Your voltage read isn't bad enough for me personally to point at the battery charging system. Could just be a bad battery with bad cells. You would get BCM codes if you had a bad battery charging system or bad alternator.

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Your voltage read isn't bad enough for me personally to point at the battery charging system. Could just be a bad battery with bad cells. You would get BCM codes if you had a bad battery charging system or bad alternator.

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Sorry, Fabio0716, but I disagree.

Lead acid batteries should not be kept under 100% state of charge (SoC). Doing so severely reduces the life of the battery because it causes sulfication on the lead plates. A voltage of 12.2 is a 50% charge and way lower than the charging system should allow it to be.

I know the battery is fine because I hooked it up to a charger overnight and I now see a healthy 12.6v.

My questions pertained to the charging system so does anyone have the answers?

 

Car battery resting voltage is 11 to 11.5 volts which it would have been out of the car. 12.2 volts is not 50% charged. It is a 12 volt battery after all...

Sounds like you may have a bad battery. Did you check the amperage of the battery?

 

11v to 11.5v is a completely discharged battery. A fully charged 12v lead acid battery should read 12.6v - 12.7v.

See these references:
https://www.electronicproducts.com/Power_Products/Batteries_and_Fuel_Cells/Lead-acid_batteries_The_growing_need_for_monitoring_state-of-charge_and_health.aspx

and

Measuring State-of-charge - Battery University

 

Most likely a bad cell in the battery.
The interior of one cell may have broken, or cracked, or disintegrated..
I would say it is a bad battery and you need a new one.

Even though the battery is not that old, shit happens.
Your battery may have a partial prorated warranty?
Not sure if it is one year or two or three...

 

Any Generator/BMS (charging system) fault illuminates the red battery warning indicator on the IPC. In severe cases the BCM will load shed AND get the warning message on the panel.

So to answer your questions. "My questions are how does the battery management system decide on the amount of charge to give a battery? What if it underestimates? Can I simply reset this system while still using an old battery and it will readjust itself?"

1. It uses battery time in service , temperature, current, and voltage to determine battery" age" and from there the computer decides what the ideal charging voltage and battery voltage should be to keep all normal functions.

2. This could be a possibility but is highly unlikely unless you have a non BCM controlled electrical draw on the vehicle like any aftermarket stereo system and such that could be drawing current undetected.

3. NO, The BMS calibrates itself every 4-6 hours while the car is "asleep" (left alone overnight or long period of time). The self calibration occurs automatically and will be interrupted if there is any non BCM draw on the battery. This will cause the battery to be incorrectly charged and the BMS and BCM will read battery voltage incorrectly.
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Any Generator/BMS (charging system) fault illuminates the red battery warning indicator on the IPC. In severe cases the BCM will load shed AND get the warning message on the panel.

So to answer your questions. "My questions are how does the battery management system decide on the amount of charge to give a battery? What if it underestimates? Can I simply reset this system while still using an old battery and it will readjust itself?"

1. It uses battery time in service , temperature, current, and voltage to determine battery" age" and from there the computer decides what the ideal charging voltage and battery voltage should be to keep all normal functions.

2. This could be a possibility but is highly unlikely unless you have a non BCM controlled electrical draw on the vehicle like any aftermarket stereo system and such that could be drawing current undetected.

3. NO, The BMS calibrates itself every 4-6 hours while the car is "asleep" (left alone overnight or long period of time). The self calibration occurs automatically and will be interrupted if there is any non BCM draw on the battery. This will cause the battery to be incorrectly charged and the BMS and BCM will read battery voltage incorrectly.
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Thank you for the information, Fabio0716. I'll have to check the current draw with the car off to see if anything is draining the battery. Is there an amount of current draw from the car's systems that would be expected when the car is off?

 

What is the age of the battery?

What is the voltage reading at the battery when the car is running?

What is the voltage reading when trying to start the car?

Have you taken the battery to an auto parts store to have it load tested?

 

Age of battery: 3-4 years, perhaps. It's the original battery in my 2014.
Voltage when running: 14.2-14.6 (It varies)
Voltage when starting: I tried this a couple times. Saw 11.6v and 9.6v.
Had it load tested today: Passed for 500CCA