Q: What Are the Top 5 Things That Will Change Your Car Battery?

asked by on November 30, 2015

What are the top 5 things that will drain your car battery?

Battery is dead Inspection $79.99 - $99.99 Get a Quote
Trunk Light Bulb Replacement $89.03 - $121.19 Get a Quote
Battery Replacement $229.45 - $369.99 Get a Quote

There are many reasons why a car battery will drain, but it depends on the year of your vehicle. If you are driving an older vehicle, it could be something like an aftermarket alarm system, a poorly installed aftermarket stereo system or a clock in the car staying on. It could also be as simple as a light staying on in the glove box or the trunk. There are many ways to check for a battery drain.

To check if the trunk light is staying on, put your hand on the trunk lid in the area where the bulb is. If you feel the heat from the bulb being on, unplug it or remove the bulb. Sometimes it could also be that the alternator may not be charging the battery enough and it acts as if something is draining the battery.

If you have a vehicle manufactured since 2000, then you could be having computer issues. Vehicles today are getting more and more sophisticated with technology and have more onboard computers. In the late 1990s and early 2000s, vehicles had only one computer; now a vehicle could have over 30 different modules that stay on even after you shut off your vehicle. These modules often draw a few mA (milliamps) because of something called KAM (Keep Alive Memory). Whether it’s the clock in the radio or the last known position of the memory mirrors, these tiny amounts of KAM-induced current typically will only add up to 20 or 30 mA at most. That means the vehicle can sit parked for days, or even a few weeks, without any problems of excessive battery drain that might prevent starting. As long as the vehicle is driven periodically for the alternator to recharge the battery, there is no problem.

All of these computers are supposed to go to sleep or shut down completely after a certain amount of time. Sometimes they don’t and they need to be reprogrammed to do so. If you leave accessories plugged into your cigarette lighter such as a phone charger or a GPS, these could also drain down your battery. I recommend that you unplug them when you are not in the vehicle for many reasons other than battery issues; I have seen cell phones melt down in a vehicle and cause fires inside the interior.

The easiest way to check on what is draining your battery is to use an automotive meter, connect it in series with the positive side of the battery, and have the settings on amps. There should be a reading of less than 1 amp, depending on the year of the vehicle and what make it is. Now start removing fuses one by one till the amps drop to nothing. Once they drop to nothing, then you have found the circuit that is the issue. However, you should only be doing this if you have extensive knowledge about cars and trucks. Otherwise, you should have a certified technician look at the vehicle to remedy the situation for you and replace the battery if needed.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

What others are asking

Why won't it start with a low battery and a good jump start connection?

Hi, thanks for writing in. Your battery may not have had enough cold cranking amps (CCA). The volts may be correct but if it doesn't have enough CCA, it will not start for you. Batteries that specify cold cranking...

Door ajar' light keeps dome light continually on

Hello. Normally, the cause of this problem is that the door lock switch is sticking or has failed completely. The door lock switch is located in the door jam, usually near the door latch. When the door lock switch gets...

Battery blew cap off while driving. In a few miles was running rough. Replaced it. Now it will turn over but not start

You need to have the vehicle checked to see why the battery blew the top off. It could be from an overcharge condition that may have blown fuses or burned out a computer or module. The battery acid that may...

Car keeps dying even though I jump it and the battery is less than a year old

Hello. This is not caused by the battery most likely. The alternator may not be charging the battery and, after you jump start the battery, if the alternator is not recharging it, then the battery may be able to only...

My battery is not fully charged and gradually decreasing with decrease in temperature in my 2012 Prius

Hello. Most of the time this is caused by a programming issue. I have seen these cars need to be re-programmed for issues with the batteries not fully charging in cold weather. If the vehicles computer have not been updated...

Electrical components not working in my car

The symptoms described for your Mazda indicate that you may indeed be dealing with a dead battery. As batteries age, they lose the ability to hold a charge and typically need to be replaced. Combining age with accidentally leaving a...

Car randomly died while driving, initially tried to turn over but now no power at all, scanner not piling up any codes.

Hi there. There could be an issue with the battery or the electrical system for the vehicle to stall out randomly. Check the battery for any loose connections and to see if the battery is fully charged. If there is...

Whining noise, now car is dead

From the way you describe your concern, it leads me to believe that you do have something going on with the belt drive or possibly the charging system. For your safety, the belt drive, which is driven by the crankshaft...

replaced the starter. went to connect the negative battery terminal, the starter made a whirring sound and sparked at terminal.

Electrically, there a couple scenarios that can account for this, all equally odd, but if you were not having any problems with the car's starting circuit prior to replacing the starter (i.e., just the starter motor failed) and you have...

Related articles

Symptoms of a Bad or Failing Auxiliary Battery
If you have multiple batteries in your vehicle, you may have to replace one if the vehicle won't crank, fluid is leaking, or the Battery Light is on.
10 Biggest Car-Related Headaches and What to Do About Them
You You don’t want to, but if you're a car owner it's inevitable that at some point you will experience car troubles. It's also fairly certain that the machine you rely on will cause you grief when you least expect...
Can a Car Battery Overheat in Hot Weather?
Hot weather can cause battery fluid to evaporate and make it hard to start your car. Battery overcharging decreases the lifespan of your battery.