Battery gauge too low???

All of the previous GM's I have owned used to have the battery gauge indicator past the middle (14) but with the new Denali I have noticed that it is more on the lower side than it is on the higher side. Anyone else seen this with any Tahoe or Yukon/Denali? It doesn't seem like my lights are dimmer than normal or my wipers operate slowly or anything, but i'm curious as to why the gauge is so low. I'm not running aftermarket in the car either. Pic attached. All feedback is appreciated.

This is purely a guess, but I assume it is because of the high output alternator. My theory is that because the alternator puts out so much. The alternator doesn't need to max out the voltage to charge the battery back to full and still supply enough power to the rest of the vehicle.

The owners manual for my 07 Yukon XL says that the guage will fluctuate both high and low. As was previously mentioned, I think the high amperage alternator (160 amps) charges with bursts of power. When towing my travel trailer in rain for four hours last week, I noticed it stayed on the high side more because of the lights being on. Dean

Yea, I have noticed my 07 denali likes to stay on the high side of the line!!

The alternators on the GMT-900S basically shut down when the battery doesn't need charging to reduce the load on the engine and increase mpg. :thumbsup:

73shark,
Could you please explain that a bit more?
I just bought a 2005 Tahoe, and have noticed that the volt gauge is sometimes below the 13v mark. Shut off the engine, start again, and it goes to over 14 slowly.
Never seen this before. Traded in a 2000 Silverado, and it always ran over 14, unless the battery was going bad!:confused2:
Charles

Old Goat said:

73shark,
Could you please explain that a bit more?
I just bought a 2005 Tahoe, and have noticed that the volt gauge is sometimes below the 13v mark. Shut off the engine, start again, and it goes to over 14 slowly.
Never seen this before. Traded in a 2000 Silverado, and it always ran over 14, unless the battery was going bad!:confused2:
Charles

Click to expand...

my 06 yukon xl and 08 sierra denali run right at 14 and never a volt higher or lower, except for one time when i turned on both ac's at the same time it surged my lights dimmed for like a tenth of a second and it dropped a volt for a tenth of a second and then every thing was fine, now it does not even do that, but i have installed a 200amp high preformance alternator in it now plus a yellow top battery, but even before i did all that it did not flucuate. and stayed a stedy 14v, i have not modified my denali, and its stedy.

The Alternator is deactivated when not needed to reduce the parasitic lose of power. Any time the charge is not needed it will shut off. You will notice the guage changing now that we brought this to your attention. Unfortunately the first time you noticed it was off.

So, you are saying that this is NORMAL?
Gonna take some getting used to.
Charles

Not sure the 2005s had the deactivation feature. You might want to check with your service dept. If it doesn't have it, then might want to get the electrical system checked.

yup

ya it gets under 14 on my 97 tahoe... i dont know why but i think im gonna go and find out

My 08 fluctuates every now & then too. Havent had any issues with charging system.

Document ID# 2000522
2007 GMC Truck Yukon XL Denali


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Subject: Voltmeter Gage Fluctuation - keywords battery charge camper cluster electrical excessive fluctuation gage gauge generator intermittent ipc lamp light low operation trailer towing tow volt voltage wire #PIT3331D - (07/27/2007)



Models: 2005-2008 Cadillac Escalade, ESV, EXT

2005-2008 Chevrolet Avalanche, Silverado, Silverado Classic, Suburban, Tahoe

2005-2008 GMC Sierra, Sierra Classic, Yukon, Yukon XL, Yukon Denali, Yukon Denali XL

with Regulated Voltage Control (RVC)




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The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
Some customers may comment that their volt gauge is fluctuating between 12 and 14 volts on their full size pickup / utility vehicle. Starting with the 2005 model year, light duty full size pickups and utilities, are equipped with a new Regulated Voltage Control (RVC) system. This system reduces the targeted output voltage to 12.6-13.1 volts when in "Fuel Economy Mode" to improve fuel economy. The alternator may exit "Fuel Economy Mode" if additional voltage is required. This will cause the voltmeter to fluctuate between 12 and 14 volts as opposed to non-regulated systems which usually maintain a more consistent reading of 14 volts. This fluctuation with the RVC system is normal system operation and NO repairs should be attempted. See picture below for the normal operating range of the voltage gauge. Review PIT4426 if having concerns with keeping a camper/trailer battery properly charged.





Recommendation/Instructions:
No repairs should be attempted and please reference the owners manual under Section 3 (Instrument Panel) "Voltmeter Gage" for more information.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.



GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION


© Copyright General Motors Corporation. All Rights Reserved.


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Document ID# 2000522
2007 GMC Truck Yukon XL Denali

THANK YOU ever so much, brodg.
Now I'll just have to get used to it! Old habits are hard to break!
Charles

volts gauge low

I have a 2004 Tahoe LT 45000 miles NOT a problem with it til recently..... My volts gauge dips down to 10-12 usually at 14+ checked battery its fine diconnected + side of battery truck stayed running altenator good...... Any1 seen or heard of this????? AJ

personally i would not worry about it until the lights start dimming! actually the guys in the 2000-2006 section might have more knowledge and might be able to answer your question a lot better.

Just a footnote - from my experience with both an 05 Suburban and Avalanche: that smart charging system (forget the name) balances fuel economy as well as battery life amongst other things. There are a number of different modes . . . . long story short, the delco battery in these trucks is crap and starts degrading after two years so you will start to see more frequent and extreme swings as time goes on.

Since that annoyed me, and since the low voltage was causing fuses to blow when I plugged in my laptop through an inverter, I put Optima red tops in both trucks. Problem solved, fewer swings and higher voltage.

PS Check posts from a guy named sperry on CAFNA (avy fan club): http://www.chevyavalanchefanclub.com

Also, I believe this applies to 2005 and newer trucks, not the older ones.