Top 5 Things That Will Drain Your Battery

Car owners typically fall into one of two buckets: those that have experienced a dead car battery at the worst possible moment, and those that will. (Some of us can claim to have had this experience more than once, unfortunately.)

One surefire way to reduce your chance of getting stranded in your car with a dead battery is to know the top 5 things that cause your battery to drain (and learn how you might prevent them).

1. The battery is old

Ok, so you can’t prevent your battery from aging, but you can perform regular maintenance on your battery which will do two things.

  1. First, regular maintenance helps keep your battery up and running longer.
  2. Secondly, regular maintenance will give you a heads up that your battery is losing the fight. This gives you time to have a new battery on hand in the event that this one bites the dust.

Outside of testing your battery to see if it’s holding a full charge, you can keep an eye out for how it’s behaving. Meaning, if the battery is not starting consistently or you’ve had it for more than four years, it’s time to start looking for a new one.

2. You made a manual mistake

It’s perfectly normal to forget to turn off the headlights (especially on a rental car) or completely shut the trunk, or leave an interior light on. These things happen to the best of us.

Unfortunately, declaring to the universe, “I’m only human” will not change the fact that your battery is now dead. All because you were in such a hurry that you forgot to check that all the lights were off. Good news is that a quick jump and a drive in the car to recharge is all it will take to get you back on the road again.

If you happen to make a habit of this kind of behavior, you’ll want to make sure you always have a set of jumper cables in the car. You may also want to look into a portable battery charger.

3. The charging system isn’t working properly

If you have ever been driving down the road and still end up stranded with a dead battery, you can safely assume that your charging system isn’t doing its job.

Typically when you are driving, components such as the radio and lights get their power directly from the alternator while it charges your battery. When the charging system is down, not only is it not charging your battery as you drive, but your components are relying on whatever charge the battery has left, causing it to drain even faster.

At this point, no amount of jumpstarts or new batteries will save you. The best bet is to have your mechanic take and look and see exactly what the issue is.

4. There’s a defective diode

A defective diode is one reason your charging system may be letting you down. When one alternator diode goes, typically the others will be able to keep you running, but not for long.

The more current the working diodes have to carry can create a drain on the battery by pulling a charge even if the car is turned off. Your mechanic can tell you if one or more of the diodes have gone bad.

Replacing the diodes as needed is a lot more cost effective than to just keep pushing it and having to rebuild the alternator later on down the road. If you are so mechanically inclined, you can typically replace the diodes yourself.

Most automotive stores have alternator kits that allow you to replace the bearings, diodes, and brushes all at the same time. This is a great way to keep your alternator working so that your battery doesn’t pay the price.

5. Parasitic drain (by way of an electrical problem)

A parasitic drain occurs when the car is turned off but certain components continue to draw power. Some instances of a parasitic drain is normal. Otherwise, how would your security system remain armed or the clock be able to keep the right time?

When parasitic drain becomes a problem, it’s typically because of an electrical issue that’s causing one (or more) of the car’s components to continuously draw power even when the car is off.

One of the most noticeable symptoms of an electrical problem can be seen before the battery dies completely. If the headlights or brake lights are noticeably dim, you may want to see your mechanic. Another sign is the appearance of loose wires.

Getting these symptoms checked out before your battery completely loses its charge could keep you from being stranded with a dead battery.