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LOL...what he said ^^^
I've only run SLA batteries as equipped from the factory. Generally less expensive and meets the vehicle requirements.
 
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'12 CTS Performance Sports Wagon AWD
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With a standard battery, you kill it below about 9volts once requiring a jump, you have halfed its lifespan. The 14.5 volts that the CTS charges is well within the charging parameters of an AGM battery. The "smart" feature of the CTS will back off the charging possibly a little sooner on an AGM battery but not a bad thing. The AGM batteries are more durable and able to take more of a beating. This includes with charging as well. Even if the smart charging system in the CTS is not "perfect" for the AGM, the other characteristics of an AGM battery will mean it likely still will outlast a standard battery in normal usage. Much longer in abused usage. And if you end up needing to jump an AGM, it should accept the "jump" easier than a standard battery as well as not be as 'damaged'. I abuse the ones I have in my truck and they far outlast a standard battery. I will kill a standard battery in a year in my truck due to limited driving etc... The AGM's I have in it now have lasted 2 years and still strong as they were new.
 
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The 14.5 volts that the CTS charges is well within the charging parameters of an AGM battery
Double check and make sure. The first time I treated an AGM battery like a flooded lead acid battery, by charging it with a regular charger, I burned it up quickly. It started gassing and heating up. I did a little reading on it immediately after that incident and discovered that the particular AGM battery I had (Sears Platinum) was restricted to a 13.6v charge rate, and most non AGM oriented chargers, charge at upwards of 16-18 volts at the clamps from my own multimeter check. Usually modern chargers on the market today will have an AGM specific charge setting.
 

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AGM batteries are not worth the extra upfront premium IMO for our cars.
I'm not looking to start a war here, just stating the obvious.
 

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I'm not looking to start a war here, just stating the obvious.
X2
They tend to last longer and perform better, although regular SLA works fine.
I still work with auto repair a little and I am not seeing that in new vehicles equipped with AGM batteries. It seems they have them because they need them to support all of the extra and are still being used up in about the same amount of time as non AGM batteries. They're certainly not worth the extra weight they carry along with the hefty price to me.
 

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2014 CTS4 Sport Wagon*2016 CTS V-Sport Premium
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I've had both AGM batteries (in cars that came with them) and non AGM/SLA batteries...my Deltran Battery Tender Plus battery charger/maintainer/exerciser allows for charging AGM batteries and I've read where some chargers are okay with AGM and some are not...

I don't see the need for paying extra for the AGM battery to fit our Gen2 CTS (my Gen3 CTS V-Sport has one installed by previous owner) and I would purchase either a Costco/Interstate or a Walmart Everstart Maxx whichever was easier and less expensive for me...

my CTS Sport Wagon currently has a Menard's AC Delco battery that has given me no issues in the 3.5 years it's been in but the CA/CCA and RC and AH numbers are slightly lower than they would be in the Interstate and Everstart Maxx batteries made by Clarios

Good luck with your choice

Bill
 

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2011 CTS coupe 1989 Allante
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I buy only better AGM batteries. When I bought the coupe in '18 I replaced the Duralast Gold with a Duracell platinum AGM. Put the Duralast in my Jeep tow car. Is still there.
BTW I prefer the NOCO Genius 1 trickle charger. It has SLA, AGM, and Lithium settings plus "force" for a ded battery and 6v positions. Have 6 now, bought when Amazon has on sale for under $20.
 

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2009 CTS 3.6L DI, 2014 CTS VSport
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I still work with auto repair a little and I am not seeing that in new vehicles equipped with AGM batteries. It seems they have them because they need them to support all of the extra and are still being used up in about the same amount of time as non AGM batteries. They're certainly not worth the extra weight they carry along with the hefty price to me.
Batteries are a well-understood technology. The fact that AGM can source greater current, charge faster, last longer, don't self-discharge as quickly, and recombine unwanted gasses to water are all characteristics proven by industry - not just opinions on a car forum. Our modern charging systems are aware of both voltage and current into and out of the battery, easily accomodating the slightly different charging regime.

Whether one chooses to pay the price premium is entirely a personal cost/benefit analysis.
 
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Batteries are a well-understood technology. The fact that AGM can source greater current, charge faster, last longer, don't self-discharge as quickly, and recombine unwanted gasses to water are all characteristics proven by industry - not just opinions on a car forum. Our modern charging systems are aware of both voltage and current into and out of the battery, easily accomodating the slightly different charging regime.

Whether one chooses to pay the price premium is entirely a personal cost/benefit analysis.
To be clear, I'm not under the influence of car forum opinions on this subject, I'm not questioning tech performance, I'm going by what I have observed personally. Our smart charging systems knowing battery voltage vs. knowing the required charge specifications of any given battery design (like BMW battery related programming requirements) are two different things.

Did GM program the system of our non AGM spec cars to optimize the charging system for one? I have no idea. I know most later model vehicles with AGM specified batteries more often than not have a lot more going on with the positive battery cable than what my car does, and I've seen at least one with a probe on both positive and negative battery cables. I have an AGM battery in my car, It would need to last 5 yrs in order for me to consider replacing it with another.
I don't suppose all AGM batteries are created equal either, which can account for some performance variations.
 

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2011 CTS4 Coupe, 2014 ELR, 2018 XT5 AWD
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GM's first generation smart charging system senses battery charging current using an inductive loop installed on the negative ground cable between the negative battery cable and all ground points it is connected to. The system senses battery voltage by measuring one of the 12V battery inputs to the BCM.
The second generation smart charging system uses an integrated battery sensor - IBS that is built into the negative battery terminal. It is powered by its own small fuse that is normally right in the battery distribution unit - BDU on top of the battery. The IBS is a small computer that measures battery current and battery voltage. It also wakes up after the vehicle has been parked for approximately 4 hours to make a battery open circuit voltage measurement. That measurement is used to calculat the battery state of charge. This state of charge along with the other information provided by the IBS is communicated to the BCM via LIN protocol.
 

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2009 CTS 3.6L DI, 2014 CTS VSport
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Our smart charging systems knowing battery voltage vs. knowing the required charge specifications of any given battery design (like BMW battery related programming requirements) are two different things.
This seems to be a common misconception, that it is necessary for a charging system to "know" about slight variations in very similar battery chemistries, and it is necessary the battery configuration (I won't say chemistry, because it's the same) be "programmed" into the charger.

That isn't how it works. Battery voltages vary slightly with temperature, and with battery type; SLA, AGM, or Lead/Calcium. Indeed, this is exactly the problem one faces with a dumb charging system. They don't even work well with a single designed battery type, like SLA, as they don't account for voltage variations at different charging stages by measuring current.

Rather than regurgitate widely understood knowledge of battery charging algorithms, I'll post a graph and link. One can do further reading if desired. The short version is, push the voltage up till the current drops. Note that is not "push the voltage up to 14.8V for an SLA battery, or 15.0V for an AGM battery, or 15.0V for an SLA battery at 35F ambient temperature".

 

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This seems to be a common misconception, that it is necessary for a charging system to "know" about slight variations in very similar battery chemistries, and it is necessary the battery configuration (I won't say chemistry, because it's the same) be "programmed" into the charger.

That isn't how it works. Battery voltages vary slightly with temperature, and with battery type; SLA, AGM, or Lead/Calcium. Indeed, this is exactly the problem one faces with a dumb charging system. They don't even work well with a single designed battery type, like SLA, as they don't account for voltage variations at different charging stages by measuring current.

Rather than regurgitate widely understood knowledge of battery charging algorithms, I'll post a graph and link. One can do further reading if desired. The short version is, push the voltage up till the current drops. Note that is not "push the voltage up to 14.8V for an SLA battery, or 15.0V for an AGM battery, or 15.0V for an SLA battery at 35F ambient temperature".

Appreciate the visual, but that charge algorithm chart is for the charging module represented in the link, not necessarily what our non AGM spec cars are programmed to deliver, although reasonable I suppose to assume, even in a car that disables and then recommends servicing power steering when the alternator fails. Not a very convincing "smart charge" system.

None the less, I've read a few references to the AGM being longer lived and even lighter in weight (no way) and I have yet to see that born out within the contact I've had with the equipment. A little over a week ago I stated they didn't appear to be worth the investment in a non required application, because of the manufacture date vs. failure date. To be fair, I would have to compare the traditional battery's performance in the same application. Perhaps that's where the benefit would be better demonstrated and again, variation in quality due to retailer's manufacture requirements must be recognized.
 

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Appreciate the visual, but that charge algorithm chart is for the charging module represented in the link, not necessarily what our non AGM spec cars are programmed to deliver, although reasonable I suppose to assume, even in a car that disables and then recommends servicing power steering when the alternator fails. Not a very convincing "smart charge" system.
The battery determines what charging algorithm is appropriate. The algorithm shown is fairly universal across various chargers, because lead acid batteries want similar charging behavior. Which you would know if you looked into the subject.

I have two very different chargers with exactly the algorithm shown, which is correct for all lead acid batteries with the possible exception of gel.
 

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In MY experience the AGM batteries take much more abuse than a standard battery and last MUCH longer in my truck than standard batteries. I have been known to kill a standard battery in under 2 years because I park the truck in the winter and just pull the negative terminal. The second winter I end up with a weak battery... You would think they shouldn't discharge but dunno. With the AGM's I have one in my truck that has been in there 3 years under same terms and still running strong. The standard battery I bought because I couldn't find the proper AGM (Supply chain issues) Died and had to be replaced and the AGM i replaced prior is still running strong a year later. Truck has 2 AGM batteries in it now each with its own "dumb" alternator. So I am sold on them. Now that I am working remote my car seems to hold its charge longer in the winter with the AGM than a standard battery. I replaced a 4 year old standard battery last year because it wouldn't stay charged if I didn't drive the car for 3-4 days. This AGM has been great for over a week.
 
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Battery maintainers.
Worth every penny.
Dont do any good if you don't have a garage and can't plug it in...
 
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