6 Things That Can Drain Your Car Battery
- by Bryan Veldboom - updated on 5/9/2024
As we all know, a dead car battery can be stressful and a real headache. Finding yourself stranded isn't just inconvenient, if you find yourself in bad weather, it can be dangerous too. Fortunately, with a little TLC, you can help avoid these anxiety-inducing situations. Here are six of the most common causes of a drained battery and what you can do to help prevent it from happening.
One: Parasitic Draws
A parasitic what? Don't panic, it's not as menacing as it sounds. A parasitic draw is anything that uses energy from the battery in your car or truck. Some parasitic drains are perfectly normal to power things like interior lighting, clocks, radio settings and alarm systems. The problem occurs when your electrical system isn't functioning properly. Issues such as faulty wiring, bad fuses, malfunctioning interior lights and other electronics that fail to shut off will continue to drain your battery while the engine is off.
What You Can Do About It
How do you stop a car battery from draining when not in use? There are some things you can control, and some you can't. You can avoid parasitic drain on your battery by unplugging optional equipment such as cell phones and chargers when you park your vehicle for the night. You can also turn off every light in your vehicle and make sure that your trunk, glove box and doors are all fully closed and latched before leaving your vehicle.
If you do all of these things and still have issues with your battery in the morning, having a mechanic look at your electrical system might be a good idea.
Two: Driving habits
How you drive has a significant impact on your battery. Your battery expends an enormous amount of energy starting your engine, which is then recharged while you drive. If you take a lot of short trips in a row the alternator doesn't have enough time to recharge your battery, which will continue to be drained each time you restart your vehicle. Eventually, your battery will be drained enough to no longer have the power to crank the engine.
What You Can Do About It
Take a nice long drive, at least 30 minutes, once or twice a week. Be sure to vary your driving by taking longer, uninterrupted trips in between shorter stops. While the amount of time needed will vary from vehicle to vehicle, driving your car for about fifteen minutes after you start the engine should be sufficient to replenish the energy used to start the engine.
Three: Loose or Corroded Battery Terminals
Loose or corroded battery terminals can impair your battery's ability to transmit power, preventing your vehicle from starting. You may also experience slow cranking or notice a rapid clicking sound when attempting to start the engine.
What You Can Do About It
Clean and tighten your terminal clamps by following the steps below.
Step 1: If one is present, remove the cover from the battery box, and place it in a safe place.
Wipe loose dirt and moisture from the battery using an old rag. Move any loose wires out of the way to gain access to the battery terminals.
Step 2: Find the negative (ground) connection.
Most modern vehicles are negatively grounded -- the black (negative) wire goes from the battery to the vehicle chassis. Older vehicles may have a positive ground. If you are uncertain, consult the vehicle manufacturer's manual.
Step 3: Disconnect the battery cables.
Use an adjustable wrench, a screwdriver or a small socket wrench depending on the system used on your vehicle.
First, remove the negative cable and move the disconnected cable out of the way so it cannot accidentally fall back onto the battery terminal.
Then, using the same tools, remove the positive (red) cable from the positive terminal. Once disconnected, move it out of the way so you can safely access both battery terminals without the cables falling and touching the terminals.
Step 4: Fit a battery terminal brush over one of the terminals and rotate it to remove corrosion, debris and oxidized metal.
Continue rotating back and forth until the terminal is shining. Alternatively, you can use a combination of a wire brush and emery paper to clean the terminal until it shines. Repeat the process on the other terminal.
Step 5: Clean each of the battery cable clamps, one at a time.
Scrub each terminal clamp thoroughly using the terminal brush, wire brush or emery paper until they are both clean and shiny. Wipe them clean with an old rag and smear petroleum jelly all over the metal surfaces.
Bonus Tip
Use a terminal cleaner and terminal protection spray to aid in the removal of corrosion and help prevent new corrosion from forming on the battery terminals. All of the tools you need, including brush, cleaner and protection spray are included in the handy terminal protection kit. It's a great addition to your garage toolbox.
Step 6: Wipe any debris from the top of the battery, then reconnect in the reverse order, positive first, then negative.
Ensure that the terminal clamp sits as far down on the terminal as possible, then tighten it. Tighten it until you cannot move the clamp by hand. Do not over-tighten it as you could damage the battery terminal.
Step 7: Finally, reconnect the remaining cable, again pushing the clamp fully down on the battery terminal and tightening it until you cannot move it by hand.
Four: Extreme Weather
Use in the blistering heat of summer and extreme cold from winter driving can cause premature damage to your auto battery if left unchecked.
Heat issues:
- Evaporation: Under the hood, a car battery can reach internal temperatures of 140 degrees or higher. This causes the fluid inside it to evaporate, damaging your battery's internal structure. This is not as common with new batteries that are completely sealed, like the X2Power AGM batteries.
- Overcharging: Excessive heat can cause the voltage regulator or other charging system components to malfunction, overcharging the system and killing your battery.
- Corrosion: High heat speeds up the corrosion process and can cause your battery's terminals and internal lead plates to corrode, leading to a shorter life.
Cold issues:
- Reduced Capacity: At 32 degrees, your battery's capacity drops by 20 percent. At -22 degrees, it can drop by 50 percent. What does that mean? Less power (or no power) to crank your engine.
- Thicker Engine Oil: Cold temperatures cause engine oil to thicken, forcing your battery to work harder to power the starter and spin the flywheel to turn over the engine.
- Reduced Recharge Rate: Remember how we mentioned that your alternator recharges your battery? Well, in lower temperatures, your battery takes longer to charge, meaning you have to drive further to charge it back up or connect it to a charger when it's not being used.
- Load Increases: We tend to use more accessories during the winter to help offset the cold to keep us warm and the windshield clear. Running things like the heater, windshield wipers, defroster and seat heaters increases the load on your battery, causing it to recharge even slower.
What You Can Do About It
In summer, park in the shade as often as possible to help keep your vehicle's temperature down. In winter, park your car in the garage if you have the option. Since both heat and cold can drain your battery, you may want to use a charger when your vehicle's not in use or carry a portable jump starter in your vehicle in case your battery dies.
If you live in an area prone to extreme temperatures, you may want to invest in an AGM battery that is designed to perform in a broader range of temperatures.
Five: Faulty Alternator
Since your alternator is responsible for recharging your battery when the engine is running, it stands to reason that if your battery isn't performing properly, the alternator may be a reason. What are the signs of a bad alternator?
- Unusual electrical bugs such as dimming or overly bright lights, honking horns or other strange issues
- A consistently dead battery
- Slow or malfunctioning accessories
- Trouble starting or frequent engine stalling
- Growling or whining noises when starting the vehicle
- The smell of burning rubber or wires
- The battery warning light on the dashboard lights up
What You Can Do About It
Have your alternator tested as soon as possible to see if it's the problem. Obviously, if your alternator is down it's going to be hard driving your vehicle to a mechanic. If your mechanic is very close to you, you could possibly jump-start the car and drive over. It is more likely that you will need to tow the car to your mechanic as a car will only run for a very short time without a working alternator.
Six: Your Battery is Old
If none of the issues already mentioned are at fault, you may have an aging battery on your hands. A vehicle battery typically lasts between three and five years. If your battery is older than that, it may be time to replace it.
What You Can Do About It
Drive over to your nearest Batteries Plus location and have your battery tested for free. Not only will we test your battery, but we will also check to make sure your alternator is working as expected. Our experts can tell you if you need a replacement and help you choose the best option if you do. Batteries Plus carries all the car and truck battery brands you love, close to home! From Duracell Ultra, Optima and X2Power, we have them all.
Don't want to install it yourself? That's not a problem here. We'd be happy to install it for you while you wait. (Available on most vehicles at most of our locations. Certain restrictions apply to some makes and models. Fees may vary from location to location or the difficulty of the installation. Please contact your local store for more information.)