[Steverino]

Quick Answers:

1. What battery does the Gen 1 (2011-2015), need? AGM BCI Group 47, GENERAL MOTORS OE Part Number: 88864595
2. How do I replace the battery? See general info below.
3. Pros and Cons of AGM Batteries? Pro: Longevity, Safety. Con: Cost
4. Does the battery have vent/overflow hose connected to it? Yes
5. What if I think my battery has a problem? Take to dealer.
6. Can I use a voltmeter/multimeter to determine if the battery is going bad? No
7. Can I replace the original battery with a regular lead-acid battery? No
8. Can I replace the original battery with a Li battery? No
9. Can I use a regular battery charger with the Volt's AGM battery. Probably not
10. Battery Dimensional Specifications, Polarity & Terminals? See details below.
11. Retailer list? See details below.

Detailed Answers
What battery does the Gen 1 (2011-2015), need?
Any AGM that's the right form factor ("Group 47") should be fine. Make sure the negative terminal is toward the car's front right position, positive is front left. When choosing between different batteries, go for highest reserve capacity (the number of minutes a battery can maintain a useful voltage under a 25 ampere discharge) rather than Cold Cranking Amps, or Amp Hours. GENERAL MOTORS OE Part Number: 88864595


How do I replace the battery?
The instructions below are intended as an overview and may not be complete, follow at your own risk.

Battery Disconnect Warning
Warning: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Move the key fob away from the car so it does not wake up any modules. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

For Vehicles equipped with OnStar® (UE1) with Back Up Battery:
The Back Up Battery is a redundant power supply to allow limited OnStar® functionality in the event of a main vehicle battery power disruption to the VCIM (OnStar®module). Do not disconnect the main vehicle battery or remove the OnStar® fuse with the ignition key in any position other than OFF. Retained accessory power (RAP) should be allowed to time out or be disabled (simply opening the driver door should disable RAP) before disconnecting power. Disconnecting power to the OnStar® module in any way while the ignition is On or with RAP activated may cause activation of the OnStar® Back-Up Battery (BUB) system and will discharge and permanently damage the back-up battery. Once the Back-Up Battery is activated it will stay on until it has completely discharged. The BUB is not rechargeable and once activated the BUB must be replaced.

Replacing a battery involves the following safety precautions. Remove all rings and wrist watch. Never short the positive terminal to the negative terminal, or to a metal part of the car while the negative cable is connected to its terminal.

1. Open the rear hatch.
2. Grab the carpeted cargo flap and pull straight up and it'll detach.
3. Turn off all the lamps and accessories.
4. Turn the ignition OFF.
5. Remove the rear compartment floor stowage trim compartment. There are four 10mm bolts, one in each of the 4 corners of that big black plastic tray.
6. Loosen negative cable nut (9 Nm or 80lb in). Remove negative battery cable from battery terminal and reposition cable away from the battery. Clean any existing corrosion from the battery cable end. Bag the exposed metal end in a heavy plastic bag, then wrap that with a towel.
7. Remove the battery vent hose from the battery case. It's located on the negative terminal side of the battery toward the top center.
8. Unlock the retaining tab on the battery fuse box cover (on the positive terminal side).
9. Open the battery fuse box flap. Note: Pull the battery fuse box housing. DO NOT pull the flap.
10. Unlock the retaining tab and open the battery fuse box cover.
11. Remove the battery positive cable to fuse block nut.
12. Reposition the positive battery cable away from the battery.
13. Loosen the battery positive clamp nut (12 Nm, 106 lb in).
14. Remove the fuse block retainer clips and reposition the fuse block.
15. Remove the battery retainer bolt (9Nm, 80 lb in).
16. Remove the battery hold down strap and the hold down retainer.
17. Remove the battery from the rear compartment area.

Putting in the new battery would involve reversing the above steps. Don't forget to install the vent tube.
Dispose of the old battery properly.


Pros and Cons of AGM Batteries?
The biggest con is cost, they are more expensive. Pros (above) are safety and up to a 10 yr life span (depending on heat, etc.). AGM have much lower self-discharge rates than do typical lead-acid wet cells. https://en.wikipedia.org/wiki/VRLA_battery#Absorbed_glass_mat

Does the battery have vent/overflow hose connected to it?
Yes, the original AGM battery has a vent/overflow hose connected to it. If you're going to replace the OEM battery with a third-party one, it needs to have a port that will allow that vent/overflow hose to be connected.

What if I think my battery has a problem?
Take it to a dealer to be properly diagnosed (a tire shop can't do that). If there's something wrong with the battery -it will be tested/verified and if necessary replaced under warranty (assuming the car qualifies). If there's a bad connection- it will be located and repaired. If you are routinely using "Service Mode" for some unknown reason and draining the battery- then that's on you.

Can I use a voltmeter/multimeter to determine if the battery is going bad?
No. You can't tell much about the condition/performance of the AGM battery (or the charging system for that matter) with just a voltmeter. Dealers use an expensive capacitance based test tool called the Midtronics GR8 at the very least you would need an old school carbon-pile load tester
12V battery replaced

I checked at the battery with a digital multimeter. Initial reading on start ramped up to 15.1, then began to drop. After a couple minutes, it was at 14.1 or so. I have seen it running as low as 13.0 and as high as 15.1.
Testing and charging the AGM battery is different from regular lead acid batteries. These voltage readings would be considered 100% normal for the Volt's BCM controlled 12V charging system as it is dependent on a myriad of variables such as temperature, load demand, and basic joule counting. AGM batteries are usually never constantly charged over 14.8V. As long as the rate of charge falls in a few minutes to that range, the system is working as planned.
12V battery replaced

Can I replace the original battery with a regular lead-acid battery?
The Volt uses an AGM (Absorbant Glass Matt) battery. Using a standard 12-volt battery is not recommended. For one, a standard 12-volt battery will result in reduced 12-volt battery life. Two, software driving the charging schedule from the 14V power module (APM) assumes an AGM. Another reason is that the car's starting charge Voltage is 15.1 Volts which can kill all kinds of lead batteries. Three, with the sealed battery and the mat holding things in place, the hydrogen and oxygen recombine back into water with great efficiency - and since the acid isn't a free liquid, it can't do nasty things to people if the battery is broken open in the event of a crash. Four, unlike a lead acid battery, with an AGM you don't need to periodically check the electrolyte levels and add water to them. And five, the AGM will have less hydrogen off-gassing which is potentially explosive in a confined space.

AGM batteries are permanently sealed. The AGM battery uses glass mats that absorb a very small amount of acid (electrolytes) held in place by surface tension and capillary action. The matts are pressed between the plates instead of immersing the plates in electrolytes. This allows for a smaller, lighter battery that is less susceptible to heat but still delivers the same amount of power.

So with AGM, you trade some complexity in construction and cost for a maintenance free battery that's a lot safer in an accident.
More at Online Battery Store | Best Price Batteries, Chargers, Solar Chargers, Terminals, Cables and Accessories!

Can I replace the original battery with a Li battery?
Probably not. Besides an even higher cost (think $1,200), the problem with Lithium as 12V is cold weather. The Volt needs the 12V to run the computer and some other components even if sub-zero weather. The extra cost it would take to build and properly temperature control a separate 12 volt Lithium battery is not justified for the application that the AGM battery serves in the Volt.

Can I use a regular battery charger with the Volt's AGM battery.
Probably not a good idea. The charger has to sense when the battery has reached full charge and taper back the applied voltage accordingly. Make sure that the charger you use is designed to charge AGM batteries. If available, use the “AGM” setting on the charger, to limit charge voltage
to 14.8 volts. The NOCO brand battery chargers provide the proper charging profiles to maintain an AGM battery. A quick google search should line up one if needed.

BCI Group 47 Battery Dimensional Specifications, Polarity & Terminals :
Group: 47
L: 9.70" 246mm
W:6.90" 175mm
H: 7.50" 190mm
Figure:15
Polarity: R/H-POS
Terminals: TOP - SAE AUTO
http://www.batteryweb.com/

Reported Replacement Batteries
AC-Delco EREV BCI Group 47 Starting Battery, Part# EVLN2. Compatibility: GENERAL MOTORS OE Part Number: 88864595
AC-Delco EREV BCI Group 47 Starting Battery, Part# 47AGM. Compatibility: GENERAL MOTORS OE Part Number: 88864083

Above via: http://www.dstgateway.com/ACDelcoDocuments/BatterySpecifications.pdf

Advance Auto Parts AutoCraft Platinum AGM Battery, Group Size H5, Part No. H5-AGM
TRT41 is the discount code
OE Exact Fit; Battery is vented to outside of vehicle.; AGM Valve Regulated Lead Acid (VRLA) is required; Installation may take up to 30 minutes. Battery located in trunk.; OE Spec: OE Group H5 AGM; OE CCA 630; Battery Spec: 60 Ah; Battery Spec: Flat Plate AGM

Batteries Plus Duracell Ultra Platinum AGM, Item# SLI47AGM,
48-month warranty

Deka 9AGM47 12V600CCA
Voltage: 12V
Group No.: 47 (H5/L2)
Cold Cranking Amps: 600
Reserve Capacity: 100
Ref CA @32F: 690
20 Hour Capacity: 60
Terminal Type: Automotive
Length Inches: 9-9/16”
Width Inches: 6-7/8”
Height Inches: 7-1/2”
Weight Lbs.: 39
Type: AGM

Online Battery Store | Best Price Batteries, Chargers, Solar Chargers, Terminals, Cables and Accessories!

Battery Web | Best Prices On All Batteries & Chargers. Great Deals on Solar Panels and Battery Testers.

www.batteryweb.com

O'Reilly Auto Super Start Platinum Line: SSB | Part # 47PLT
•Group Size (BCI): 47
•AGM Valve-Regulated Battery Required
•Battery Located In Trunk
•Cold Cranking Amps (CCA): 600 CCA
•Cranking Amps (CA): 690 CA
•Reserve Capacity (min): 100 Minute
•Voltage (V): 12 Volt
•Length (In): 9-9/16 Inch
•Width (In): 6-7/8 Inch
•Height (In): 7-1/2 Inch
•Weight (Lbs): 39 Lbs.
•Terminal Type: Top Post
http://www.oreillyauto.com/site/c/s...ear=2011&make=Chevrolet&model=Volt&vi=5175792

Sears DieHard Gold AGM Automotive Battery - Group Size EP-47
Item # 02850747000P Model # 50747
Dimensions:
Item Weight (lbs.): 39
Length (in.): 9.625”
Width (in.): 6.875”
Height (in.): 7.5”
Group Size: 47
Power Ratings:
Cold Cranking Amps (CCA at 0 deg.F): 600
Reserve Capacity (RC): 100

German supplier Panther AGM 60 - 12 V / 60 Ah - 550 A/EN
http://www.batterie-industrie-germany.de/batterien/auto/big/big-agm-60-12-v-60-ah-550-a-en/a-1004/


Related threads:
https://gm-volt.com/forum/showthread.php?92913-can-you-put-another-type-of-12-volt-battery-in-volt/
https://gm-volt.com/forum/showthread.php?11231-12V-battery-replaced
https://gm-volt.com/forum/showthrea...-12-volt-battery-with-the-one-chevy-recomends
https://gm-volt.com/forum/showthread.php?10171-What-chemistry-is-the-Volt-s-12-volt-battery/
https://gm-volt.com/forum/showthread.php?198202-Replacing-12V-Battery.-Which-one-should-I-buy

 

[Steverino]

Info from a later thread:

MY 15 OEM Part Number: 47P7YR
MY 16 OEM Part Number: 47P7YR [Gen 2]
MY 17 OEM Part Number: 47P7YR [Gen 2]
ACDelcoPart Number: EVLN2
GMPart Number: 88865475
CCA (Service): 630
Battery*Type: AGM

----

#15-06-03-002F: Original Equipment Batteries Part Number and*ACDelcoReplacement*Battery*Approved Warranty Part Numbers – (Apr 6, 2017)

Title: DIY: 2016-2019 CHEVY VOLT -12 Volt AGM Battery Replacement!

 

[Raymondjram]

Wow! So many steps to replace an obsolete lead acid 12 VDC battery in a Chevy Volt! My 2009 Chevy Equinox battery is much easier to reach and remove because I have done it once.

I would pay GM the extra money to have a newer lithium-ion based 12 VDC battery factory installed in the trunk instead of the lead-acid one, and avoid all this work which will cost more time (as a DIYer) or cost money (to a layperson) to replace every certain amount of years.

 

[viking79]

Lead Acid is NOT obsolete tech. It deals with the cold far better than Li-ion and far superior to accepting an overcharge. Li-ion catches fire and burns if you overcharge it. They also have very high current capacity, and a small car battery can easily deliver 600 amps or something for a start even when very cold. Granted, the Volt doesn't need the cranking capacity, but the cold resistance is nice and since the battery is always kept fully charged (a bad situation for Li-ion) an AGM battery is perfect for the situation (and superior than Li-ion for the intended purpose).

Changing the battery is easy and probably necessary after 4 or 5 years with the Volt. A lithium based battery likely won't work as well in cold weather. It would be fine in Puerto Rico, but on a cold day in MN or AK it wouldn't start the car.

Sorry, several edits.

 

[MrEnergyCzar]

I paid my dealer in CT $275 total to replace my 2012 battery (after 5 years). Just getting the battery on your own will cost that much.

 

[Steverino]

Wow! So many steps to replace an obsolete lead acid 12 VDC battery in a Chevy Volt!

I could make picking your nose a 12 step process as well. I could also condense the Volt battery replacement into 4 steps. But you are correct, this is not an Equinox.

Your thought on replacing the AGM with a Li battery is also addressed above.

I paid my dealer in CT $275 total to replace my 2012 battery (after 5 years). Just getting the battery on your own will cost that much.

Then you are buying batteries at the wrong place, MrEnergyCzar. Check out the links for prices. You are paying about $100 more than the cost of the battery for the 15-20 minutes it will take to install it. Nothing wrong with helping out the dealer, but I'd rather pay myself that $200-$400/hour labor rate. Add the cost of taxes you paid to earn your $100 and the savings is more like $260-$520/hour.

 

[hellsop]

Then you are buying batteries at the wrong place, MrEnergyCzar. Check out the links for prices. You are paying about $100 more than the cost of the battery for the 15-20 minutes it will take to install it. Nothing wrong with helping out the dealer, but I'd rather pay myself that $200-$400/hour labor rate. Add the cost of taxes you paid to earn your $100 and the savings is more like $260-$520/hour.

FWIW, Sears normal charge to install a car battery is ten bucks. $200 should get you the battery, installation, tax, a case of heartburn from the lousy coffee, and (in most places) some change back to buy antacid with.

 

[Aus1]

For those who do wish to test the 12Vbattery (Has to be disconnected from Cars wiring as A/C ripple current is used by AGM testers)
One suggestion is the affordable AGM battery tester: QUICKLYNKS BAT101 after specifying CCA & AGM Flat plate type.
Less than 80% maybe time to order a New one ;-) I wonder why with all the electronic alternator smarts it is not able to estimate @ suggest a 12V battery replacement in time on the info console? Maybe a 12 V batteries length of life is random and unpredictable.

In the USA EVLN2 / GM 88864595
Specifications EREV BCI Group 47 Starting Battery Part Number: EVLN2 Product Notes: EREV Battery
All; BCI 47, minimum vehicle Reqment: CCA 630/RC 115; OE replacement; Hybrid; Battery is vented to outside of vehicle; Use vent tube 20908491; AGM Valve Regulated Lead Acid (VRLA) is Reqd
Per Vehicle: 1; Years: 2013-2013

Australia AC-Delco # S56090AGM
GM Part # 19314490
Capacity AH 60
Reserve Capacity 100
CCA 680
Terminal STD
Polarity/ Layout 0
Length 241mm
Width 174mm
Max Height 189mm
Bottom Hold-Downs B3

For some strange reason The Australian version is a different part number locally for us at both AC-Delco Australia and GM Holden.
Note the slight differences in CCA and RC values, however outside physically they are the same.
Different source of supply?

 

[hellsop]

For those who do wish to test the 12Vbattery (Has to be disconnected from Cars wiring as A/C ripple current is used by AGM testers)
One suggestion is the affordable AGM battery tester: QUICKLYNKS BAT101 after specifying CCA & AGM Flat plate type.
Less than 80% maybe time to order a New one ;-) I wonder why with all the electronic alternator smarts it is not able to estimate @ suggest a 12V battery replacement in time on the info console? Maybe a 12 V batteries length of life is random and unpredictable.

In the USA EVLN2 / GM 88864595
Specifications EREV BCI Group 47 Starting Battery Part Number: EVLN2 Product Notes: EREV Battery
All; BCI 47, minimum vehicle Reqment: CCA 630/RC 115; OE replacement; Hybrid; Battery is vented to outside of vehicle; Use vent tube 20908491; AGM Valve Regulated Lead Acid (VRLA) is Reqd
Per Vehicle: 1; Years: 2013-2013

Australia AC-Delco # S56090AGM
GM Part # 19314490
Capacity AH 60
Reserve Capacity 100
CCA 680
Terminal STD
Polarity/ Layout 0
Length 241mm
Width 174mm
Max Height 189mm
Bottom Hold-Downs B3

For some strange reason The Australian version is a different part number locally for us at both AC-Delco Australia and GM Holden.
Note the slight differences in CCA and RC values, however outside physically they are the same.
Different source of supply?

The only result most users (that is Volt owners) would care about for testing the 12v is "good" vs "bad". And the real PROBLEM is that we don't have a measure for "good" vs "bad" out here. We know what "bad" looks like -- computer boot up out of order, or fail to boot correctly at all, reference voltages are taken at the wrong points of the bootup and making readings taken from various sensors therefore wrong. This is going to be caused by some lack of power, but it could be voltage sagging too low, not enough current being supplied or (probably) both. But exactly how the battery fails to make that craziness happen, and at what POINT that failure happens hasn't been determined.

We do know that the tests for OTHER cars don't work work well. Those tests measure the "fully-charged" voltage of the battery with no load on it (usually saying 12.6 v is good, but 12.2 is bad), or they measure with TREMENDOUS load (that is a starter motor engaged, cranking an engine) and say that if the battery can keep it above 10.5 v, it's fine. What the Volt seems to need is something near/above 12v at moderate load (50-75 amps or so, not the 200+ that the starter motor wants) for up to about 20-30 seconds. That is, it's lighter load than normally tested but much higher cutoff voltage to read bad.

Now, it would be POSSIBLE to have put some kind of measure on the output voltage during start and take what voltage was actually KNOWN to cause problems, add a little bit and say "If the voltage drops below this at any point between button-push and READY light for more than 2 starts in a row or more than 3 in 10 or whatever, set a code and a check-engine light that says "replace 12v battery". But A) that would have had to happen during the design phase -- it's gonna be really difficult to add later, B) we don't even know what that threshold of "too low" voltage is, and it's Very Very complicated to determine by engineering instead of empirically by noting when strange things happen during/after boot, and C) the first thing most people are going to do is have one of these other tests performed, the battery declared to be in fine shape and that wasn't a problem, and customers mad that this obviously bogus code keeps showing up, all the way up until the car strands them someplace. At which point, maybe they take it seriously, and maybe not; we've all seen people come here with a story, have "replace your 12v" recommended, and lo, that's what solves the problem after a few go-arounds and trying other things.

 

[somms]

What the Volt seems to need is something near/above 12v at moderate load (50-75 amps or so, not the 200+ that the starter motor wants) for up to about 20-30 seconds.

Small & Cheap lithium-ion replacement for the 12V AGM battery

FWIW: After the lithium-ion jump pack I had installed in lieu of the normal AGM voltage dropped >10VDC, I could no longer successfully turn ON my Gen1 as detailed in the thread linked above!

 

[CCIE]

I paid my dealer in CT $275 total to replace my 2012 battery (after 5 years). Just getting the battery on your own will cost that much.

I bought the proper AC Delco EVLN2 Battery for my Volt from an AC Delco parts supplier for $135 + $12 core charge. Also in CT. It takes about 15 minutes to change the battery, assuming you have a socket set. Worth the savings to me.

Anyone with a 12V battery that's over 4 years old should consider proactively replacing it. These cars start doing weird things when the batteries get weak.

 

[Steverino]

Anyone with a 12V battery that's over 4 years old should consider proactively replacing it. These cars start doing weird things when the batteries get weak.

My battery is at 6 years. Everything fine so far. Consider me the control for the experiment.

 

[CCIE]

My battery is at 6 years. Everything fine so far. Consider me the control for the experiment.

I would expect AGM batteries to last 10 years. So, hopefully the people complaining about battery failures at 4-5 years (including myself) are the exception.


I do wonder if the low load that the Volt puts on the 12V battery is somehow detrimental to it. I would think that powering the starter on an ICE vehicle would be much harder on a 12V battery. But, the opposite seems true. I easily got 5-6 years from the OEM battery in every ICE car I've owned. My Volt started acting weird and not initializing around 4.5 years old. Tried a 12V battery disconnect to reset all computers, but ended up having to change the 12V battery to fix the issue.

 

[canehdian]

I suspect it's more to do with the usage patterns of the drivers. If you don't drive long enough the 12V isn't getting enough of a top up.
It was at least enough of an issue such that GM added a standby 12V maintenance mode to 2013+ (2014+?) cars to keep the 12V in good shape.
If you have an 11-12 and only drive it 5 mins to work and back and charge for 1/2h each night, it's probably not getting fully topped off if it's only charging 12V when on or actively charging.

 

[CCIE]

I suspect it's more to do with the usage patterns of the drivers. If you don't drive long enough the 12V isn't getting enough of a top up.
It was at least enough of an issue such that GM added a standby 12V maintenance mode to 2013+ (2014+?) cars to keep the 12V in good shape.
If you have an 11-12 and only drive it 5 mins to work and back and charge for 1/2h each night, it's probably not getting fully topped off if it's only charging 12V when on or actively charging.

I drive 30 miles each way to work everyday. So, I don't think lack of use was the issue for mine.

Maybe the AGM batteries in ICE vehicles get flaky too, but the computers are less sensitive for some reason?

 

[Aus1]

My Battery 12V Aux battery age = 4Years and 10 months since car was produced.
Battery reads from Good Recharge to Good Battery. 51% to 98%

I agree, usage patterns are important.... I drive relatively short distances,
When on holidays I put the car to sleep in transport mode so 12V battery is doing nothing but resting.
We don't have real frozen cold here ... ironically very cold is great for preserving battery life (Hot weather temperature is not)
But since it's in the boot and located bottom, I do not see Australian heat in summer having any affect on life.

My tester arrived today -
Did the out of car test - battery both leads disconnected as I didn't wan't to risk a/c ripples going through the Volt.
Set up for AGM Matt at 600CA which it says on the battery and also tested it on SAE 600CA as the battery is rated SAE.
The only difference is the calculated CCA as measured are different.
It read 51% charge, 12.31Volts, 4.83 mOhm Internal resistance, GOOD RECHARGE,

So I charged with my smart AGM charger set on small battery = 60 AH
It finished relatively quickly charging (<20mins) so suspect it only added an additional surface charge, before it went to absorption (maintenance mode) vs the electronic alternator in the Volt.

Charging was around 13.54V and finished with battery at 12.69V
Tested again in AGM Matt SAE 600CA
It read 98% charge, 12.6V, 4.73 mOhm Internal resistance, GOOD BATTERY.

Even though it's only a small 60AH battery, the Volts 12V battery should last a very time.

Link to photos Below.

https://goo.gl/photos/98igwHcXzQ2Zbe6L8

 

[hellsop]

I would expect AGM batteries to last 10 years. So, hopefully the people complaining about battery failures at 4-5 years (including myself) are the exception.


I do wonder if the low load that the Volt puts on the 12V battery is somehow detrimental to it. I would think that powering the starter on an ICE vehicle would be much harder on a 12V battery. But, the opposite seems true. I easily got 5-6 years from the OEM battery in every ICE car I've owned. My Volt started acting weird and not initializing around 4.5 years old. Tried a 12V battery disconnect to reset all computers, but ended up having to change the 12V battery to fix the issue.

From a not-engineer perspective, the demands a Volt puts on a battery are VERY DIFFERENT from the usual profile of use for a starting battery, and I also suspect that they're much more critical than "make a little motor turn a big engine over a couple of times and hope it goes by itself." Essentially you're starting a flock of computers that all have to come up within a certain window of time in relation to each other, or they start throwing errors around. That's a tricky job even in a data center with highly conditioned power. Trying it do it off a single battery over a 150F range of temperatures would be INSANE in that context, but we're expecting the car to do it every time.

By the same token, I expect that the nearly universal set of "battery testing" is all pointed at the same "little motor turns big engine a few times" demands, and I expect also that the same battery that isn't good for a Volt may well have years of "dumb iron" starter life left to it.

 

[hellsop]

I suspect it's more to do with the usage patterns of the drivers. If you don't drive long enough the 12V isn't getting enough of a top up.
It was at least enough of an issue such that GM added a standby 12V maintenance mode to 2013+ (2014+?) cars to keep the 12V in good shape.
If you have an 11-12 and only drive it 5 mins to work and back and charge for 1/2h each night, it's probably not getting fully topped off if it's only charging 12V when on or actively charging.

I don't believe this for a second. The 12v gets charge not only when the car runs, but also when the car charges, even back to the 2011. Even if you only drive a mile, the 12v is going to get 15 minutes of charging when you get home.

Plus, the amount of power actually drawn is much smaller to boot a bunch of computers. It should take rather longer to recharge from 30 seconds of starter-motor turning a big-block. 1 kw vs 3-5kw for the same amount of time.

 

[canehdian]

I don't believe this for a second. The 12v gets charge not only when the car runs, but also when the car charges, even back to the 2011. Even if you only drive a mile, the 12v is going to get 15 minutes of charging when you get home.

Plus, the amount of power actually drawn is much smaller to boot a bunch of computers. It should take rather longer to recharge from 30 seconds of starter-motor turning a big-block. 1 kw vs 3-5kw for the same amount of time.

The fact remains that GM added a 12V maintenance charge routine to later models - so it was necessary. Maybe not for every situation, but they felt it was enough of a problem to actually develop and implement a separate charging routine.

 

[hellsop]

The fact remains that GM added a 12V maintenance charge routine to later models - so it was necessary. Maybe not for every situation, but they felt it was enough of a problem to actually develop and implement a separate charging routine.

Yeah, and that helps when the car is plugged in and doesn't turn on for weeks. The case under discussion is "short, presumably frequent, trips". Unless you only go to work once a month, you lucky dog.