What is the normal ammeter voltage for my 07 Denali? For the past three years my ammeter has read 14 volts or slightly higher at all times. Last week my vehicle was dead in the driveway. I charged the battery overnight, took it to the dealer and noticed the ammeter was reading about 12 volts on the ride over. They said the battery failed the load test and replaced it. Since then I've been watching the ammeter and it reads just over 14 volts after start-up and in a few minutes drops down to 12-12.5 volts. This morning it stayed at 14 volts for over 30 minutes of driving. My C6 Never drops below 14volts on the ammeter. The dealer says 12 to 12.5 is normal. If that's the case, then the Vette and my Denali have been abnormal since new. What gives?
Normal Ammeter Reading?
- Thread starter GMCSUV
- Start date
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Mine fluctuates between12 and 14 plus. I hear the computer controls the charge rate to save fuel and preserve the battery.
Thanks for the response. I'm thinking the old battery, which died early, never was able to build a full charge and that's why the voltage regulator allowed a 14 volt constant charge trying to do so. Now that I have a new battery, the charge starts at over 14 volts and scales back to about 12.5 which seems normal to me. I suppose if your ammeter reads 14+ volts at all times, it's time to look for a new battery! Comments welcome.
Okla-by God-homa
New Member
BULLS*** since the day I got my Yukon the meter has been all over the place. Battery has been dead 7 times since new. Dealership one time told me they tightened a loose bussbar and that should fix the problem....that was 3 dead times ago. Does ANYONE truly have an answer to this vexing problem?????
I am sorry for where you live and I won't hold that against you! The ECM does control charging during operation. That said, something is wrong. You know that. What you need to do is to check the charge rate. See if indeed it is charging. I suspect it is. After that check any mods done to it for open circuits. If you've owned it since new then you know what you've done. if not, check everything. Lights, radio and amps. Put a meter on in while it is off. The current is going somewhere!
Also,jk about where you live. I have visited there once.
Our 08 does the same thing, 12v to around 14 v. I noticed it fluctuates more when the AC is on and the Monitor with video is running. I noticed that the positive side of the battery post had a lot of corrosion, so I cleaned everything up real good, reassembled and coated everything with vaseline. That was over a month ago and it seems to be holding up fine. Good luck with yours.
Okla-by God-homa
New Member
Finally Fixed ?????
Got it to the dealership.....again. This time when they ran a test of the battery it tested fine.....but, the mechanic decided to run another test later and that time it showed bad. They replaced the battery (under warranty) and thus far the ammeter has stayed above 12 volts; actually closer to 13 since. For the first 3 days after replacement it stayed above 14 but finally settled down. So far, so good, I'm hoping it's.....Finally Fixed.
My advise is to have the battery load tested at least twice by a dealer who knows what they are doing and if possible put yourself in a place where you can actually watch the process and always.....Question, Question, Question.
BOOMER SOONER
Got it to the dealership.....again. This time when they ran a test of the battery it tested fine.....but, the mechanic decided to run another test later and that time it showed bad. They replaced the battery (under warranty) and thus far the ammeter has stayed above 12 volts; actually closer to 13 since. For the first 3 days after replacement it stayed above 14 but finally settled down. So far, so good, I'm hoping it's.....Finally Fixed.
My advise is to have the battery load tested at least twice by a dealer who knows what they are doing and if possible put yourself in a place where you can actually watch the process and always.....Question, Question, Question.
BOOMER SOONER
73shark
Full Access Member
The ECM controls the charge rate. When no charge is req'd, the voltmeter, not ammeter, will read battery voltage of about 13 V. When it's charging, it'll read about 14+ V. There was a software upgrade for some of the '07s that were having run-down issues.
When we bought our 07 used in late 08 it was having run down issues and the dealer had to do the software upgrade. That being said our meter fluctuates all the over the place as well sometimes 14 sometimes 12.
tghires
New Member
Hello, I see this thread has been dead for a while, but I have a question/concern about my recently purchased 08 LTZ. My volt meter fluctuates as stated by others in this thread, I had my battery and alternator checked at a local chain parts store, and both tested to be ok, but was only showing 50% charge on battery, the guy asked if the vehicle had been sitting for a while, and because I only owned it over a month didn't know for sure prior to me buying it, he stated that due to the amount of electronics in the vehicle, the battery could have been drained, and the alternator basically just maintains the battery and probably hasn't charged it all the way up. OK, I am not a mechanic by any means, but I drive this vehicle approximately 50 miles one way to work, the vehicle sits for roughly a day and a half to two days then the same 50 mile drive back home, not to mention day to day driving in and around town. wouldn't this be enough for the battery to be charged so that it would show more than a 50% charge doing so for over a month now? If anyone has any info or advice I would appreciate it. Thanks I advance.
bladenbullet
Full Access Member
for the record it is a voltmeter and not an ammeter...normal charging voltage as a rule of thumb is in the 13.2-14.8 volt range give or take as required....there is no styandard charging voltage....the alternator has to produce more voltage than the battery has in it in order for charging to take place (difference in potential) so the battery voltage and current vehicle loads will dictate the charging voltage as required...a bad battery and constant heavy loads will require more than the alternator is designed to deliver long term and can shorten its lifespan considerably...so a weak battery gone undetected is detrimental to alternator health....this is one of the reasons many companies have gone to muti-point checks with conductance battery testers for battery and charging system quick tests...
in a nutshell....your charging system voltage will vary and there is no standard....
contrary to popular belief the alternator is a crummy way to charge a battery that is dead or failing...a slow charge with a good charger is much more effective...the old "after a jump start just run her for 20 minutes and she'll be fine" was always an old wives tale and probably bought more parts store alternators down the road than anything else...
a dead battery can take hours to even begin to accept a charge so counting on the alternator on the way to work is a shortcut to wearing it out...if the battery is not accepting or maintaining a full charge it is going to overwork the alternator...the battery is an integral part of the charging system and vehicle electrical supply....it balances out periodic heavy draws like a capacitor and helps take the load off the alternator in those instances....
the gentleman with multiple battery failures has a concern that needs attention and may require a multiple day stay at a competent repair facility to figure out whats going on with the charging and electrical system....I can think of one vehicle we had that required 3 nights with tech ii monitoring modules overnight to find an instrument cluster that was waking up in the middle of the night and partially crushing a battery multiple times a week until it eventually would kill it...same problem....three battery replacements over a year and a half span until we finally took action realizing there was a problem with the vehicle and not the batteries we were installing....
sometimes these things hide themselves well....general tests wont reveal them and parts that fail are replaced only to fail again before we realize they weren't the cause...only a result...
if it were easy everyone would be doing it....
in a nutshell....your charging system voltage will vary and there is no standard....
contrary to popular belief the alternator is a crummy way to charge a battery that is dead or failing...a slow charge with a good charger is much more effective...the old "after a jump start just run her for 20 minutes and she'll be fine" was always an old wives tale and probably bought more parts store alternators down the road than anything else...
a dead battery can take hours to even begin to accept a charge so counting on the alternator on the way to work is a shortcut to wearing it out...if the battery is not accepting or maintaining a full charge it is going to overwork the alternator...the battery is an integral part of the charging system and vehicle electrical supply....it balances out periodic heavy draws like a capacitor and helps take the load off the alternator in those instances....
the gentleman with multiple battery failures has a concern that needs attention and may require a multiple day stay at a competent repair facility to figure out whats going on with the charging and electrical system....I can think of one vehicle we had that required 3 nights with tech ii monitoring modules overnight to find an instrument cluster that was waking up in the middle of the night and partially crushing a battery multiple times a week until it eventually would kill it...same problem....three battery replacements over a year and a half span until we finally took action realizing there was a problem with the vehicle and not the batteries we were installing....
sometimes these things hide themselves well....general tests wont reveal them and parts that fail are replaced only to fail again before we realize they weren't the cause...only a result...
if it were easy everyone would be doing it....
tghires
New Member
when I posted earlier I forgot to state that my Tahoe was in my shop with a battery charger hooked up, and was there almost all day. I took it off the charger a few hours after the post when the charger indicated that the battery was charged, and I drove it to town. the voltmeter went just above 14 just after I started the vehicle, then soon came to rest at 14 and didn't fluctuate the rest of the time I drove it tonight. So hopefully it was just a weak battery and needed a good charge, we shall see. Thanks for the reply
bladenbullet
Full Access Member
if it saves one child...:happy160:
