Reasons Your Car Battery Keeps Dying - Service Research at Mike Shaw Subaru

If your car's battery drains entirely just once, it's most likely that a dome light or other accessory was accidentally left on -- but what if your car's battery keeps dying, even after you've meticulously checked for things to turn off before you exit the vehicle? That means there could be a problem in the charging system. Or, it could mean your battery is simply aging less-than-gracefully, and might need to be replaced. Below, we'll tell you the five things that most commonly cause your car battery to keep dying.

A man braves the snowy weather to jump start his car. Get your battery tested so you don't wind up jumping your car in the cold

5. Bad Alternator

As you drive along, an accessory called the alternator converts power generated by the engine into useful electricity that keeps your car's battery charged. That way, there's always enough juice in your battery to start the car, run the stereo and keep things like power locks and seat position memory working -- even when the engine is off.

If the alternator stops working, the battery will eventually drain completely. And then you'll be stuck. You might be able to get a jump-start and get moving again, but the battery will quickly die once again if the alternator can't recharge it. To fix it, a technician will need to find out why the alternator isn't working and perhaps replace it with a new or remanufactured unit.

A technician uses a tool called a voltmeter to test the health of this vehicle's battery

4. Parasitic Draw

But what if your car's alternator is working correctly? There could be a variety of other things at play.

If there's a wiring short, a ground fault or just a malfunctioning electrical accessory, your vehicle could be suffering from parasitic draw or parasitic drain. As your car sits, the malfunctioning component draws excess current from your car's battery. When the engine and all accessories are off, the car should only drain a very small amount of electricity from the battery. If the battery is draining too quickly, you'll want a technician to help find the problem.

3. Corroded Battery Terminals

Over time, corrosion can build up on your car's battery terminals. Fortunately, it can easily be cleaned with a wire brush in most cases. But, if enough corrosion builds up, it can even interrupt your car's battery connection and prevent the battery from charging properly. It's a good idea to peer under the hood and take a look at your car's battery terminals from time to time. If they're starting to cake up with a whitish, yellowish or blueish, powdery looking substance, grab a brush or swing by our service center to have your battery cleaned, and see if that fixes your undercharging problem.

Some whitish powdery corrosion has begun to build up on this car's battery terminals

2. Extreme Temperatures

If your car's battery is on the old side, but still trucking along without problems, you may find it starts to act up when the weather gets extreme. In particular, you might find that a day or two of particularly cold temperatures, like we see during winter in the Denver area, may be enough to do your battery in. That's because, the colder the temperature is, the less the output of the battery. What's more, the engine's starter has to work harder and draw more power when it's very cold out. If your car's battery stops working in a cold snap, you're likely to just need a new battery.

1. Battery Is Simply Too Old

A car battery's typical lifespan is roughly five years. In some cases, you might find you can get six or seven or more if your car is garage-kept, well-maintained, gently-driven and doesn't encounter too many extreme temperatures.

That means, if you experience problems with your car's battery, and it's four or five or more years old, it's probably just too old to hold a strong charge. You'll want to have a new battery installed.

To get the ideal battery for your car, visit our service center at Mike Shaw Subaru! We use only parts, accessories, chemicals and batteries recommended for use on your car by the Subaru factory. Don't forget to browse our parts coupons to see if you can save even more on a new battery for your car this month!

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  1. Mike Shaw Subaru

    1650 W 104th Avenue
    Thornton, CO 80234

    • Sales: (888) 472-4482

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Mike Shaw Subaru

1650 W 104th Avenue
Directions Thornton, CO 80234

  • Sales: 720-724-9280
  • Service: 303-729-2683
  • Parts: 720-728-0862