged by the alternator. But some don’t, and they are among the components making up the standard parasitic drain on your battery.

Step 2: Verifying the Presence of Parasitic Load on the System

After getting familiar with the necessary parasitic loads essential for the performance of the car, the next thing you have to do is verify if there are loads in the system, causing the parasitic drain.

This is done by shutting down the engine of the car and then connecting the automotive multimeter with the negative terminal of the battery. And then linking the other cable of the meter with the wiring of the car or its electrical grid.

Wait for the multimeter reading and see if the voltage is still being drawn from the battery. If there’s voltage drawn, it indicates that the car has parasitic loads.

Step 3: Carrying Out a Preliminary Search or Physical Inspection

Suppose you find out that the system has parasitic loads, conduct a physical search, or a preliminary inspection. Start by checking the cab and its surroundings to see if there are any electronic gadgets or devices that are still connected to the car’s power source.

The most common electronics left connected include USB chargers, GPS devices, and small electricals that are often taken for granted or forgotten. These are electricals that still consume power, draining the battery continuously.

Step 4: Conduct a More In-Depth and Intricate Search

After your preliminary inspection or search and disconnecting the electronics that are still connected with the power source. But you still have a parasitic drain. It is time for you to dig deeper by looking into the systems of the car.

In some cases, the parasitic draw comes from unnoticed electrical issues like short circuits or common problems with a trailer system, which is a necessary load.

When the vehicle’s trailer system is designed to close the circuit when the cell reaches the 100% state, it fails to close the circuit due to failure or damage. This prevents the circuit from closing and keeps on charging, which continuously draws power from the battery.

That is how you find the culprits of the parasitic draw on your car’s battery. Once you address those issues, you can now rest assured that your battery will always be in good shape.

Now that you know how to determine the parasitic loads. It will give you an idea of how you can get rid of them, or at least by knowing them. You can take the necessary steps to fix the issue.

Preventing Parasitic Draw by Avoiding to Have Parasitic Loads

We are all familiar with the saying that goes, “prevention is better than cure,” and when it comes to parasitic loads, it is very accurate.

Because once it delivered its toll on the battery’s health, amplifying its wear and tear on its daily grind. There’s a greater chance that the deterioration of the battery will be gradual until it dies.

Imagine, many unnoticeable parasitic loads slowly eating up your battery and being left unattended or unaddressed. It will surprise you all of a sudden, where you will frequently experience a failing battery.

The best way to prevent these parasitic loads from emerging on your car is to be a responsible car owner and better awareness.

Here are some good practices that you have to take note of:

Never Waste the Energy Stored in the Battery (Be Energy Efficient)

Being aware of the dangers parasitic loads pose to your car battery is not enough to prevent them. Awareness is just a state of mind. It will always require actions to be implemented.

One of the best ways of preventing these electrical leeches is by making sure to disconnect all electricals before shutting down your car’s engine.

Pull out all chargers, gadgets, and devices connected to the power source, and turn off all electrical components of the vehicle before leaving it.

If you notice on the information, we’ve gone through earlier. Physical, electronic devices and components are one of the biggest contributors to parasitic draw.

So making sure that all of them are disconnected will ensure that parasitic loads will only exist within the vehicle systems.

Adding Parasitic Load Checking or Monitoring on Car’s Upkeep

Including a parasitic load monitoring or checking on your car’s regular maintenance is also an effective way of preventing parasitic draw on the battery.

As you do your regular car maintenance, take time to check the parasitic load’s presence on your vehicle systems.

This will allow you to discover the unnoticeable loads causing parasitic draw due to electrical failures or issues, giving you the opportunity to fix them ASAP or seek professional help.