Gents.....Have an old but trusty 2007 Sonata with over 200K miles. Can't kill the thing. Anyway, about 5K miles ago the alternator pooped out so I purchased a rebuilt one for 100 bucks . I also purchased the top tier Pep Boys battery (Champion) since the old one was 6 years old. This was a year ago. About 6 months later the car wouldn't start because the battery was dead. I had Pep Boys check the battery and sure enough it was bad so they gave me a new one. Last week I went to start the car and the same thing....battery dead. Pep Boys again checked the battery but it showed good so I checked the alternator voltage at idle which showed 13.5 volts. Is13.5 volts at idle enough to charge the battery? Does this year Sonata's computer control the voltage or is it like my old Camaro which has a voltage regulator in the alternator. One other piece of info is that I don't drive much any more and the car will sit for several days at a tine. However, my live at home college boy doesn't drive his car at all (2005 Malibu) so I start it every couple of weeks without a problem. I remember my old Camaro showing a tad over 14 volts at idle so I suspect something is going on with my new old rebuilt Sonata alternator. What do you think? Thanks my friends.

 

What we need to know is,
Is the alternator capable of putting out more current if necessary ? If not ,the alt is defective.
If it is, then could there be some reason for the output is being limited ?

What you might try,
With the headlights on , hi beam, engine RPM over 1500, , what kind of voltage are you reading at the battery now? If it is still the same, the alt is capable of maintaining the battery charged.. If not , there could be a poor connection where the voltage sensing of the alt says the battery doesn't need more charging. . Now you need to start some voltage drop testing to locate the cause.

 

Makes all the sense in the world to put a load on the battery, headlights, AC etc., then note the voltage which is something I should have thought of. I'm tied up right now though.....third beer and the misses is yelling at me for drinking. I'll address this after I put the misses over my knees to spank her then forget what I'm mad at her about!. This forum is great! Thanks

 

While my boy was inside the auto turning on lights etc. and revving the engine, I observed the voltage. 14.1 volts at idle and higher. Curiously, the voltage did not increase what so ever even at higher rpm. I do think the computer is controlling the voltage but I'm not 100% sure. Anyway, the fact that voltage is adequate and the battery lasts 6 months before failing makes me believe this is a battery problem. However, with PepBoys stating the battery is good leaves me little choice but to buy another battery from a different store.. The new battery won't be a Champion. Believe it or not I've had great luck with Walmart batteries! Thanks for your help.

 

I have so far, never had any problems from Walmart/Everstart batteries.

I hope you are sitting down when you get the price of a new battery these days. The price went through the roof.

There may be something going on with Pep Boys stores, not sure if they are planning to stay in business.

 

Thanks Hanky for giving me confidence to purchase a new Walmart battery.....Always thought though Pep Boys and especially Champion batteries would be the ticket for another 6 year battery! However, I'm still going to write Pep Boys just to see how they respond. If you want I can post the Pep Boys response when or if I get one. Thanks again

 

Thank you for the update.
Anything we can do to help folks save some $$$ is always welcome.

 

I wrote PepBoys a respectful but to the point letter attaching receipts and a picture of my voltmeter showing a charge of over 14 volts. I asked for a battery replacement or a refund to purchase a different battery from them. PepBoys has a stand alone customer service department so I'm anticipating a positive response from them.....hopefully, in my old age, I'm not dreaming!

 

Got a reply from PepBoys.....that was fast. The one line response was to take my auto to the store where I purchased the battery so they can resolve my issue. Got a feeling I will be purchasing a new battery and alternator for top dollar.

 

We as much as possible try to be reasonable when it comes to complaints regarding parts or service..
So far that seems to be happening.
From the results you provided, I do not believe there is an alternator problem.

If they are willing to replace the battery , I would consider having it done UNDER WARRANTY..
Then see what happens. If all is well, everybody should be satisfied.

A little side note, do you know if all the connections have been checked for cleanliness and tight?

Always a good move to be sure all the tees and I s have been crossed and dotted.