Posted by & filed under Battery Maintenance, Car Maintenance.

Question:
My battery keeps going dead. I had it tested and it is fine – what could be the problem?

Mira Mesa Automotive Answer:
Well, your problem could be caused by several things. Let’s start with a likely suspect: your alternator. The alternator is like a little electrical generator. It is spun by the serpentine belt on your engine and makes electricity. This electricity is used to power the critical electrical systems required to run your auto. It also powers all of your electronic accessories like your stereo, navigation, heated seats, and air fans, as well as charging all the electronics you have plugged in.

After the alternator has performed all that, any electricity that’s left over is used to charge your battery. You can see where we’re going: if the battery isn’t getting enough electricity to stay charged the trouble may have something to do with the alternator.

Now it could be that the alternator is bad – they do wear out over time. There are a number of failure points within the alternator, but in practice, it is less expensive to simply replace the alternator than to take it apart and repair it.

At Mira Mesa Automotive in San Diego, we can test your alternator to see if it needs to be replaced. We find that generally the alternator tests out as being OK – but for some other reason it’s not putting out enough electricity to keep the battery charged. Remember we said that the serpentine belt drives the alternator? Well the problem can often lie with the serpentine belt system.

The serpentine belt transfers power from the engine to the alternator. When the belt wears away to a certain point, it is no longer able to provide enough grip and the belt can slip on the alternator pulley so that it is not spinning speedy enough to generate all the electricity that your auto needs.

A possible related trouble for San Diego motorists is a worn serpentine belt tensioner pulley. This pulley provides tension on the serpentine belt so that it is tight enough to spin the alternator and other accessories. When the belt is too loose, it can slip on the alternator pulley and, once again, not enough electricity is made.

So, when you battery is going dead – test it. If the battery is still good – test the alternator. If the alternator is still good – inspect the serpentine belt and belt tensioner. Chances are good that your service center or the team of friendly techs at Mira Mesa Automotive will get to the root of your trouble.