# 2018 LT Sedan battery draining



## Yoyotinab (Dec 9, 2021)

Hey all! Thank you for reading this. I have a 18' Cruze LT purchase with 16k miles currently at 25k miles. I have replaced my alternator and battery but am still having issues. The batter is pulling about 12.3V on average and drops down to 11.9V usually this happens while I am driving straight and not using the gas as much during traffic. This issue has been going on for about two weeks which is why I replaced the alternator first and now I upgraded to the best batter for the car. Is anyone having this issue? How do I handle it. I am going to the dealership that sold it to me. My mechanic said it could be a wiring issue.


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## snowwy66 (Nov 5, 2017)

It's perfectly normal..
It's how the system was designed. To save fuel.

Get yourself some type of obd2 Bluetooth plug in and use torque app on your phone. Don't rely on the dash. You'll get a more perfect reading using an app.

Turn on your headlights and you should get 14v.


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## Johnny B (Jun 4, 2019)

All what Snowwy said is true.
That said, 11.9 V is a bit low (if its real), unless it is just from a transient. Our alternators have there outputs "commanded" to different levels for many reasons. The old days of a steady 14.4 VDC output are gone. Going back to Snowwy the DIC is not what you want to rely on for ANY parameter. Be aware that many displayed values aren't a direct reading, they are often programmed feel good numbers. OBD2 readers are super cheap. hint hint wink wink.


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## Yoyotinab (Dec 9, 2021)

snowwy66 said:


> It's perfectly normal..
> It's how the system was designed. To save fuel.
> 
> Get yourself some type of obd2 Bluetooth plug in and use torque app on your phone. Don't rely on the dash. You'll get a more perfect reading using an app.
> ...


The headlights are on Automatic. Every time I use them manually after I shut the car off they switch back to auto. I also didn't know what a OBD2 was and had to Google it lol I'm just nervous that it will die on me.


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## Yoyotinab (Dec 9, 2021)

Johnny B said:


> All what Snowwy said is true.
> That said, 11.9 V is a bit low (if its real), unless it is just from a transient. Our alternators have there outputs "commanded" to different levels for many reasons. The old days of a steady 14.4 VDC output are gone. Going back to Snowwy the DIC is not what you want to rely on for ANY parameter. Be aware that many displayed values aren't a direct reading, they are often programmed feel good numbers. OBD2 readers are super cheap. hint hint wink wink.



I get the battery tested and it's a few days old now and they always tell me to get off the road because it's so low. I'm just nervous. This is my first car and I got a slightly used car to prevent a ton of mechanical issues and I have done the opposite of what I wanted. I just want to prevent myself from killing it.


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## Blasirl (Mar 31, 2015)

Yoyotinab said:


> I get the battery tested and it's a few days old now and they always tell me to get off the road because it's so low. I'm just nervous. This is my first car and I got a slightly used car to prevent a ton of mechanical issues and I have done the opposite of what I wanted. I just want to prevent myself from killing it.


Welcome Aboard!

These posts are for the *Gen I*, but they still have some relevant info in them:

Don't forget to introduce yourself and your Cruze here.


*How-To: Installation of the Big 3 Cruze Kit*
Clean the Terminals
Cruze Battery Upgrade Options
Battery Tab
Both positive and negative _battery cables_ at the battery are torqued to *40 in-lbs*
The_ battery plate nuts_ are torqued to *106 in-lbs*
and the b_attery hold down_ arm is torqued to* 80 in-lbs*


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## 17Hatch6MT (Dec 28, 2015)

Is definitely suspicious that you're still having problems-- but are you? Has the car not started since you replace the alt and battery? Has a qualified mechanic told you something is wrong?

Turn the headlight switch all the way to the right to make the headlights turn on. I don't know what the DIC reads when you do that... haven't checked mine. I do know that when off the throttle & on engine braking, I can feel the car sometimes slow down 'faster'. I'm thinking this is the alternator being commanded to run.

My DIC also reads in the high 11s on a cold day before I start the car. Did that since Day 1. (May be related-Cold starts on a very cold day, say < 25F, usually get a 'Service Stabilitrak' message on the dic; I've learned to ignore that.) Car is now five years old and on its original battery & has never needed charging system service. Recently had it in for an oil change & coolant flush at the local mechanic. They also tested the battery (with what, I don't know), told me it was fine, told me these batteries usually go at least 7 years.


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## Yoyotinab (Dec 9, 2021)

17Hatch6MT said:


> Is definitely suspicious that you're still having problems-- but are you? Has the car not started since you replace the alt and battery? Has a qualified mechanic told you something is wrong?
> 
> Turn the headlight switch all the way to the right to make the headlights turn on. I don't know what the DIC reads when you do that... haven't checked mine. I do know that when off the throttle & on engine braking, I can feel the car sometimes slow down 'faster'. I'm thinking this is the alternator being commanded to run.
> 
> My DIC also reads in the high 11s on a cold day before I start the car. Did that since Day 1. (May be related-Cold starts on a very cold day, say < 25F, usually get a 'Service Stabilitrak' message on the dic; I've learned to ignore that.) Car is now five years old and on its original battery & has never needed charging system service. Recently had it in for an oil change & coolant flush at the local mechanic. They also tested the battery (with what, I don't know), told me it was fine, told me these batteries usually go at least 7 years.



I still have the same issues. Since shutting the lights off and manually controlling them the battery has started to recharge. My mechanic recommends having the Chevy dealership go wire for wire and seeing it there is a fault. I did notice my battery dropped to 11.8V last night while I was driving. But I just reved the engine while I was parked with the headlights on and it was able to recharge. I live in Miami so it is always hot. When I turn the car on it usually starts at 12.2V and stays there for a bit and droops and goes back up in V's. I know that part is normal. Tbh I think I just got a bad Cruze. The dealership wants up to $1000 and four days with my car to diagnose it. I personally don't have that hints why I am here lol


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## Yoyotinab (Dec 9, 2021)

Blasirl said:


> Welcome Aboard!
> 
> These posts are for the *Gen I*, but they still have some relevant info in them:
> 
> ...


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## 17Hatch6MT (Dec 28, 2015)

You had the new battery tested at a qualified shop after a few days of use, and they told you its charge status is low?

If the car has been starting normally, why worry? Dealerships are only too happy to take your money. How many recent GMs has your advising mechanic worked on-- Are they qualified to advise on this topic?


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## Yoyotinab (Dec 9, 2021)

17Hatch6MT said:


> If the car has been starting normally, why worry? Dealerships are only too happy to take your money. How many recent GMs has your advising mechanic worked on-- Are they qualified to advise on this topic?


Not sure. My current mechanic had the shop sold anyway so I need to find a new one. The problem isn't the car starting.... You should reread my original post again.... The problem is the battery drains while I drive it and has shut off on me. Thanks for the advice. 👍


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## 17Hatch6MT (Dec 28, 2015)

Didn't realize the car was stopping running. That definitely would be a problem.


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## Blasirl (Mar 31, 2015)

Yoyotinab said:


> Not sure. My current mechanic had the shop sold anyway so I need to find a new one. The problem isn't the car starting.... You should reread my original post again.... The problem is the battery drains while I drive it and has shut off on me. Thanks for the advice. 👍


I just thought of something else. Does the Gen II have the -forgot the name- Hall effect sensor that all grounds travel through to sum up all the current being used? If so make sure all grounds that should have been going through it still are. This is what the BCM (IIRC) uses to control the alternator output. This picture shows some that are not in there, but this is a Gen I.


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## Yoyotinab (Dec 9, 2021)

Blasirl said:


> I just thought of something else. Does the Gen II have the -forgot the name- Hal effect sensor that all grounds travel through to sum up all the current being used? If sdo make sure all grounds that should have been going through it still are. This is what the BCM (IIRC) uses to control the alternator output. This picture shows some that are not in there, but this is a Gen I.
> 
> View attachment 295189



They are replacing my ground wire. My alternator and battery have gone again


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## Blasirl (Mar 31, 2015)

Yoyotinab said:


> They are replacing my ground wire. My alternator and battery have gone again


Let us know what happens.


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