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Discussion Starter #1
For those that haven't had their 12 Volt battery fail, it is coming. They seem to last about 4 years.

My early model 2012 car wouldn't run this afternoon when my wife tried to start it, said "Initializing"... and took forever to boot. Behavior was very strange and didn't seem like a dead battery, various system error messages, "service high voltage", ABS not available, etc. Whatever system failed to boot. Wouldn't even turn off. Strange as heck.

Because of the great help here I figured this was the 12 Volt, and some battery features like horn the horn and rear trunk release didn't work.

Thankfully my local Advance had a replacement, expensive battery, but easy repair. Car starts great. Don't get yourself stranded, know the signs of a failing battery.
 

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Good to know, thanks!;)



This is one of the reasons I recently added an OLED mini DC Voltmeter to my Gen1 as the original AGM battery will soon be > 4 yrs old and hopefully this meter may show when this battery is about to fail.
 

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Good to know, thanks!;)

This is one of the reasons I recently added an OLED mini DC Voltmeter to my Gen1 as the original AGM battery will soon be > 4 yrs old and hopefully this meter may show when this battery is about to fail.
Yes, your setup is ideal and well done. And I suggest all you 2011-2013 Volt owners who still have the original 12 VDC battery to do the same. Get a plug-in DC meter and watch it every day. Read the original post to learn how he did it and how to determine when that battery needs to be replace before your Volt leaves you stranded and embarassed against ICE drivers who pass you by.
 

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I was thinking, if my TV satellite receiver can tell me when the remote batteries are getting low and need to be changed, why can't my Volt do the same? The TV remote still functions normally, but the receiver can sense that the transmitted signals are getting low.

The Volt has systems that are active even though the car is "off", or not being charged. So why can't the Volt measure the idle 12v battery and give you a message that battery may need some attention?

BTW, my OE 12v battery is still humping along in the Arizona heat after 5.5 years. Something caused it to go flat on me about 18 months in, but a good external charger brought it to life and it has been no issues since (still knocking on wood).

VIN # B0985
 

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I'm still running my original 12 volt battery in my 2011 Volt. I did buy two compact lithium ion battery jump starters to keep in both of our cars, just in case. I can tell you it worked great when we went on vacation in our old 2006 RAV4 and left the dome light on for a week. 12 volt battery was dead, hooked up the lithium ion jump starter, and the engine started right up.

Highly recommended, and easily slides under the passenger seat for storage.
 

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I'm still running my original 12 volt battery in my 2011 Volt. I did buy two compact lithium ion battery jump starters to keep in both of our cars, just in case. I can tell you it worked great when we went on vacation in our old 2006 RAV4 and left the dome light on for a week. 12 volt battery was dead, hooked up the lithium ion jump starter, and the engine started right up.

Highly recommended, and easily slides under the passenger seat for storage.
Same here with the jump starter, however I've not had an opportunity to use it.

VIN # B0985
 

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The Volt has systems that are active even though the car is "off", or not being charged. So why can't the Volt measure the idle 12v battery and give you a message that battery may need some attention?
Essentially because you can't usefully test an idle battery for actual capacity. You need to drain it at a fixed current rate and see how much sooner it reaches a cutoff voltage than it should, and doing that at a rate that won't damage the battery takes hours. How long would drivers put up with "Do not disconnect charging cord. Battery test in progress"?
 

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Discussion Starter #8 (Edited)
Exactly, low voltage can be a clue, but might not work every time. The bad battery in my motorcycle showed fine voltage with no load, but as soon as you put a heavy load on it the voltage dropped to zero across the battery. Internal short or something.

Watching a Volt meter while the car is initializing might give a clue if the Voltage collapses as it starts drawing current. I didn't try this time, just knew it was a shot battery. I probably should have tried jumping it to make sure it wasn't a one time thing (like pretend the car didn't turn off all they way for some reason and drained the battery), but it was 4.5 years old and I know that is about how long they seem to last in the Volt.

Somms, not a bad idea to have a Volt meter in there, seems like it should be built in given the tech nature of the car ;) I almost wish GM would put a custom screen on the display that we could add any OBD II information we wanted, graphs and such, would definitely appeal to tech people.
 

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The facts are SO MANY things that can cause the conditions you describe. (extended "initializing" with various "service" messages)
Certainly, you may have lucked out but unfortunately more often than not the real root cause will raise it's ugly head at some point (In my experience often at the point it switches to extended range mode) In this case it would have been good to have all the DTCs and fail records recorded.
While some may find it "interesting" constant monitoring the 12V is a waste of time IMO as by the time you observe an abnormal value it will be too late.

WOT
 

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The problem now is that if it wasn't simply a low battery, as WOT suggests, by disconnecting you likely cleared any stored codes.
I would always scan for and record codes before going through with a battery change, just in case.
 

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Discussion Starter #11
No, battery was obviously weak, dim heaflights and sickly sounding horn. It was shot. Unhooking and rehooking and keeping remotes away for 10 mins didn't help.
 

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Discussion Starter #12
In this case, every time I tried to start the car it was different systems throwing errors, and it got worse as the battery depleted. Whatever system failed to boot caused trouble, wasn't the same one on each attempt. As mentioned above, the horn and lights were telltale signs of a weak battery. Sure it was a bit of a gamble, but figured my odds were 20:1 or so it was a bad battery, and definitely seems it was.
 

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Essentially because you can't usefully test an idle battery for actual capacity. You need to drain it at a fixed current rate and see how much sooner it reaches a cutoff voltage than it should, and doing that at a rate that won't damage the battery takes hours. How long would drivers put up with "Do not disconnect charging cord. Battery test in progress"?
Maybe the Volt could isolate the 12v battery on startup while the DC-DC is providing power to the 12v bus, and evaluate it's state of "goodness" without affecting the operation of the Volt. If found to be good, then touch it up and put it on line. If found to be weak, then a message could be posted. Not sure it would take hours - just my thinking.

VIN # B0985
 

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I replaced my 12v at four years. It seemed to be working fine but we use the Volt for hiking and returning to a dead car in the middle of nowhere wasn't that appealing. For ICEs you'd get some warnings but with EVs the first warning can be the car not starting or a ton of weird codes.

I have to agree with the OP that replacing the battery seemed like the logical first step. When you have so many codes it's either a major failure which a new 12v won't fix or it's a 12v problem or it's a 12v problem and something else. At four years he's due to replace the 12v anyway, and if there are other issues they will reveal themselves in short order. Can't see the downside of the replacement.
 

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Maybe the Volt could isolate the 12v battery on startup while the DC-DC is providing power to the 12v bus, and evaluate it's state of "goodness" without affecting the operation of the Volt. If found to be good, then touch it up and put it on line. If found to be weak, then a message could be posted. Not sure it would take hours - just my thinking.
Caveat: I am not an electrical engineer. I just read a lot about this stuff for other purposes.

There's three common ways to test a battery that doesn't get into chemistry specifics like measuring acid concentration.

1) Loaded Voltage test: How much oomph is there when a load is applied. It's easy and quick and available basically any time but that only tells you about 2.5 things: That the battery isn't internally shorted, that the internal resistance isn't too high, and the half thing is that you learn whether the thing is discharge enough to be damaging the battery, since you know the chemistry. "I'm still above 12.2 V, so I can discharge this a little more, but I have to stop at 12.1" or something. How much use happens in that last 0.1 V can only be guessed at (a la guessometer) by historical usage and trusting that conditions (temperature, current draw, condition of the battery) haven't changed much since last time.

2) Resonance test: Basically use a solid state switch to short the battery dozens or hundreds of times a second, applying a charge the other half the time, and measure the current that comes out during the short. This gives you a measure of how many amps the battery could discharge if it were called upon to, for a short period of time. This is how (for example) normal ICE starting batteries get measured for how many "Cold cranking amps" they have left, and if it's too far from the rating, that's an indication that it's time to replace the battery.

3) Constant Discharge ("C-rate") test: Attach battery to a special testing device that automatically varies resistance and measures voltage and current flow, and (armed with the proper cutoff voltage from knowing the chemistry and what the expected AH of the battery is) measures how long it actually takes to discharge down to the cutoff at a set number of amps of flow. This kind of testing can be really hard on the battery's overall life, and how hard it is depends entirely on how fast you do it. Run a C/20 test that takes 20 hours plus however long it takes to charge the battery again, and you'll use up about one discharge cycle from the life of the battery. (Hopefully, it takes 20 hours, anyway. What you're testing is the amp-hour capacity of the battery after all, and if the 20 hour test reaches the cutoff voltage in only 16 hours, that means your 10 AH battery only actually has 8 AH of capacity and trying to take more than 8 AH will damage it further. Do that more than a couple of time and it's new battery time Right Now.) Run a 5C test (that can be done in 12 minutes, plus charge time), and you'll have burned probably dozens of charge cycles from the life of that battery. You'll get different capacity results from different C-rates too, so you need to choose one that meets the expected actual use of the battery. The 12V AGM in the Volt spends the vast, vast majority of its duty powering OnSta, the alarm system, the keyfob radio, etc, so the actual draw from the thing is mostly very very very slow, and a C/20 test is about as close as could possibly be practical to try. The thing about the C-rate test, though, is that you don't get to access that battery while it's running, so you need some other sort of power available. HV pack is there, but the state of that can't be depended upon if the car is driven. The generator is there, but there's circumstances where we might not want the generator firing up (such as an enclosed garage without provisions for dealing with exhaust). Wall power is there, but if we're plugged in then we can't drive. Or at least, would need an entirely different from normal starting sequence like "get in, start car, get out, unplug, close charge door, get back in" and something even possibly more complicated for shutting down. Granted, all that could be engineered away to put in a c-rate testing system onboard for the 12V, but at some point, that gets to be a lot of engineering and parts complexity for a thing that can also be addressed by "watch for funny behavior, or just change the 12V when it gets 3-4 years old."
 

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I have one of the voltmeters shown in the attachment. The problem is that the outlet is switched, and will probably never show you a bad battery. If the car has an issue and can't start, the outlet will never turn on. If the battery starts the car, the HV dc-dc kicks in and drives the 12V bus up to do some re-charging. When you turn OFF the car, there is Retained Accessory Power, that keeps the outlets on for a few minutes, so you'll see the battery voltage then decay, but that's always after a successful start.
12v_auto_voltmeter.jpg Auto-plug-voltmeter.jpg

I added a standard 12V barrel jack near the left rear fuse panel, so I can plug in and monitor the battery easier. I can plug in a meter, solar charge controller, or a trickle charger. I see the battery rest state normally about 12.2 to 12.4V. Anything higher is due to the car being on and the DC-DC contributing to the voltage.

Jack-charge-controller_20160704.jpg
Note that the little Watts-Up meter isn't really suitable for automotive use, the LCD blacks out in the summer heat!
 

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@hellsop, btw, nice write up above!
 

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I have one of the voltmeters shown in the attachment. The problem is that the outlet is switched, and will probably never show you a bad battery. If the car has an issue and can't start, the outlet will never turn on. If the battery starts the car, the HV dc-dc kicks in and drives the 12V bus up to do some re-charging. When you turn OFF the car, there is Retained Accessory Power, that keeps the outlets on for a few minutes, so you'll see the battery voltage then decay, but that's always after a successful start.
Solved the AGM + APM in parallel reading issue by wiring in a 3Pin SPDT ON/OFF/ON switch to be able to read B+ 12V AGM w/o turning the vehicle ON as well as this switched 14V APM power with the vehicle ON. You could also push and hold the ON button w/o pressing the brake pedal will engage this retained accessory outlet(s) without powering up the APM and show true 12V AGM battery voltage. Again, this would only work if the 12V AGM has enough juice to engage this relay in the first place!;)
 

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Caveat: I am not an electrical engineer. I just read a lot about this stuff for other purposes.

There's three common ways to test a battery that doesn't get into chemistry specifics like measuring acid concentration.
you missed one (and notably the method used most often these days in automotive service) -Conductance Testing.
http://www.stationary-power.com/support--reference-values/frequently-asked-questions/
Specifically GM dealers have been a Midtronics GR-8 conductance testing tool for the last 8 years.
http://www.midtronics.com/shop/products-1/battery-chargers-and-maintenance-products/diagnostic-chargers/gr-series/midtronics-gr8-series-diagnostic-battery-chargers
They have proven incredibly accurate and can even detect various issues before an actual DOA takes place
When you dealer states they tested your battery this is what they use

WopOnTour
 
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