# Over charging



## Eddy Cruze (Jan 10, 2014)

Well that Egg smell sounds like acid?


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## Patman (May 7, 2011)

First off welcome and if it is the origiinal battery from 2013, chances are it is ?"bad" I would have looked at the battery before the alternator. You may want to look into replacing the battery or at least having it tested.


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## obermd (Mar 3, 2012)

15.2v isn't overcharging. This is the voltage needed to charge the battery. Your battery is on its last legs and needs to be replaced ASAP.


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## plano-doug (Jul 1, 2015)

Eddy Cruze said:


> Well that Egg smell sounds like acid?


Yes, from the breakdown of the acid. The smell is H2S, hydrogen sulfide, which separates from the sulfuric acid, H2SO4. (And that's pretty much all I know about chemistry.)

Doug

.


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## WillL84 (Aug 5, 2019)

Doug beat me too it. The smell is battery acid. The charge volts is so high because the battery is toast and the alternator is trying to charge it back up. Get a new battery and you'll be good to go


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## RichardF (Jan 8, 2020)

Thank you all. This will be the second or third battery to get replaced I recall the dealer saying something that they replaced or had to boost it right before I bought it, that was in April of 2019 less than a year ago then I replaced a bad battery back in November of 2019 hadn’t used the car much till yesterday when my daughter was going somewhere ( it’s her car) and it was dead the key stayed locked in the ignition. I was told the battery is over charging and that’s why it died and over heating and that’s why we smell the egg. 
RF


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## WillL84 (Aug 5, 2019)

If it is indeed overcharging it would cook the battery and cause these problems as well. But 15V isn't enough to cook the battery, it'd have to be up around 18-20V typically. Also you've already replaced the alternator and are having the same problem. The voltage regulation circuitry is typically built into the alternator itself. My '17 is usually reading ~14.5V on the info display. You could have someone check the battery at the terminals with a multimeter and see exactly what's going into it. Check it with the car off and then with it running at idle and then when revved up. If it's at 15 at idle but shoots to 18 revved up to like 3000 RPM then it's a faulty voltage regulator most likely, but like I said they're usually built into the alternator itself unless these cars are doing something different


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## RichardF (Jan 8, 2020)

Thank you all. This will be the second or third battery to get replaced I recall the dealer saying something that they replaced or had to boost it right before I bought it, that was in April of 2019 less than a year ago then I replaced a bad battery back in November of 2019 hadn’t used the car much till yesterday when my daughter was going somewhere ( it’s her car) and it was dead the key stayed locked in the ignition. I was told the battery is over charging and that’s why it died and over heating and that’s why we smell the egg.


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## RichardF (Jan 8, 2020)

thanks again 
Could the battery current sensor have anything to do with it and if so is there a way to check it


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## WillL84 (Aug 5, 2019)

Honestly I don't know where the system is checking the battery voltage. It's most likely a function built into the BCM and the reading is probably taken from internal circuitry and then fed through a filter so the readings aren't jumping around like crazy lol


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## ChevyGuy (Dec 13, 2014)

WillL84 said:


> Honestly I don't know where the system is checking the battery voltage. It's most likely a function built into the BCM


Exactly. The BCM tells the alternator how much to put out. Are you having any other electrical glitches? The battery ground cable was a known issue and dealers have been told to replace it as a warranty item if certain symptoms crop up. But if that bad connection happens to be the small wire that's the BCM's voltage ground measurement, it might overcharge the battery.

I'm not sure how to check the current sensor except to use a scan tool to see what it's reading. As long as the battery cable is running though the sensor, it should be OK. Any add-ons that might also run though the sensor that might confuse it?


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## Shroomie (Jan 16, 2017)

It's 100% normal for the voltage to be at 15+volts after starting the car, this is the alternator recharging the battery after sitting and starting up. Mine does this every time. Do you have anything added to the vehicle? Attermarmet lights, fogs, or anything of that nature?


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## CapitalTruck (Jun 12, 2012)

Definitely check the current sensor.


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