2010 Hyundai accent battery not charging fully?

[Rand]

I am having an odd sort of issue with this 2010 Accent.

After it sits overnight the battery shows about 12.35v.

I have charged it a few times and it seems like within a day its back down again.

Previous battery was an AAP Gold 1.5years old. I put that one in the tractor(tractor needed a battery)

and put a new AAP silver in the car.
Its doing the same exact thing.

When going down the road I see 14v.
It does have the headlights on most of the time and radio(just factory radio).

I don't drive this car except when troubleshooting or after maintenance ie tire rotation etc.

Car has 62000 miles. the battery light came on 1 time only a few months back at -5F going uphill.

It also has the org. belt and no splash guard.


AFAIK this car doesnt have any kind of smart charging system.. so I'm thinking alternator + belt while doing the alternator.

Any thoughts?.. probably wont get around to this soon been doing this since december.. battery doesn't go dead.. but doesnt charge fully.. kind of an odd problem.

Note I tested parasitic load and after 15min(iirc) its a very low draw.

Also the previous battery seems to be fine in the tractor testing around 12.65-12.7v

This is the same vehicle that has the michelin defenders that are on schedule to be below 4/32 tread @23000 miles.

 

[Quattro Pete]

Originally Posted By: Rand
I am having an odd sort of issue with this 2010 Accent.

After it sits overnight the battery shows about 12.35v.

I have charged it a few times and it seems like within a day its back down again.

My 530i is just like that. If I let the car's alternator charge the battery, after I shut down, battery voltage shows about 12.4V. And as far as I remember, it's always been like that. My last battery lasted 6 years.

 

[saltyroads]

12.45V or higher is where a healthy battery should be, have it tested.

You could have a parasitic draw somehwere or leaving stuff plugged in your cigarette lighter socket will draw power as well..

Try tightening the the alternator belt too, it could be loose and not fully charging.

 

[Rand]

Originally Posted By: saltyroads
12.45V or higher is where a healthy battery should be, have it tested.

You could have a parasitic draw somehwere or leaving stuff plugged in your cigarette lighter socket will draw power as well..

Try tightening the the alternator belt too, it could be loose and not fully charging.


Right and that's temperature dependent.
I'd expect voltage to be higher now in the 70f weather than when it was 15f out.. but its nearly the same.

There is no alternator belt. It has a serpentine belt that isn't adjustable for tension.

The only thing plugged into the cig lighter is a phone charger but its keyed to the ignition... so no power when its off. And I did mention testing for parasitic load?

Originally Posted By: Quattro Pete

My 530i is just like that. If I let the car's alternator charge the battery, after I shut down, battery voltage shows about 12.4V. And as far as I remember, it's always been like that. My last battery lasted 6 years.


I am undecided on "fixing" it. As everything seems ok for now.
just a fairly odd issue. I've been checking voltage, charging, and monitoring it for a few months now.

Changing the battery to rule out the battery was more because I needed a tractor battery asap. Getting another accent battery was only 20$ more than the cheapest one that would fit the tractor.

I did monitor the voltage for a few days with an OBDlink MX. I graphed the voltage and it seems pretty normal/what I would expect at idle and all speeds.

Not like an alternator with bad brushes where it pops down to battery voltage occasionally etc.

Also had the battery and alternator tested at AAP with a midtronics tester.. It passed.

 

[BurrWinder]

This vehicle DOES use an ecm controlled alt...
Most new vehicles do to smooth out charging and to manage for fuel economy... remember a normal 12v is considered completely "full" at 12.6 V. Newer vehicles don't overcharge like older non ecm controlled ones tend to do.
This is out of a repair manual for your specific Hyundai....


Alternator Management System
Alternator management system controls the charging voltage set point in order to improve fuel economy, manage alternator load under various operating conditions, keep the battery charged, and protect the battery from over-charging. ECM controls generating voltage by duty cycle (charging control, discharging control, normal control) based on the battery conditions and vehicle operating conditions.
The system conducts discharging control when accelerating a vehicle. Vehicle reduces an alternator load and consumes an electric power form a battery.
The system conducts charging control when decelerating a vehicle. Vehicle increases an alternator load and charges a battery.

BurrWinder

 

[4wheeldog]

What voltage does the take out battery in the tractor hold, after 12-24 hours? If it is up to snuff, then the problem clearly was not the battery. Actually.....I suspect their really isn't a problem, other than a disagreement between you and Hyundai on how much the batter should be charged.

 

[BurrWinder]

Originally Posted By: 4wheeldog
What voltage does the take out battery in the tractor hold, after 12-24 hours? If it is up to snuff, then the problem clearly was not the battery. Actually.....I suspect their really isn't a problem, other than a disagreement between you and Hyundai on how much the batter should be charged.


+1 - No problem here as you reported it... just because it isn't pushed to exactly 12.6V and held there after it is off does not mean system isn't working properly...



BurrWinder

 

[Michael_P]

Check the negative and positive battery cables with a multimeter from end to end. You should have darn near 0 ohms resistance. I have seen battery cables look pristine that were corroded where the sun don't shine that showed significant resistance (2 ohm or greater). Internally corroded battery cables can carry enough current to start a car but not enough to charge the battery sufficiently. This might not be your problem, but it definitely falls under the preliminary diagnostics procedures of the KISS method. On that Accent, you shouldn't even have to crawl under the car to do this. You might have to remove the air cleaner box and some plumbing though.

Oh........... Disconnect the cable from the battery when doing this test.

 

[Michael_P]

Even with the car off, you can have additional current draw with corroded cables.

 

[HerrStig]

Originally Posted By: Michael_P
Even with the car off, you can have additional current draw with corroded cables.
How does a circuit which does not conduct well draw MORE current?

 

[Michael_P]

Quote:
How does a circuit which does not conduct well draw MORE current?


Something as little as radio station memory which draws very little current will draw more current with corroded battery cables. There are other circuits in a modern car that require a minimal amount of voltage to remember a setting. There can be oodles of circuits on cars that "conduct" while the car is off.
Some of the very newest cars are using flash memory to keep a setting. This is why on certain cars, when you disconnect a battery and reconnect, you still have radio station presets. Even though the flash memory is usually built in to the radio itself, there is still a constant supply of voltage going to the radio.

I just knew this question was going to be asked

 

[Vikas]

Quote:
Something as little as radio station memory which draws very little current will draw more current with corroded battery cables.
Unfortunately, you are wrong. Science and ohm's law says otherwise.

 

[Michael_P]

Oops. I just understood your question. I am not really that good at explaining resistance. I am a super lousy teacher / explainer. Here goes nothing; If you think of a dimmer switch on a home lighting circuit, resistance does not go up as you dim the lights (ohms law). However, I have seen battery cables replaced and the parasitic loss stopped. I do know and old timer who used to use canned air on battery cables. He would spray the can upside down on the cable, then on a piece of plastic somewhere else on the car while the car was cold and off. If the frost on the cable would go away faster than on the other part he sprayed he would look for the loss somewhere. Sometimes that meant replacing the battery cable.

 

[barryh]

Besides smart alternator management and a quiescent current draw of something like 30-50mA there is another reason modern cars discharge their battery. They take time to go to sleep and due to a multitude of ECU's they draw several amps until they do go to sleep. Opening a door wakes them up again. Taken all together it's impossible on some modern cars that a battery can achieve and hold full charge at the end of a journey. I know that my car takes approx. 2 AH to fully charge it at the end of use after which it holds it's charge well considering the quiescent current and provided I don't wake it up. The manufacturers solution is to fit an oversized battery. My car has only a 1.6L engine but a monster 85Ah battery.

Bottom line is that even with all of the complexity of a modern car taken into account 12.35 volts is a cause for concern as it indicates 30% discharge or more depending on the battery type. I would charge it fully, establish a rested voltage and then monitor it to see what happens.

What ever you do don't open a door !

 

[HerrStig]

Originally Posted By: Vikas
Quote:
Something as little as radio station memory which draws very little current will draw more current with corroded battery cables.
Unfortunately, you are wrong. Science and ohm's law says otherwise.
+1 We don't even have to get into Kirchoffs Laws.

 

[Michael_P]

So this thread must be filled with bogus info. In particular the post from itsjusti?

 

[HerrStig]

Originally Posted By: Michael_P
Oops. I just understood your question. I am not really that good at explaining resistance. I am a super lousy teacher / explainer. Here goes nothing; If you think of a dimmer switch on a home lighting circuit, resistance does not go up as you dim the lights (ohms law). However, I have seen battery cables replaced and the parasitic loss stopped. I do know and old timer who used to use canned air on battery cables. He would spray the can upside down on the cable, then on a piece of plastic somewhere else on the car while the car was cold and off. If the frost on the cable would go away faster than on the other part he sprayed he would look for the loss somewhere. Sometimes that meant replacing the battery cable.
A dimmer for AC circuits operates on the AC waveform and can be viewed as a set of diodes with an adjustable cutoff point which passes more or less of the waveform and thus more or less power.
A resistance dimmer on a DC circuit ADDS resistance to the circuit and power IS dissipated in the dimmer.

 

[HerrStig]

Originally Posted By: Michael_P
So this thread must be filled with bogus info. In particular the post from itsjusti?
I don't see anything in that post which suggests other than a repetition of something the poster THINKS is correct.

 

[Michael_P]

Then based off of this, we can rule out the battery cable. If I were Rand, I would not even test it.

 

[Rand]

Ok so in 2009(2010 model year) they switched to smart alternator system.

I just found a press release. Apparently its smart enough to keep the battery 75% charged.

I find that odd because 2011 was the major redesign of the accent.

the 2010 gets awful fuel mileage for a small car.. my 2007 focus got 5+ mpg better.

That makes me feel somewhat better leaving it alone for now.

http://www.autoblog.com/2009/10/07/hyundai-releases-2010-accent-details-pricing-talks-up-blues-f/
Quote:

The big news for Hyundai's updated 2010 Accent is its increased fuel efficiency. The Korean automaker has managed to improve average miles per gallon by four percent in the city and three percent on the highway by means of low-friction engine internals, aero improvements, low-resistance tires and a so-called "smart" alternator system.


Previous to posting this thread..I googled for about 15min and couldn't find anything about it being a "smart alternator"