Posts Tagged ‘alternator’


Why Do My Batteries Keep Dying?


I’ve had my car for 2 years and have needed to replace the battery 4 times.  I’m pretty sure I’m not leaving anything on overnight or anything.  What could be the problem?

David R., CA


There are two things which could be happening.  One is that there could be a drain on the battery you don’t know about.  To check, leave the car as you normally would overnight.  Disconnect the negative battery terminal, and use a multimeter between the cable and the battery to check for amperage.  If you measure anything over about .05 A, you’ve got something running that is draining the battery.

If this test doesn’t show anything, your alternator/regulator is likely acting funky.

- Ken the Car Guy


Is A/C Harder On My Engine?


I’ve heard from several people that running the air conditioning is bad for the engine.  Is this true?  Why would it hurt the engine?

-Jeff D., NV


This bit of misinformation has been around for years.  In reality, running the A/C shouldn’t have any effect on your engine.  Your engine has to run anyway while you’re driving, it might as well use some of the power it creates to make your air conditioning work.

Cars are definitely built with A/C in mind, especially nowadays.  If cars were really damaged by running the A/C, there’d be a lot more cars in the junkyard.

- Ken the Car Guy


Did I Just Kill My Battery?


I was replacing my old alternator and forgot to disconnect the battery.  While moving things around, I accidentally crossed the positive and negative wires on the alternator, which made a big spark and now nothing seems to work.  Is my battery toast?

-Michael D., IN


Don’t worry, you’re not the first to make this mistake.  I remember a similar thing happening to me many years ago.  I too was messing with the alternator and after a frightening spark, the wires were dead.  In my case, I had only blown a fuse.

Check the user manual for your car to figure out where your fuse box is, and look for a large amperage fuse, somewhere around 120 A.  If this fuse is busted, you’re in luck and there is probably no damage.  If the fuse is in good shape, you might have melted a wire or connection between the alternator and the battery.  Use a multimeter to test all of the wires running to the battery to see where the damage is.  While you’re at it, use the multimeter to test the battery to make sure it’s still pumping out 12 Volts.

- Ken the Car Guy


Why Does My Battery Keep Dying?

I wanted to know if I need a new battery or could there be another problem?

I took the battery out of my car and took it to a auto parts store. They placed it on a machine and said it was still good but still needed to be charged.

So I went back and got the battery and placed in back in my car. It ran for a day or so and when I went to get in my car and crank it up it would not start again.

Why would this happen? Thanks.

- Peter D., MO

Dear Peter, the problem is that the alternator is not charging the battery.

It may be that there is a problem in the alternator prohibiting generation of enough electricity or not allowing enough electricity to pass through to the battery to charge it while the engine operates.

Or, it can be that the voltage regulating circuitry that controls when and how much electricity is sent to the battery while the engine is running.

Hope this helps.

- Ken the Car Guy


Why Do My Headlights Flicker On and Off?

Dear Ken, I recently installed a new alternator on the used car I found on Cars for a Grand. The cars great, but since I put it in I’ve had nothing but flickering headlights.

Even the idle goes up and down whether the lights are on or off.

Can this be loose wiring or could it be a bad voltage regulator?

- Gus M., IL

Dear Gus, first check the belt to be certain it is tight enough and meets specification. If it’s slipping, it could cause the alternator’s speed to vary, thereby changing its amperage output. That could cause lights to flicker. A loose belt could impact idle speed on lower-horsepowered engines.

Also, a loose connection could also cause headlight flickering. Check for clean, solid electrical ground at the alternator’s mounting points.

Last, a failing voltage regulator could be the problem.

The voltage regulator might have been damaged by — or caused damage to — the old alternator, necessitating its replacement.

Hope this helps.

- Ken the Car Guy


Why Does Car Need to Be Jump-Started with New Battery?

Dear Ken, the used Ford pickup I just bought from Cars for a Grand will not start unless I jump start it even with a new battery in it.

Any idea of what could be wrong?

- Gus L., MO

Dear Gus, first check the battery cables.

Sometimes these connections can becomecorroded and stop transmitting electric current.

Also, check the alternator belt to see if its worn. If not, then it could be the alternator. The wiring on it may be wrong,
but most likely the alternator gave out.

Make certain that the charge that is being produced by the alternator is actually being fed into the battery.

Hope this helps.

- Ken the Car Guy