# Weird Battery Issue



## oreo382 (Sep 17, 2014)

I went out to start the car yesterday afternoon,it was -23 Celsius.Turned the ign. on and waited for the glow plug light to go out then cranked the car.It turned over really slowly for about 3 seconds then stopped.Tried a few more times and nothing but a few clicks then nothing at all.I had replaced the battery a year ago with a big(900cca) lead acid.Phoned the store where I bought the batt. and they said to bring it down to get checked out.They suggested to put the batt. on a charger(which I have) and bring the car down.I have a 6/2 amp charger so I put it on the 6 amp setting,the needle went to 6 amps immediately.I left it charge for about an hour and it started right up.Took the car to the store (15 minute drive).The tech put a load test on it twice,it held 9.6 volts for about 10 seconds each time before he stopped the test.After each test the terminal voltage recovered to 12.4 volts (battery was probably about -20 celsius).He said it was good.The tester he used didn't display amp draw but I saw him cranking the rheostat all the way(i'm assuming increasing draw).I asked him what kind of current draw and he said about 1/2 the cca.he said to charge it overnight when i got home and to keep an eye on it,bring it back if I have any more trouble.My question is how can a dead battery come back to life in an hour according to the test? First that comes to mind is the load tester draw is not very much,however the car started up right after and I drove to the grocery store,shut it down and came back and it started right back up no problem.I have it on 2 amp charge overnight,will see what happens in the next few days.I drive the car daily during the week,total running time about 1 hour per day.Weekends less.Any thoughts?


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## MRO1791 (Sep 2, 2016)

When you say "lead acid" are you saying it's a flooded cell battery, and not the AGM style battery the car was designed to use? The battery charging profile for a flooded cell is different than an AGM. It's entirely possible to recover a dead battery. Now at those temperatures a flooded cell would typically freeze if drained as you described, and freezing typically does damage to the plates inside the cells. As far as what got the battery drained.. I might guess the Bluetooth issue that some have mentioned is a possible culprit. If you are active on a Bluetooth call when you shut off the car, apparently the Bluetooth will stay active and not shut off even after you get out of the car. Just a guess on my part. 

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## oreo382 (Sep 17, 2014)

Well,after charging overnight,6 amps for 4 hours and 2 amp setting overnight same thing just happened.Car cranked for about 5 seconds,didn't start.Went to try again,cranked for a couple of seconds and click,click,click,no crank.Have just put the 6 amp charge on again,hopefully will start and back to the battery store.Its a flooded lead,silver,calcium.They have a high charging voltage that's ok with our systems according to the battery store.They have been in business for about 40 years,i hope i can trust their knowledge.Battery issue aside,cranking for a few seconds would normally start the car.I wonder if there is something going on with the glow plugs.I know a couple of times i forgot to wait and the car cranked a long time before starting.I could see with a combination poor battery and poor glow plugs this happening.


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## Rivergoer (Mar 30, 2017)

Before looking at anything else, I would take the flooded cell battery in and request pro-rated credit (1 year) toward the correct AGM replacement battery normally specified for the diesel.


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## MRO1791 (Sep 2, 2016)

You need the AGM battery. An AGM has both a high amp capacity and a deep discharge capability. The flooded cell can be a high CCA for starting, or a deep cycle with deep discharge, but not both in the same battery. This car was designed for the AGM and that is what it needs. Who ever sold that battery did not know about the Diesel specific Cruze system. It's not at all like the gasoline car. In Gen 2 a flooded cell would even be dangerous, as it's inside the trunk and a flooded cell off gasses, corrosive, and possible explosive gas and must be in a ventilated space only. 

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## MiniMax (May 30, 2017)

I had the same issue happen to me this morning. My Diesel Cruze is a 2015 and has the original battery. It was 10 F out this morning and would not start. Turned over for a few seconds and then died. I have a brand new Red Top Optima that I am going to try tonight. This might be off topic but has anyone ever had a block heater added to their diesel? Does it help?


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## boraz (Aug 29, 2013)

MiniMax said:


> I had the same issue happen to me this morning. My Diesel Cruze is a 2015 and has the original battery. It was 10 F out this morning and would not start. Turned over for a few seconds and then died. I have a brand new Red Top Optima that I am going to try tonight. This might be off topic but has anyone ever had a block heater added to their diesel? Does it help?


one guy put a circulation heater in his ctd

its not gonna help with starting, just give you heat sooner, and perhaps lead to more codes as the car will not know why the coolant is so warm vs ambient temp vs time running etc...cant member if that guy got the codes sorted out or not.

the oil in the car is rated waay colder than 10f, ive started the car -51f not plugged in no problem...if your battery is up to par, and your fuel is up to par, 10f is nothing.


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## MiniMax (May 30, 2017)

boraz said:


> one guy put a circulation heater in his ctd
> 
> its not gonna help with starting, just give you heat sooner, and perhaps lead to more codes as the car will not know why the coolant is so warm vs ambient temp vs time running etc...cant member if that guy got the codes sorted out or not.
> 
> the oil in the car is rated waay colder than 10f, ive started the car -51f not plugged in no problem...if your battery is up to par, and your fuel is up to par, 10f is nothing.


So then it must be my battery. I will be testing it with a battery I have on my truck, a brand new Red Top Optima. Hopefully this fixes the issue.


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## oreo382 (Sep 17, 2014)

MiniMax said:


> I had the same issue happen to me this morning. My Diesel Cruze is a 2015 and has the original battery. It was 10 F out this morning and would not start. Turned over for a few seconds and then died. I have a brand new Red Top Optima that I am going to try tonight. This might be off topic but has anyone ever had a block heater added to their diesel? Does it help?


Well it turns out it is the battery.Went back to the store after getting the car started and they tested it with a cca reading instrument which read 500cca.As a second test they then got me to start the car,turn on the hi beams and heater to full and watched the battery voltage slowly dropping,the alternator couldn't keep up.They changed the battery (another lead acid) and she starts now.I have no idea why the first load test showed good other than the tech didn't have the load current set high enough.I did notice the old battery voltage would jump up to >15 volts almost immediately after starting.The new one goes up there if the temperature is below 0 but it does it much more slowly.As for the have to have an AGM battery replys,flooded batterys have been starting diesels for a long time,much larger diesels than the 2L Cruze.Admittedly the big ones use 2 batteries but the diesels are like 6L,3x the displacement of the Cruze.I've got 1 year free replacement left on this battery,if it starts to act up then i'll go buy a Northstar and be done with it.


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## MRO1791 (Sep 2, 2016)

oreo382 said:


> Well it turns out it is the battery.Went back to the store after getting the car started and they tested it with a cca reading instrument which read 500cca.As a second test they then got me to start the car,turn on the hi beams and heater to full and watched the battery voltage slowly dropping,the alternator couldn't keep up.They changed the battery (another lead acid) and she starts now.I have no idea why the first load test showed good other than the tech didn't have the load current set high enough.I did notice the old battery voltage would jump up to >15 volts almost immediately after starting.The new one goes up there if the temperature is below 0 but it does it much more slowly.As for the have to have an AGM battery replys,flooded batterys have been starting diesels for a long time,much larger diesels than the 2L Cruze.Admittedly the big ones use 2 batteries but the diesels are like 6L,3x the displacement of the Cruze.I've got 1 year free replacement left on this battery,if it starts to act up then i'll go buy a Northstar and be done with it.


It's not about the ability to start the car that is the issue. This car has a computer controlled alternator that alters charging to charge on deceleration and then discharge when you accelerate. This is done to add to MPG. It however means that the battery is going through constantly charging and discharging cycles when you drive it. Until very recently all cars had a near constant 14.4 volt system when running, which is what works well for a flooded cell. If you like changing batteries frequently and causing stress to your starting and charging system for early starter and alternator failure, then go ahead stick with the flooded cell old technology that wasn't part of the program for the electrical system of THIS car. It's not about starting, or it being a diesel. The system was designed for an AGM, and they handle much higher charging rates without damage, can do many more charge/discharge cycles than flooded cells. The Navy even ditiched flooded cell technology on submarines. It's not the right battery for this car. 

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## obermd (Mar 3, 2012)

oreo382 said:


> Well it turns out it is the battery.Went back to the store after getting the car started and they tested it with a cca reading instrument which read 500cca.As a second test they then got me to start the car,turn on the hi beams and heater to full and watched the battery voltage slowly dropping,the alternator couldn't keep up.They changed the battery (another lead acid) and she starts now.I have no idea why the first load test showed good other than the tech didn't have the load current set high enough.I did notice the old battery voltage would jump up to >15 volts almost immediately after starting.The new one goes up there if the temperature is below 0 but it does it much more slowly.As for the have to have an AGM battery replys,flooded batterys have been starting diesels for a long time,much larger diesels than the 2L Cruze.Admittedly the big ones use 2 batteries but the diesels are like 6L,3x the displacement of the Cruze.I've got 1 year free replacement left on this battery,if it starts to act up then i'll go buy a Northstar and be done with it.


Get it replaced now with an AGM battery. The old flooded cell Lead Acid batteries won't work in the Cruze, or in just about any other late model car for that matter. It's not about how much starting power is needed, it's how the battery is managed by the car. The Cruze has a variable output alternater, which means that the battery won't be receiving a consistent 14.4v for charging. Instead, it will receive anywhere from 13.5 to 15.6v for charging based on the load on the engine. Lead acid batteries simply can't handle this variable charge rate.


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## IndyDiesel (May 24, 2015)

Whoever did the service in the car should be put out of business, they are not qualified to work on anyone’s car. I am amazed how folks buy a car and then can’t seem to understand how to maintain it properly. My dad is 80 now and his first real job was a Ford mechanic at a dealership. I am so thankful for everything he taught me. I am not a gear head but I understand how to do basic stuff and get repairs done properly.


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## Blasirl (Mar 31, 2015)

[h=1]Cruze Battery Upgrade Options[/h]


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## oreo382 (Sep 17, 2014)

The gas Cruzes came with flooded lead acid batteries and have the same charging algorithm (smaller alternator current output though).I've looked this up in Chilton's service manual for both the gas and diesel cruzes so your statement of not working is not correct.My Cruze output is 15 volts when the temp is below zero celsius which is fine for a flooded battery.Look up the charging specs. for them at low temps and see for yourself.Optima batteries in one of their q&a's about AGM battery charging were asked what charger setting to use if there is a standard (flooded) and gel setting on a charger.Their reply was to use the standard (flooded) setting.So the AGM and floodeds are not that much different as far as charging,they're both lead acid.Another thing to put in your pipe,AGM's can't tolerate charging above a certain ambient (120F) temperature as well as floodeds.Manufacturers state this in their literature,look it up.Underhood summer temps are more than 120F.No wonder there are a lot of Cruze Diesel battery failures.AGM's are great in the trunk.I'm sure the manufacturers don't mind as they can sell more.


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## sailurman (Sep 29, 2016)

oreo382 said:


> The gas Cruzes came with flooded lead acid batteries and have the same charging algorithm (smaller alternator current output though).I've looked this up in Chilton's service manual for both the gas and diesel cruzes so your statement of not working is not correct.My Cruze output is 15 volts when the temp is below zero celsius which is fine for a flooded battery.Look up the charging specs. for them at low temps and see for yourself.Optima batteries in one of their q&a's about AGM battery charging were asked what charger setting to use if there is a standard (flooded) and gel setting on a charger.Their reply was to use the standard (flooded) setting.So the AGM and floodeds are not that much different as far as charging,they're both lead acid.Another thing to put in your pipe,AGM's can't tolerate charging above a certain ambient (120F) temperature as well as floodeds.Manufacturers state this in their literature,look it up.Underhood summer temps are more than 120F.No wonder there are a lot of Cruze Diesel battery failures.AGM's are great in the trunk.I'm sure the manufacturers don't mind as they can sell more.



:banghead:k:

Wow, thanks for straightening us all out. I don't know what these silly people with all this education and experience were thinking. Whoops, went past 20 words and that's more than I want to invest in somebody that already knows everything.


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## obermd (Mar 3, 2012)

oreo382 said:


> The gas Cruzes came with flooded lead acid batteries and have the same charging algorithm (smaller alternator current output though).I've looked this up in Chilton's service manual for both the gas and diesel cruzes so your statement of not working is not correct.My Cruze output is 15 volts when the temp is below zero celsius which is fine for a flooded battery.Look up the charging specs. for them at low temps and see for yourself.Optima batteries in one of their q&a's about AGM battery charging were asked what charger setting to use if there is a standard (flooded) and gel setting on a charger.Their reply was to use the standard (flooded) setting.So the AGM and floodeds are not that much different as far as charging,they're both lead acid.Another thing to put in your pipe,AGM's can't tolerate charging above a certain ambient (120F) temperature as well as floodeds.Manufacturers state this in their literature,look it up.Underhood summer temps are more than 120F.No wonder there are a lot of Cruze Diesel battery failures.AGM's are great in the trunk.I'm sure the manufacturers don't mind as they can sell more.


Chilton's is wrong in this case. The battery that came with my 2012 ECO MT was AGM.


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## oreo382 (Sep 17, 2014)

obermd said:


> Chilton's is wrong in this case. The battery that came with my 2012 ECO MT was AGM.


 Read up on the Gas Cruze forum,that's where I learned that bit.The part about the algorithm is from Chiltons and if you think that's wrong then read up again on the gas forum and there is info about the charging scheme.The ECO may be different (weight saving?)


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## oreo382 (Sep 17, 2014)

No, I don't know "everything",just that you spout out some b.s. about batteries not working in any cars.Show some proof.BTW the sarcasm attack is typical of a person with no backup to their statements.


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## obermd (Mar 3, 2012)

oreo382 said:


> Read up on the Gas Cruze forum,that's where I learned that bit.The part about the algorithm is from Chiltons and if you think that's wrong then read up again on the gas forum and there is info about the charging scheme.The ECO may be different (weight saving?)


The charging algorthyms are correct - just the OEM battery info. GM started transitioning from Lead Acid batteries in the late 90s - my 2002 Pontiac Montana had an AGM battery from the factory.


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## dougunder (May 24, 2018)

That's just diesel's dude. Cold weather puts an unbelievable strain on batteries.
That's the nature of pure compression cycle.

Plus side you never pay for batteries, just keep those receipts. Free new battery almost every winter!

If stuck charge the battery then jump it. That should give you enough umph to lite the glow plugs and spin fast enough.

At least new ones start in the winter. The old manual injection pump motors were a nightmare if you forgot to plug in the block heater.
More then once I stuck a hibachi under my old VW rabbit...


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## MRO1791 (Sep 2, 2016)

https://www.batterystuff.com/kb/articles/battery-articles/battery-basics.html


Read up those of you who are claim there is no difference for AGM. There is a reason the Navy switched away from flooded cell.. and many OEMs are for cars as well. Ability to take more charge and discharge cycles, and more efficiently. Can handle much higher charging rates, etc. And to properly change they have a different charging profile than the classic flooded cell battery. 

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## jblackburn (Apr 14, 2012)

obermd said:


> Chilton's is wrong in this case. The battery that came with my 2012 ECO MT was AGM.


Mine wasn't. It was the crappy AC Delco 438 CCA they left the factory with. Yours was probably switched out by the dealer if the car sat on the lot a while - my Gen 2 had been switched out. They later switched Gen 1's to the 525 CCA lead acid batteries since the 438s were dying left and right. 

The trunk/underhood temp thing is a good explanation for why they moved the battery in the Gen 2. They require an AGM battery for the start/stop system. 

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## sailurman (Sep 29, 2016)

oreo382 said:


> No, I don't know "everything",just that you spout out some b.s. about batteries not working in any cars.Show some proof.BTW the sarcasm attack is typical of a person with no backup to their statements.


Have to be careful of wasting word count.... No. This sarcasm attack is typical of me addressing somebody in way over their head and unwilling to back down.(20...perfect)


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## oreo382 (Sep 17, 2014)

Over their head,read the post above yours.


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## Ma v e n (Oct 8, 2018)

oreo382 said:


> The gas Cruzes came with flooded lead acid batteries and have the same charging algorithm (smaller alternator current output though).I've looked this up in Chilton's service manual for both the gas and diesel cruzes so your statement of not working is not correct.My Cruze output is 15 volts when the temp is below zero celsius which is fine for a flooded battery.Look up the charging specs. for them at low temps and see for yourself.Optima batteries in one of their q&a's about AGM battery charging were asked what charger setting to use if there is a standard (flooded) and gel setting on a charger.Their reply was to use the standard (flooded) setting.So the AGM and floodeds are not that much different as far as charging,they're both lead acid.Another thing to put in your pipe,AGM's can't tolerate charging above a certain ambient (120F) temperature as well as floodeds.Manufacturers state this in their literature,look it up.Underhood summer temps are more than 120F.No wonder there are a lot of Cruze Diesel battery failures.AGM's are great in the trunk.I'm sure the manufacturers don't mind as they can sell more.


LMFAO!!!....Chilton's...There's a resource.

First of all, the Chilton 28512 manual specifically States in its description it doesn't include diesel specific information...Secondly I'd be willing to wager the word "algorithm" doesn't appear once in the manuals 320 pages.
320 pages and $25.....What a joke, the factory service manual is well over 2000pages and $375....And even it doesn't provide information regarding specifics of the charging algorithm beyond the differing modes of the regulated voltage control system. 

So until you provide the lines of code you deciphered, or engineering documents specifying the intended RVC algorithms, you're statements of fact are undefendable bullshit.


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## oreo382 (Sep 17, 2014)

The different modes of the battery charging voltage control is the algorithm and is the same for both diesel and gas Cruzes.The ChiltonDiy thru my city library online does include diesel specific repair information.Maven aka Sailurman.


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## MRO1791 (Sep 2, 2016)

Hmmm, way back when I had a 1984 Chevette and a Chilton manual...it didn't include wiring diagrams for that car, with a statement that it was too complicated!! Compared to today's cars that was a Flinstones mobile. It also had the transmission wrong, my brother following the book removed the drain plug looking to verify level on what the manual said was the fill plug... I guess it sort of worked... It WAS full... Then it wasn't! I would not trust a Chilton manual for the complexity of the electrical system on this car. 

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## Ma v e n (Oct 8, 2018)

oreo382 said:


> The different modes of the battery charging voltage control is the algorithm and is the same for both diesel and gas Cruzes.The ChiltonDiy thru my city library online does include diesel specific repair information.Maven aka Sailurman.


The different modes are not an algorithm...They are the different operating modes. Even the factory service manual doesn't tell what the algorithm is, nor does it even tell what level of amperage and voltage output is aimed for during any given mode. This algorithmic information you claim to have gleaned from a Chilton manual doesn't exist outside of GM engineering information, save for anyone who has gone through the lines of code in the control modules.

I can assure you that I am not AKA as Sailurman.


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## oreo382 (Sep 17, 2014)

FYI an algorithm " a process or set of rules to be followed in calculations or other problem-solving operations, especially by a computer." Here's from the crappy Chiltons online for the Cruzes (diesel and gas):[FONT=&quot]The purpose of the charging system is to maintain the battery charge and vehicle loads. There are 6 modes of operation and they include:[/FONT][FONT=&quot]

Battery Sulfation Mode

Charge Mode

Fuel Economy Mode

Headlamp Mode

Start Up Mode

Voltage Reduction Mode
The engine control module (ECM) controls the generator through the generator turn ON signal circuit. The ECM monitors the generator performance though the generator field duty cycle signal circuit. The signal is a pulse width modulation (PWM) signal of 128 Hz with a duty cycle of 0–100 percent. Normal duty cycle is between 5–95 percent. Between 0–5 percent and 95–100 percent are for diagnostic purposes. The following table shows the commanded duty cycle and output voltage of the generator:


Commanded Duty CycleGenerator Output Voltage10%
11 V
20%
11.56 V
30%
12.12 V
40%
12.68 V
50%
13.25 V
60%
13.81 V
70%
14.37 V
80%
14.94 V
90%
15.5 V

The generator provides a feedback signal of the generator voltage output through the generator field duty cycle signal circuit to the ECM. This information is sent to the body control module (BCM). The signal is PWM signal of 128 Hz with a duty cycle of 0–100 percent. Normal duty cycle is between 5–99 percent. Between 0–5 percent and 100 percent are for diagnostic purposes.
The BCM will enter this mode when the interpreted generator output voltage is less than 13.2 V for 45 minutes. When this condition exists the BCM will enter Charge Mode for 2–3 minutes. The BCM will then determine which mode to enter depending on voltage requirements.
The BCM will enter Charge Mode when ever one of the following conditions are met.


The wipers are ON for more than 3 seconds.

GMLAN (Climate Control Voltage Boost Mode Request) is true, as sensed by the HVAC control head. High speed cooling fan, rear defogger and HVAC high speed blower operation can cause the BCM to enter the Charge Mode.

The estimated battery temperature is less than 0°C (32°F).

Battery State of Charge is less than 80 percent.

Vehicle speed is greater than 145 km/h (90 mph)

Current sensor fault exists.

System voltage was determined to be below 12.56 V
When any one of these conditions is met, the system will set targeted generator output voltage to a charging voltage between 13.9–15.5 V, depending on the battery state of charge and estimated battery temperature.
The BCM will enter Fuel Economy Mode when the estimated battery temperature is at least 0°C (32°F) but less than or equal to 80°C (176°F), the calculated battery current is less than 15 amperes and greater than −8 amperes, and the battery state-of-charge is greater than or equal to 80 percent. Its targeted generator output voltage is the open circuit voltage of the battery and can be between 12.5–13.1 V. The BCM will exit this mode and enter Charge Mode when any of the conditions described above are present.
The BCM will enter Headlamp Mode when ever the headlamps are ON (high or low beams). Voltage will be regulated between 13.9–14.5 V.
When the engine is started the BCM sets a targeted generator output voltage of 14.5 V for 30 seconds.
The BCM will enter Voltage Reduction Mode when the calculated ambient air temperature is above 0°C (32°F). The calculated battery current is less than 1 ampere and greater than −7 amperes, and the generator field duty cycle is less than 99 percent. Its targeted generator output voltage is 12.9 V. The BCM will exit this mode once the criteria are met for Charge Mode.
Charge Indicator Operation
The instrument panel cluster illuminates the charge indicator and displays a warning message in the driver information center if equipped, when the one or more of the following occurs:


The engine control module (ECM) detects that the generator output is less than 11 V or greater than 16 V. The instrument panel cluster receives a GMLAN message from the ECM requesting illumination.

The instrument panel cluster determines that the system voltage is less than 11 V or greater than 16 V for more than 30 seconds. The instrument panel cluster receives a GMLAN message from the body control module (BCM) indicating there is a system voltage range concern.

The instrument panel cluster performs the displays test at the start of each ignition cycle. The indicator illuminates for approximately 3 seconds.
Display Message: BATTERY NOT CHARGING SERVICE CHARGING SYSTEM or SERVICE BATTERY CHARGING SYSTEM
The BCM and the ECM will send a serial data message to the driver information center for the BATTERY NOT CHARGING SERVICE CHARGING SYSTEM or SERVICE BATTERY CHARGING SYSTEM message to be displayed. It is commanded ON when a charging system DTC is a current DTC. The message is turned OFF when the conditions for clearing the DTC have been met.
I'm done with you two.








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## Ma v e n (Oct 8, 2018)

Well, I will admit that's not typical Chilton's info. That appears to be cribbed directly and word for word from the GM Service Information/Manual. I guess their online product is better than their paper one. Good for them

That still isn't an algorithm. It merely the description of the operation of the system and the nomeclature used for it's modes. Which is literally what I stated was contained in the GM Service Information. Your post of this information proves my point. There's no algorithm.

An algorithm as Google told you, is a "process or set of rules to be followed in calculations or other problem-solving operations" you've merely provided the description of the actions the vehicle can take, based on the results of the calculations the modules perform. Outputs are different than calculations, are different than algorithms.

And non of this changes the fact that GM treats/charges/conditions/tests AGM batteries different than traditional lead acid SLI batteries. From the required battery for the vehicle, to the test equipment and modes required to be used to charge, condition and test AGM batteries.

Note I've never said that lead-acid battery choice was the reason for your particular failure. That was likely just a defective battery.


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## Ma v e n (Oct 8, 2018)

You also keep mention battery and charging voltages. A key difference between AGM and traditional flodded batteries is that AGM typically have a lower internal resistance. This internal resistance is what affects charging rate and amperage discharge and draw rates. It why AGM programming profiles are different.

A simple open circuit voltage reading doesn't take into account or measure resistance. A battery with an internal resistance of 15mOhms, would measure the same voltage as one with 16mOhms resistance, it's performance would vary a great deal. That measly .001 ohm resistance change to the internal plates would be nearly impossible to measure with a typical handheld DVOM(digital volt-ohm meter) but it would reduce the maximum available amperage to the vehicle by more than 50 amps. The same difference in resistance would also limit the amount of current going into the battery to maintain it's charge level.


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## oreo382 (Sep 17, 2014)

Ma v e n said:


> You also keep mention battery and charging voltages. A key difference between AGM and traditional flodded batteries is that AGM typically have a lower internal resistance. This internal resistance is what affects charging rate and amperage discharge and draw rates. It why AGM programming profiles are different.
> 
> A simple open circuit voltage reading doesn't take into account or measure resistance. A battery with an internal resistance of 15mOhms, would measure the same voltage as one with 16mOhms resistance, it's performance would vary a great deal. That measly .001 ohm resistance change to the internal plates would be nearly impossible to measure with a typical handheld DVOM(digital volt-ohm meter) but it would reduce the maximum available amperage to the vehicle by more than 50 amps. The same difference in resistance would also limit the amount of current going into the battery to maintain it's charge level.


Cruzes measure the charging current and regulate it by pulse width modulating the alternator output so if your flooded battery has a .001 ohm greater resistance (by your logic) the alternator will output more to maintain the current.BTW there are manufacturing tolerances for batteries,not all AGM's would be dead on 15mohms.In addition the fuses,cables,bolted connections all add up to a few milliohms so in the big scheme 1mohm out of say 20 mohms is what,5%.5% of 10 amps charging current is 1/2 amp.I don't think that will severely under or over charge an AGM vs a flooded.In addition CCA is CCA,a flooded battery with 800CCA has the same current output as an 800CCA AGM battery.


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## MRO1791 (Sep 2, 2016)

Battery sulfation mode should never be used for AGM... So either that Clinton / GM Service manual is overly generalized and not vehicle model specific, or GM is negligent in running a one size fits all charging system that can actually damage an AGM battery and putting AGM in the diesel model. Sulfation is not an issue with AGM and those higher voltages can damage AGM. In fact the manufacturer of of AGM, Enersys (Odessey) has a list of approved chargers, and they have specific AGM operating modes for this reason. 

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## MRO1791 (Sep 2, 2016)

https://www.knowyourparts.com/technical-resources/blog/three-misconceptions-agm-batteries/

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## MRO1791 (Sep 2, 2016)

https://batteryuniversity.com/learn/article/absorbent_glass_mat_agm

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## plano-doug (Jul 1, 2015)

MRO1791 said:


> https://batteryuniversity.com/learn/article/absorbent_glass_mat_agm


Thanks for the link. I read the article ( but opted to forego most of the comments below it  )

I have two Cruzes, but until now, have been totally oblivious to this change in battery technology. I need to go look and see what type batteries are installed.

[Edit] I checked - I think mine are both standard lead-acid. But neither car is diesel, nor stop-start. So I doubt the AGM applies in my case, no ?

Doug

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## oreo382 (Sep 17, 2014)

As for GM being negligent,here's a quote from the "battery university" article link you supplied. "AGM and other sealed batteries do not like heat and should be installed away from the engine compartment. Manufacturers recommend halting charge if the battery core reaches 49°C (120°F)."
So with that thinking,Cruze's AGM's are under the hood and I can bet the temps. under there in the summer are way higher than 120F.I wonder if that is why we see so many failed ones on this forum.Maybe the Delco batteries are good after all and its the underhood application that's killing them prematurely.Some have replaced theirs with different mfr's. AGM's,it will be interesting to see if they fail in acouple of years as well.I know a lot of car mfr's. have AGM's in the trunk.


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## MRO1791 (Sep 2, 2016)

plano-doug said:


> Thanks for the link. I read the article ( but opted to forego most of the comments below it  )
> 
> I have two Cruzes, but until now, have been totally oblivious to this change in battery technology. I need to go look and see what type batteries are installed.
> 
> ...


The install for AGM from the factory appears to be a diesel only requirement. So you would not need an AGM, but you could possibly use one. I put them in my Diesel Truck, originally it had Lead Acid. I can't be 100% sure it was a good move yet, the original batteries lasted about 8 years and were not completely gone when I replaced them, in fact I kept one and now it's 10 years old and can start my 04 Land Rover. The first Odessey AGMs in my truck died after 1 year, but replaced for free under warranty. They are under hood, with a heat shield and temperature adjusted charging from the OEM, which lowers voltage when the battery gets warm. As to early AGM failures on Gen 1 Diesel, yep that's real. At one point I had two 2015s, Diesels and I early replaced both batteries as they were starting to show signs of weakness with poor cranking. I can absolutely see the under hood temperature being an issue, especially with 1200F DPF Regen under the hood and only inches away... 
I did some work on the truck to include insulation on the turbo and exhaust that has helped lower under hood temperatures.

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## MRO1791 (Sep 2, 2016)

oreo382 said:


> As for GM being negligent,here's a quote from the "battery university" article link you supplied. "AGM and other sealed batteries do not like heat and should be installed away from the engine compartment. Manufacturers recommend halting charge if the battery core reaches 49°C (120°F)."
> So with that thinking,Cruze's AGM's are under the hood and I can bet the temps. under there in the summer are way higher than 120F.I wonder if that is why we see so many failed ones on this forum.Maybe the Delco batteries are good after all and its the underhood application that's killing them prematurely.Some have replaced theirs with different mfr's. AGM's,it will be interesting to see if they fail in acouple of years as well.I know a lot of car mfr's. have AGM's in the trunk.


Yes, I think under hood temperature could be an issue on Gen 1, mentioned in my previous comment. 

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