Voltage

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2007 Chevy Silverado Classic 5.3L 4x4
Voltage Gauge Fluctuates between 12.8-15.25 Check with a DMM and voltage to agree with the gauge. Dealer explained as a Regulated Voltage Control System, is this just a fancy
name for a voltage regulator? Two wires on alternator: large one goes to the battery, the other I assume goes to the volt gauge. So how would the computer control this as explained where it turns the alternator on and off as needed. Truck parked one day without use in temperature of 20*F, driven for one hour in daylight. Voltage stayed at 15.25v Voltages just seen to unstable and high. Tx, Mike
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Mike wrote:

I remember seeing the TSB starting around 05 or so. Basically they enable and disable the alternator to save a tiny bit of fuel. Kind of like your computer monitor going into power save mode. They will shut down charging and let the battery run the electronics for a while then enable charging for a while to re-charge the battery. Seems like a way to wear out the battery faster to me :)
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Mike wrote:

Excerpt from http://media.gm.com/us/gm/en/news/press_kits/07%20fs%20pickups/07_GMT%20FS%20Trucks_Powertrain.html
" Regulated voltage control
All new truck engine controls feature regulated voltage control (RVC), which uses GM-patented technology to optimize the alternators electrical load by reducing output voltage when the battery reaches an 80-percent state-of-charge. This helps extend the batterys life and bolsters fuel economy by reducing the engine load required to run the alternator.
With RVC, a sensor monitors the batterys state of charge and can trigger a reduction in voltage when appropriate. There is no reduction in voltage during the operation of the windshield wipers or headlamps. GMs RVC technology on the Chevy Silverado and GMC Sierra is integrated into the vehicles body control module rather than the previous separate module design which enhances overall operation and improves component durability. "
The small wire should be the control. The gauge would be tapped off the battery wiring so it would show if alt not charging the battery.
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So would this mean since my voltage stayed at 15.25v, 1 hour daylight driving, blower on speed 2, no other electrical load other than normal that there could be a problem with my battery? I would not think the battery discharged much in one day of non-use. My normal commutes are 2 times 15 minutes trips/day, mainly at night. Please forward any more details to educate me. Thank you for the article. Mike

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GM is starting to be like Ford now with better ideas that stink!! If they where seriuos about saving maybe .1 MPG at most this way they could serve in better by taking a few hundred pounds of weight out of it. THis has got to be one of the worst ideas I have heard. If nothig else your voltage should be stable all the time. I predict after a year or 2 or consumer complaints they will scrap the idea. ----------------- TheSnoMan.com
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Lately, some people have been claiming that you're here to help.
Where is the help in that post?
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On Mon, 05 Feb 2007 15:00:44 GMT, aarcuda69062

Avoid buying a 2007 model GM maybe? Do not get me wrong I like GM but this is REALLY a stupid idea. Just something else to go wrong. GM has long forgot the phrase "keep it simple".(kept the intergral regulator design that has served well since the 70's) As far as battery life I think it will prove out to shorten it not extend it because it will be cycled more between charge and discharge while driving. Years ago GM used to make a altenator for OTR rig that had a 4 position jumper on back of it that let you tweak the voltage output if need be for max battery life in .2v volt steps to limit boil out on constant driving in warm weather if need be. This new system depends on the car deciding and experiance has shown that they are not very "smart" about a lot of things. I can see the light flickering now in brightness. You know they come have likely saved as much fuel if they had went to high power LED's for DRL's and saved 40 to 50watts of power and a fractional amount of fuel but this method looks better in a tech article at first anyway. ALso given how cars are more electrical power hungry than every conventional wisdom would say not to do this. What I am waiting for is the next car voltage standard because 12V is not going to be very viable too much longer. 24 volts could work because it has some usage now and 28 would be nice because it is a aircraft standard too but I have heard that it will likely be in the 40 to 50 volt range when it happens. I would have been more impressed if GM had taken the first step on a new standard rather than this new feature. ----------------- TheSnoMan.com
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You're ten years too late...

Because you don't understand it doesn't make it stupid.

Integral voltage regulators fall into the "just something else to go wrong" category also.

GM voltage regulators have been temperature compensating for quite a while now.

Based upon?

When the only tool you own is a hammer, every problem looks like a nail.

Which part of; 'the system is disabled when high current devices are switched on' didn't you understand?

42 volts is what has been rumored/predicted for over ten years Mr. van Winkle, but the 42 volt standard is/was aimed more at task specific goals than the storage abilities/generation capacities of the current 12 volt standard.

As usual, Chrysler will do it first.
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As far as battery life I

This interests me. Years ago when the regulator was separate, they definitely were temperature compensated. The newer cars have the regulator in the alternator. What temperature is it sensing? Can't have anything to do with the battery temperature.
Al
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wrote:

Since the compensating circuit was contained in the voltage regulator, the alternator and VR itself.
Back in the early 90s Mohammad Samii wrote an excellent article in Automotive Rebuilder on the CS series alternator, the article contained complete wiring diagrams including the voltage regulator, temperature compensation was done via a diode cascade.
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The schematic of the internal regulator is in many standard repair manuals. Again, the temperature of the alternator has nothing to do with the temperature of the battery. On my Dodge truck the voltage regulator is in the ECM, and my scanner will read the battery temperature. Beats me where it gets it. Battery voltage is directly related to temperature. So I imagine it could read the voltage before you start the engine. But the under hood temperature has to change as the engine warms up. Old GM cars had the voltage regulator mounted very near the battery, that made sense.
About GM designing a different way to control the alternator. Makes absolutely no sense to start a car and have the alternator dump 85 Amps into a slightly discharged battery. That just shortens the life of the battery.
Al
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I could check on your specific vehicle, but in general it makes perfect sense to use the IAT sensor as it is typically right near the battery, and if not then at least it's underhood.
Toyota MDT in MO
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wrote:

I see plenty of rudimentary block diagrams in the manuals but not many actual diagrams of VR circuits. Even my Mitchell on Demand doesn't show the actual internal VR circuitry.

Agreed.
Mine also.

Battery temp sensor which is surface mounted in the SBEC. (in the case of my truck)

Apparently Snojob disagrees. <shrug>
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On Tue, 06 Feb 2007 01:06:15 GMT, aarcuda69062

Oh I did not know it was 2017 gee....

You are the one that does not undewrstand it because I understand it logic (poor that it is ) far better than you ever will as I have a EE back dround not a ST (Shade Tree) like you

Not hardly, they have proven to be quite relaible and provide a stable output and have long had provision for remeote sensing to so the voltage level can be set in distribution block not at alt output.

Know kinding huh???? Like you are the only one that know that. YOur answer show that you did not even know about this commercail altenator yet you are a expert on these subject too huh. You are a Joke.

Dealer repair trips and many consumer complaint of "cannot duplicate it" so they say it is normal or nothing it wrong.

I would expect that from a ST like you, we sometimes called you guys hammer mechs too. You must feel lonely being one so you try to bring others to your level.

You are REALLY clueless arent you? This vain attempt to work within the limitation of a 12 volt system that need to be upgraded is a cluster fart. It is a very poor attempt at a bandaid fix but people such as yourself with just enough knowledge to be dangerious think it is cool and they bank on guys like you being impressed and buying into this and then telling you it is normal when thing do not go as planned.

Not true. A higher standard is coming I just do not know when. even 24 volts would cut amperage in half to deliver same wattage to load and limit wire size needs and altenator capacity because believe it or not it is easy to make say 75 amps at 24 volts than 150 amps at 12 volt with altenator and smaller wiring can be used to because again less amperage is needed.

TheSnoMan.com
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wrote:

When will you provide proof of this. You have been asked numerous time to substantiate this.
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What prove that you are clueless? (your posts do that) Or the theories and concepts involved? You could go to college and get a degree like I did and my kids are and find out first hand how and why rather then wasting my time and others with your dribble. It would be a waste of my time to explain it otherwise to someone like you so closed minded and bent on being a troll and causing problems rather than actually learning something or helping. ----------------- TheSnoMan.com
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wrote:

I think that what all this say's is "Like all my other BS answer's, my education claims are BS as well". You could have said that in one sentence. Maybe you and dave are the same person.

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It's not, but it's not my fault if you don't get it.

What -exactly- IS the definition of "A EE back dround?" For all anyone knows, it could mean that at one time, you were the night janitor at a Square D plant. Then again, it wasn't -that- long ago that you very handily demonstrated that you didn't have a clue as to how a GM electric fuel pump is powered.

Based upon your limited exposure...

GM hasn't produced a reliable charging system since the 80s, and even then, the VRs still failed.

Stable output does not equal correct voltage for the ambient temperature.

Please describe where this remote sensor is. I'm thinking that it's sitting right next to the Ram V-10 knock sensor.

What Is that gibberish?

Far be it for me to start acting like you.

You figured all that out from one minor statement, eh?
You are a Joke.
That title was long ago awarded to you.

If you are such a superior mechanic, why are you making many trips to the dealer for repairs?

Says the guy who just a few days ago described hammering together a Dana rear axle, who described how he laps down a pinion gear to install the pinion bearing, the guy who even though he is such a superior mechanic, sent his own truck to a repair shop to have the intake manifold gaskets replaced by what he calls a "shade tree" a "hammer mechanic."

Tell me, after you turn those pinion gears down on your lathe, do you cross your fingers real tight in hopes that the bearing won't spin and weld themselves to the shaft? Is having your fingers crossed the reason your typing is so horrible?

Where exactly did I say I was impressed? You really should work on your reading comprehension.

Prove it.

No shit. There's a lot you don't know.

What is an "altenator?"

And you probably think that smaller wires is a good thing...
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You missed the point. The pinion depth shim is not on the pinion shaft in a Dana. You only put the bearing on once.
Al
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wrote:

No I didn't.

Correct.
Indeed. But I don't see where I referenced his pinion lapping antics to setting up a Dana, do you?
I was merely pointing out that he doesn't discriminate when he's butchering any rear axle though... Yeah, I probably could have worded it all a little clearer.
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