Ah, the all-too-familiar sound of a car refusing to start, the disappointing click when you turn the key, the silent scream of despair as you realize your car battery is dead – again! If you find yourself constantly asking “Why does my car battery keep dying?” you’re in the right place.
Your car battery is more than a little box with a positive and a negative terminal. This automotive powerhouse gives life to your vehicle by supplying electrical energy which is needed to start your engine.
So when this lifeline starts to die rapidly, it can be more than a minor inconvenience; it can disrupt your life. But don’t worry… we’re here to shine some light on 7 common things that drain your car battery. Then we’ll give our some handy tips to prevent it from happening again.
1. Corroded Battery Connections
A buildup of corrosion on your battery terminals creates a barrier between the battery and the cables that transport power to your vehicle’s various electrical components. This corrosion can cause your car battery to work overtime to compensate for the lost power, draining it faster.
Getting ready to go to work & putting your key in ignition, only to find it doesn’t start is one of the most frustrating things. If you pop the hood and find a strange blue or greenish-white substance around the battery terminals – this is corrosion, and it’s draining your car battery fast.
2. Electrical Parasitic Drain
Did you know that your car battery can keep working long after you’ve switched off the engine and locked the doors? Electrical parasitic drains are the covert operatives of your car’s electrical system, sucking power from your battery when you least expect it. The usual suspects include the glove compartment light, the trunk light, and other electronics that continue to draw power even when the car is off.
Let’s say you drive home after a long day, park your car, then go inside to unwind. Unbeknownst to you, the light in your trunk stays on all night which ends up draining your car battery. Come morning time, you’re greeted with the unfortunate dead battery situation again.
3. Extreme Temperature Changes
Extremely cold weather can slow down the chemical reactions within your battery, reducing its ability to hold a charge. Extremely hot temperatures can cause your battery to overcharge, accelerating its demise.
Imagine a cold winter night. Your car is parked outside, subjected to the freezing temperatures. The battery, like a bear in hibernation, slows down and struggles to perform. The result in the morning… a drained car battery.
4. Battery Charging System Issues
Your car’s charging system is an unsung hero, ensuring your car battery is topped up while you drive. However, if there’s an issue with this system – perhaps a worn or loose alternator belt – it can fail to produce enough power to keep your battery charged while also handling other electrical components.
Think about it this way: Your car battery is like a jug, and the charging system is the tap filling it up. If the tap runs too slow or stops working, your jug won’t fill up, no matter how long it’s left under the tap.
5. Headlights Draining Vehicle’s Battery
Leaving your headlights on is an easy mistake to make and one of the most common reasons for a drained car battery. If you’ve ever come back to your car after a long day, only to find your headlights still brightly shining and your battery deader than a doornail, you know what we’re talking about.
Most modern vehicles have an auto-shutoff feature that turns off the headlights after 30 seconds to prevent this, but older models may lack this. If you have a habit of leaving your lights on, consider installing an aftermarket auto-shutoff device. And get in the routine of double checking that your headlights are off every time you park to avoid waking up to a dead battery.
6. Dash Cam Isn’t Hardwired To Car’s Battery
While dash cams are excellent tools for insurance purposes, they can also drain your car battery if you haven’t hardwired them to your vehicle’s ignition. A dash cam that’s plugged into your car’s power outlet will continue to draw energy from your battery even when your car is parked, slowly but surely draining it.
If your dash cam plugs into the 12V outlet instead of being professionally hardwired to your car’s electrical system, it can drain your battery after several hours. Learn more about the impact a dash cam has on your car battery in our article about it. Consider having your dash cam installed by an experienced technician who can connect it directly to your vehicle’s battery. This will allow the dash cam to run even when the car is off without putting a strain on your battery.
7. Weak Battery Condition
Most car batteries last 3-5 years, but extreme weather, vibration, and improper maintenance can shorten their lifespan. Signs like slow cranking, the need to jump start often, or lights dimming indicate your battery is wearing out. As batteries age, their ability to hold a charge decreases substantially while still allowing enough power to the car to start. But the battery discharges faster when parked, explaining the dead battery situations.
If your battery is more than 3 years old, have it tested to see if replacing it improves the frequent dead battery issue. Investing in a new battery can save you from being stranded with no-starts in the future.
How to avoid a dead battery in the future
Turn Off Your Headlights and Unplug Your Dash Cam
The first and arguably most straightforward strategy involves developing good habits regarding your vehicle’s electrical components. It may seem like an obvious tip, but forgetting to turn off your headlights or unplug your dash cam can be a swift way to an empty battery.
They can pull power from your battery even when your engine isn’t running, which, in-turn impacts the ability your car battery has to recharge itself overnight. So before you hop out of your car, make it a habit to double-check. Make sure all lights and plugged devices are switched off or unplugged when you’re done driving for the day.
Check for Loose Battery Connections
Think of your car battery as the heart of your vehicle, and the cables and connections are like the veins and arteries. If there’s a loose connection, it’s akin to a clogged artery – the life-giving power can’t reach where it’s needed. Over time, vibrations from the car or a badly fitted battery can loosen the connection.
Regular checks and tightening can nip this issue in the bud and keep your car battery from draining rapidly. By routinely checking these connections, you can ensure they stay tight and keep your battery running longer.
Maintain Your Battery
Car battery maintenance can be broken down into two categories: physical maintenance and charge maintenance. Physical maintenance involves cleaning the battery & making sure it’s securely mounted. Charge maintenance means making sure your battery’s always fully charged.
For instance, regular short drives might not provide enough time for your car’s alternator to recharge the battery fully. In such cases, using a car battery charger or maintainer can help keep your battery in prime condition.
Remove Corrosion From Battery Cables
Battery terminal corrosion is a sneaky thief, slowly reducing the performance of your car battery. Corrosive buildup is a barrier between your battery and the cables that carry power. Essentially, your battery connections become less effective overtime.
Regularly checking for and cleaning off any corrosion can keep your battery operating at its best. Corrosion related problems are easily solved if found early enough, simply clean battery cables/terminals causing the corrosion.
Look for Parasitic Battery Drains
Last is to check for parasitic battery drains, AKA electronics that consume battery power when the cars off. Common culprits are include trunk lights, glove box lights, or even faulty relays or modules. Non-hardwired dash cams fall into this category as well.
If you’ve been maintaining your battery & always turn off your headlights, but your battery still seems to drain too quickly, a parasitic drain could be your silent enemy.
FAQ
Yes, a bad alternator can be the culprit behind a drained battery when the car’s off. The alternator is responsible for charging the battery while the car is running. If it’s malfunctioning, it might not charge the battery properly, or it could even draw power from the battery when the engine isn’t running. If you notice constant battery drain without any apparent reason, it’s worth getting your alternator checked.
Here’s a basic way to check for parasitic battery drains:
Disconnect the Negative Battery Cable: Make sure the car is off, then disconnect the negative side of the battery.
Connect a Multimeter: Set your multimeter to the DC amp setting. Connect the multimeter’s negative probe to the battery’s negative terminal & the positive probe to the negative battery cable you just disconnected.
Read the Output: A normal reading is usually between 25-50 milliamps. If it’s higher, you probably have a parasitic draw.
Isolate the Culprit: Start pulling your cars fuses one by one until the reading drops back into the normal range. The fuse pulled before the biggest drop into normal range will tell you which circuit’s causing the drain.
If your car battery still doesn’t hold a charge, these are a few things that could be the issue.
Check the Alternator: Make sure the alternator is effectively charging the battery. If your alternator doesn’t work, it doesn’t matter how good your battery is; it will keep draining.
Clean Battery Terminals: Battery terminals corrode over a long enough time horizon. This leads to poor connection & reduced charge. Use a mixture of baking soda & water and start cleaning them with a brush.
Battery Test: Most auto stores will test your battery for free. You’ll be able to figure out if it has a damaged cell or is too old. Depending on the outcome, you’ll have to decide if it’s worth getting a new battery entirely or not.
Replacement: If all else fails and your battery continues to drain, then it’s time to invest in a new battery. They typically have a life span of 3-5 years, depending on usage & environmental conditions.
If you’ve tried these steps and still have issues, it’s time to consult a mechanic. No if ands or buts.
Final Words
Getting in your car & finding a dead car battery when you’re about to head to work or go somewhere important is super frustrating. Especially when it feels like your car battery keeps dying despite taking good care of it. The culprits can range from the seemingly innocent dome light or interior lights that were left on, to more technical issues stemming from the fuse box & starter motor.
As a best practice, routinely inspect both positive and negative terminals. Battery connectors riddled with corrosion will prevent the battery from charging effectively. Make sure that when you leave your car parked for extended periods, you’ve turned off all lights and accessories.
Don’t let your car sit for too long, especially in extreme temperatures, as this can significantly reduce your battery’s lifespan and the retention of the battery’s charge. A well-maintained battery not only starts your vehicle promptly but also powers all other electrical components.
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