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I have 2 '12 Cruze Eco's. Scrolling through the vehicle information screens after sitting overnight at 60F, one car shows 12.2V with the Key On Engine Off (KOEO). The other car shows 12.3V KOEO. Charts show this to mean the battery needs to be charged and is only at 60% charged. In these conditions, what is your KOEO voltage, how old is battery, and how warm is it there?

The car with 12.3V is a salvage title that I rebuilt a year ago with 30K miles. As with many salvage cars, it sat for a long time before it went to auction, and the battery was weak when I got it. The Sears charger that I used showed a yellow LED that never went away, but the battery cranked fine after charging and did OK on a load test. I chalked it up to a weak cell, and we have been using that battery for over a year and 10K miles without issue.

The 12.2V Eco has 80,000 miles, and we bought it new. The battery has never been dead in the time that we've owned it.
 

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Both appear to be borderline. How quick is the start when you crank the engine?
 

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Sup Gus .. what great question from a guy whom resurects the Dead .

That cruze I traded in would give a KOEO reading of 12.3 volts DC for 4 years of ownwership . no issues there what so ever . tough little Batteries I would Guess . I even ran an Amp 8 months a year with no ill affects to the Battery . I did notice a 15.2 and a 14.7 charging during the winter months but that could be contributed to running all of the electronics in zero degree weather ..
that was the 1 thing I was concerned about during the winter months here in chicago with it's low temps .
Is the OEM battery rated for 7 years or not ?
 

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Even after replacing my battery (down to 11.0V before crank), my Cruze sits at 12.3-12.5 with engine off (depending on outside temperature most of the time). These cars do have an alternator with a clutch that will stop charging when the engine is under load or battery doesn't need to be charged anymore - I think they just try to keep from charging away unnecessarily and keep it around an 80% level.

I would not be concerned unless you see it drop below 12V.
 

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Even after replacing my battery (down to 11.0V before crank), my Cruze sits at 12.3-12.5 with engine off (depending on outside temperature most of the time). These cars do have an alternator with a clutch that will stop charging when the engine is under load or battery doesn't need to be charged anymore - I think they just try to keep from charging away unnecessarily and keep it around an 80% level.

I would not be concerned unless you see it drop below 12V.
Thanks for the reply. I may load test them, and if they're ok, keep on rolling.
 

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Sup Gus .. what great question from a a guy whom reserects the Dead .

That cruze I traded in would give a KOEO reading of 12.3 volts DC for 4 years of ownwership . no issues there what so ever . tough little Batteries I would Guess . I even ran an Amp 8 months a year with no ill affects to the Battery . I did notice a 15.2 and a 14.7 charging during the winter months but that could be contributed to running all of the electronics in zero degree weather ..
that was the 1 thing I was concerned about during the winter months here in chicago with it's low temps .
is the OEM battery rated for 7 years or not ?
The battery is warrantied for 7 years as a replacement battery but I don't think it is as an OE battery. I'll load test the batteries, and if good, keep running them. Strangely, recently I've found dealers to be the cheapest place to buy batteries, but I don't think I'll need one.
 

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J, I don't think there's a clutch on the alternator. The BCM is programmed to charge the battery only in certain situations, I think it's all "logic" built in to the charging algorithms. The BCM monitors battery loads with the hall-effec sensor mounted to the front of the battery tray, the ring shaped thingy the battery ground cable passes through.

Gus, the Cruze is designed to limit battery charging in order to reduce fuel consumption. After a lengthy discussion with Scifi a few years ago, I discovered the Cruze actually has several operating charge modes, something completely foreign to me at the time. What I got out of that learning period was that the Cruze maintains lower battery charge levels than what most are used to seeing. This could be responsible for the somewhat low KOEO voltage you're seeing.
 

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J, I don't think there's a clutch on the alternator.
I'm not sure as one is needed. Just turn off the field on it and it's pretty free-rolling. Just the fan, bearings and rotational inertia. I don't think there's much drag to speak of until the field is turned on to crank out the juice.
 

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Well since my voltmeters have to be NTIS traceable, used one directly across the battery terminals. To read exactly 12.9 volts after removing the surface charge at 70*F. DIC in this thing always reads low, mine shows 11.7 volts.

On my boat and motorhome with analog meters was able to remove and calibrate these. But with the Cruze, don't know if its a voltage drop with copper losses, or if the firmware is screwed up. But just learned to see if it says 11.7 volts, this is normal.

With the engine running at 1,500 rpm, expect to read 14.5 V across the battery at room temperatures, does this, so perfectly fine.
 

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Well since my voltmeters have to be NTIS traceable, used one directly across the battery terminals. To read exactly 12.9 volts after removing the surface charge at 70*F. DIC in this thing always reads low, mine shows 11.7 volts.

On my boat and motorhome with analog meters was able to remove and calibrate these. But with the Cruze, don't know if its a voltage drop with copper losses, or if the firmware is screwed up. But just learned to see if it says 11.7 volts, this is normal.

With the engine running at 1,500 rpm, expect to read 14.5 V across the battery at room temperatures, does this, so perfectly fine.
11.7? Id be concerned. What's it say at the terminals with a voltmeter?
 

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Jblackburn I am beginning to think you need some rest .
After a charge Aesop is getting a 12.9 at the terminal .
 

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DIC in this thing always reads low, mine shows 11.7 volts.
You're the first to report a DIC reading of < 12V. You might want to poke around the BCM and see if you've got a voltage drop somewhere in your wiring.
 
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