2014 Hyundai Santa Fe, alternator probs or not?

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Here's the story: over the last six months or so my wife's daily driver Santa Fe (2.0T) with original OEM battery (4+ years old) would start fine, get her to work and then at quitting time she'd find a dead battery, requiring a boost to get going again. She admitted leaving interior lights on a couple times which I figured caused the dead battery. This has happened three times total, the last time being last week. Given the age of the battery and the number of total discharges it's had, I decided to replace the battery with a Duracell 124R which is a perfect replacement for the OEM unit and it has slightly better performance numbers than the original. I should have tested the charging system before replacing the battery, but I didn't.

I've since done some tests with my multi-meter on a few occasion just to get a feel for what "normal" is for the charging system. The numbers I've seen (with the new battery) is as follows (all measurements across the battery):

After sitting over night, engine OFF: 12.65V
After sitting over night, engine ON: 14.44V (a few seconds after start-up, at low idle)
Fast idle (2000 RPMs a few minutes after start): 14.42V

Here's the weird instance that I have a question about: I checked the voltage after a recent short trip around town (engine ON at idle AND at 2000 RPMs) and the voltage read 12.67V, which I found odd. There were NO malfunction lights showing on the panel. I expected to see a charging voltage above 14V. After the next start-up, the numbers were back to the above readings. My question is: would the voltage regulator ever normally cycle the alternator off completely, as it would appear happened by this voltage reading? I've since had Autozone check the charging system with their diagnostic device and they said everything passed.

Do I have an intermittent charging system malfunction that's randomly killing the battery, or is this normal operation for a late model Hyundai?
--Rob
 
It is possible that the alternator or the regulator is not working properly. Check the connections at the battery posts and back of the alternator. Running reading 12.67 volts not good enough.
 
No this vehicle is equipped with a smart charging system and this is perfectly normal. As long as the battery stays above 12.3 volts and doesn't charge past 12.7 volts it's perfectly normal to see the alternator kick out and run solely on battery alone. They do this for fuel economy and to extend the life of the charging system and battery.

I had a similar vehicle with the same setup.

Good Resource explaining it: https://www.redarc.com.au/alternator-vs-fixed-alternator
 
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You might have been able to save the old battery by putting it on a charger and letting it fully charge up. Half dead batteries don't last as long as those that are fully charged. Seems like most manufacturers are playing games with their charging algorithm so that the battery doesn't get fully charged and it gets slightly better gas mileage at the expense of battery life.
 
We have a 2015 Chevy Sonic , purchased in late June of 2015 . We had to replace it early part of this year .

I figure , around here 4 years on a factory / OEM battery is about normal . Ours did not make that .
 
Originally Posted by WyrTwister
We have a 2015 Chevy Sonic , purchased in late June of 2015 . We had to replace it early part of this year .

I figure , around here 4 years on a factory / OEM battery is about normal . Ours did not make that .


Well you have the Texas heat to bake your battery. They should last longer in colder climates like Pennsylvania.
 
I'd agree that the operation/readings are likely normal...I have a five and a half year old battery in my Hyundai with a smart alternator system and its longevity is starting to scare me.
 
Originally Posted by Vuflanovsky
I'd agree that the operation/readings are likely normal...I have a five and a half year old battery in my Hyundai with a smart alternator system and its longevity is starting to scare me.


I got 8 years out of mine in the Santa Fe even though it wasn't a smart system.
 
Give the battery a charge. If not, you might start seeing crank positioning sensor faults, cause by low voltage.
 
"Smart Charging" systems: Great for EPA tests, bad for battery life. Constantly dropping SoC for economy purposes is abuse for flooded lead acid starting batteries.
 
Originally Posted by PeterPolyol
"Smart Charging" systems: Great for EPA tests, bad for battery life. Constantly dropping SoC for economy purposes is abuse for flooded lead acid starting batteries.


When I contacted Toyota about it they said it extends battery life so long as it doesn't fall below 12.3 volts. I know it's a biased source but just FWIW.
 
Originally Posted by PeterPolyol
"Smart Charging" systems: Great for EPA tests, bad for battery life. Constantly dropping SoC for economy purposes is abuse for flooded lead acid starting batteries.


I think it might be a case by case scenario with that idea because, for example, some will experience spikes due to regenerative braking with their vehicle and some won't...some will have some form of smart alternator regulator that monitors things like the absorption voltage and the battery temperature. If it maintains 80% SOC through this regulation, I'd think the battery would last longer.
 
Thanks for the comments guys! I thought I'd seen something about an ECU-controlled charging system on a Hyundai forum, but I couldn't find it on a Google search. Based on your comments, it seems that the charging system is performing in spec, the battery was on it's way out and replacing it (before winter) was the way to go. It had been completely discharged at least three times over the last year, and my wife was getting frustrated with having to use the jumper-pack in a dark parking garage--replacing the battery was a no-brainer. Thanks again for the education--this forum is great! --Rob
 
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[/quote] I got 8 years out of mine in the Santa Fe even though it wasn't a smart system. [/quote]

I previously had a 2008 Santa Fe (3.3L V6) for six years and traded it in with the original battery for the 2014 model--go figure!
 
Originally Posted by Robster
[/quote] I got 8 years out of mine in the Santa Fe even though it wasn't a smart system.


I previously had a 2008 Santa Fe (3.3L V6) for six years and traded it in with the original battery for the 2014 model--go figure![/quote]

Just luck of the draw sometimes.
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I'm a big fan of stress testing the battery every year around this time to make sure it's good for the winter just in case.
 
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