# Need advice - Battery voltage fluctuating from 12.0V to 14.0V



## djk-crzeco (May 9, 2018)

Hello everyone!

I purchased a 2011 Chevy Cruze Eco a couple weeks ago and loving it so far. Did a lot of research before purchasing the car to really know that this is the car that fits me best. It's economical, it looks sporty, equipped with a turbo, and not a **** Honda  Mechanically everything is good, and I even took it to an O'Reilly's during the test drive to get the system scanned with the OBD and no codes, not even P1000 which is evidence for codes being erased and in calibration phase.

Aside from the engine turning over abruptly during warm starts, no major issues to speak of. However, I just noticed on my commute home that the battery voltage weirdly fluctuates from 12.0V to 14.0V with no evident correlation to pedal input, engine revolutions, idle, etc. It seems to be acting on a mind of its own.

During the pre-purchase inspection, I did identify and mention corrosion on the battery terminals, and maybe that's causing a large range of battery voltage? Could anyone give input if they've experienced this before? I know I have to clean off the corrosion soon to better diagnose this issue, but if you have any pointers, I would appreciate it.

Thanks!


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## mikestony (Jan 17, 2013)

Well, you are on the right track with the corrosion being suspect! Clean both terminals and battery posts, reconnect and monitor the voltage.
Simplest thing to do and start from there.

Also when you take off the cables, inspect them as best as you can for corrosion.


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## snowwy66 (Nov 5, 2017)

It's the new gas saving technology. Your alternator is just fine.


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## ChevyGuy (Dec 13, 2014)

djk-crzeco said:


> the battery voltage weirdly fluctuates from 12.0V to 14.0V with no evident correlation to pedal input, engine revolutions, idle, etc. It seems to be acting on a mind of its own.


It's completely normal for voltage to fluctuate based on engine load. If the car needs more power (such as during acceleration), it may dial back the charging voltage. If it has power to spare, it will take the opportunity to charge the battery. You might want to study it in that light. 

That said, bad battery ground cables are common. And any corrosion should also be addressed. 

Also, be on the lookout for any devices that connect directly to the battery. The car monitors battery current and incorrectly installed add-on devices might fool the system into cutting back the charging voltage.


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## djk-crzeco (May 9, 2018)

Thanks so much, everyone! Very good insight on this, and I won't have to worry too much. I will be sure to inspect and clean any corrosion spots on the battery terminals. Thanks again everyone.


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## mikestony (Jan 17, 2013)

I find it hard to understand why 12 volts would be ok for a charging voltage while the engine is running? Or am I misunderstanding some of the replies?


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## Rivergoer (Mar 30, 2017)

mikestony said:


> I find it hard to understand why 12 volts would be ok for a charging voltage while the engine is running? Or am I misunderstanding some of the replies?


This older post explains it pretty well http://www.cruzetalk.com/forum/17-o...uze-regulates-voltage-boost-fuel-economy.html

On the other hand, the suggestion to check/clean battery posts, cables, etc is a good one especially given the age of the vehicle.


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## boraz (Aug 29, 2013)

mikestony said:


> I find it hard to understand why 12 volts would be ok for a charging voltage while the engine is running? Or am I misunderstanding some of the replies?


its doing what its supposed to be doing/designed to do

100% normal


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## boraz (Aug 29, 2013)

my battery reads 11.5v on the DIC before i turn the key and starts perfect

and ranges from 11 something to 15 something while driving

its what it does

its not your fathers oldsmobile


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