If you own a car, you have most likely experienced a dead battery in your car ownership history. There are many different reasons why batteries die. It can occur as a one-off from a user-error, such as when headlights are left on, which may not be too inconvenient if you have someone to help right away. However, if you find your car battery is dying repeatedly, then there’s a good chance that it’s due to an underlying problem that needs to be dealt with before more complications arise.
The 4 Most Common Causes of a Dead Car Battery
If we were to write a list of every single problem that could cause a dead battery, it would be endless. Thankfully most of the causes can be grouped into two basic categories: electrical systems issues and simple user errors.
Most battery issues can be solved at home while some will require a trip to your local mechanic. Below, we have listed some of the most common causes of a dead battery.
Headlights or dome lights left on
Forgetting to shut off your headlights, dome lights, and other electrical accessories is one of the most common reasons for a battery to die. It’s true that car batteries are designed to keep these parts powered, but not for a very long time.
If you forget to shut these parts off when parked for more than a couple hours or less with a weaker battery, chances are very high that you will end up with a dead battery. If you find your battery is dying over and over again, it may be worth a good inspection of any lights (inside or out) or any other accessories that could be drawing from the battery after you’ve parked.
Battery in weak or poor condition
A battery that is poorly maintained or otherwise weakened may not be able to hold a charge. If a battery is weak enough, then even the smallest drain, like a radio, can kill it.
Keeping a battery properly maintained is fairly simple. One of the first things you want to check is whether or not the battery is sealed. If it is not sealed, then you will need to make sure each cell is filled to the proper level with liquid electrolyte.
You can determine electrolyte level simply by looking inside the cells. If you find the electrolyte level has fallen below the lead plates, then you will have an issue. If you can’t tell just by looking, you could also purchase a tool called a hydrometer. The function of a hydrometer is to determine the specific gravity of the electrolytes in each cell. If you find any cells to be very low even after charging, then your best course is to replace the battery altogether. For any issues or problems, come by Bavarium Autoworks for help.
Corroded or loose battery connections
Corroded or loose connections can also cause your battery to not function. Sometimes you can spot corrosion just by looking at the terminals, cables, and connectors. If you see any white, blue, or green “blooms”, this means your battery is corroded. You might be able to remove the corrosion yourself, using a stiff-bristled brush and a mixture of baking soda and water. Another great corrosive remover is Coca-Cola. Whichever you use, be careful not to get any baking soda inside the battery cells.
Another common cause for a dead battery is loose cables or connectors. Connections should be tight. If you notice the connections are loose, this is a good sign that this is the issue. Also, look closely at the ground and power cables that lead to the frame, starter, and junction block. If any of these are loose or corroded, then this is probably the problem.
Other parasitic drains in the electrical system
If you can’t find any loose or corroded attachments and 
you’ve ruled out headlights or dome lights, then your battery may be dying due to another component draining its power.
Some causes of parasitic drains include a bad amplifier or other radio attachments or a radio itself. The best way to check for a power drain is to disconnect the battery cable and then check the current flow. A multimeter is a good tool for this test, but you’ll want to use the highest possible amperage setting to avoid blowing a fuse in your meter.
If you are not able to detect the cause of your dying or dead battery, you may want to turn to our professional mechanics for advice. Bavarium Autoworks performs superb work on Audis. We are conveniently located to serve the Cupertino, Palo Alto, San Jose, Santa Clara, Saratoga, and Mountain View areas of CA. Call us or stop by today!