5 Causes of a Car Battery Drain and Replacement Cost


The main function of a car battery is to help start the engine. After that, the alternator takes over by converting mechanical energy into electrical energy for all the vehicle’s electrical components. But the car battery needs to be functional or else this entire process will not begin. A car battery should last for a good 2 to 5 years, depending on how much you drive your vehicle. However, if you notice that your car battery is losing too much power or going dead a lot sooner than it should be, then something is causing the car battery to be drained of its power too quickly.

The Top 5 Causes of a Car Battery Drain

There are lots of reasons for a car battery’s power to be drained. Below are the top 5 causes of this which could help you figure out why your car battery is going dead prematurely.

  1. Bad Alternator – When people get electrical problems, they often don’t know whether it’s the car battery or the alternator that’s gone bad. If it’s the alternator, this can actually cause the battery to lose power and go bad soon afterward. If the alternator is failing to deliver power to the vehicle’s electrical components, then the vehicle will depend on the battery to supply this power instead. Since car batteries don’t have enough power to satisfy all these components, the battery’s power will be drained quickly.
  2. Worn Out Battery – Alternators are responsible for recharging the car battery with power. But if the battery is old or too worn out, then it won’t be able to get recharged properly and hold power like it used to. This means you’ll constantly have problems trying to start your vehicle.
  3. Faulty Charging System – It is possible to have a good battery and alternator, but to still have a problem when it comes to charging the battery. This problem lies within the charging system and it can cause power to be drained from your battery as the vehicle is being driven. To make matters worse, the battery power will drain even more if you’re using things like headlights, air conditioner, or radio.
  4. Left Something On – A lot of newer vehicles will automatically shut off its electrical components when you turn off the engine, get out of the vehicle, and then shut the door. However, if the door does not completely close or you didn’t completely close the trunk, then it could still leave the headlights or cabin lights on all night long. This will drain the battery and then you’ll find that your car does not start up in the morning. Hopefully, you have alerts on your vehicle that will prevent you from doing this.
  5. Electrical Problem – If you turn your engine off and the vehicle’s electrical components continue to operate, this is called a parasitic drain. Sometimes this can be normal when it’s just powering the security system and clock of your vehicle after it’s turned off. But if it’s powering other things like dashboard computer screens or headlights after the car is turned off, then you have some kind of electrical problem that is draining your battery.

The Average Replacement Cost

The good news is that car batteries do not cost that much to replace. You can get a new car battery from between $100 and $150 on average. It is also one of the few components of a vehicle that is easy enough for anyone to replace. That way, you don’t need to spend an extra $45 on labor costs just to have someone take out your old battery and put in a new one. It shouldn’t take you more than 15 minutes to do this yourself.


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