5 Reasons Your Car Battery Keeps Dying: Capitol Subaru Auto Care

January 27, 2020

It's happened to just about every motorist at one time or another: you go to turn on your car and nothing happens when you turn the key. Naturally, a dead battery can usually be blamed for this problem, but what caused the battery to die in the first place? Today's modern car batteries are designed to discharge and charge back up again thousands of times over its life. A battery that suddenly dies and keeps dying after multiple charges and jump starts might need to be replaced. If not, there could be a variety of other issues with the system that keeps your battery charged as you drive. Here are five of the most common reasons your Subaru vehicle's battery is repeatedly dying.

5. Parasitic Drain

Now, we probably don't have to tell you that your battery may drain overnight if you leave an accessory on, such as interior dome lights. But even if you turn everything off, your battery may drain overnight due to a malfunction in the electrical system. This is called parasitic drain. A wiring short, a malfunctioning electronic component or an aftermarket accessory that was incorrectly installed could result in parasitic drain. Parasitic drain will continue to draw current from the battery, even as the car is parked, until the battery is drained and you'll need a jump-start to get going the next morning.

4. Short, Intermittent Drives

The car battery is just one part of your vehicle's charging system. As you drive, a component called the alternator turns the mechanical energy generated by the engine into electrical energy that recharges your battery.

Paradoxically, this can mean that the battery on your car might die if you aren't driving long enough for the alternator to do its job. If you've got a car that's only used for the odd trip to the corner store down the road, and the battery continues to die, consider taking the long way home once in a while. The extra time will allow the alternator to recharge the battery longer, so you'll have more charge left for next time you attempt to start the vehicle.

3. Battery Corrosion

A build-up of corrosion on the terminals of your car's battery can interrupt the battery connection to the rest of the system, keeping your car from starting up. The chemicals that store electricity inside the battery also release small amounts of reactive gasses. These gasses can react with the metal on the battery terminals themselves as well as the battery cables. The result is a blue-ish, green-ish or grey-ish, powdery substance that builds up on the battery terminals. Sometimes, getting your battery working like new again is as easy as removing this corrosion with a wire brush.

2. Faulty Alternator

If the connection between the battery and the rest of your vehicle is in good shape, but the battery still isn't holding a charge, the alternator may not be working. At Capitol Subaru, we have special tools that can test your alternator and quickly determine if you need a new one.

The alternator can go bad internally due to wear and tear, or due to bad bearings, and need to be replaced. Or, the alternator might stop working due to a bad accessory belt or damaged pulley, which could be repaired, leaving the original alternator in-tact.

1. Battery Needs To Be Replaced

Finally, the last potential reason might be the most obvious: the battery is simply too old to hold a charge anymore.

On average, most car batteries will last about 5 years, but your mileage quite literally may vary. Cars that spend their lives in extreme weather areas with very hot or very cold temperatures will have to replace their batteries much more frequently than in places with mild, dry climates. If you're not sure if your battery needs to be replaced, head to the Capitol Subaru service center! We can quickly perform a battery health test to determine if your battery has plenty of life left in it, or if a new battery is in order.