Hoopty appears to manage battery voltage....

[mwilson]

Noticed this last year and 40,000 miles ago. Went right in to a panic, OMG how much is an alternator going to cost, new or reman, how to change it, etc...

I have decided it must be normal. Probably why I changed out the OEM battery last summer at 8 years old.

It seems quite happy at 12.8 volts. When you add a load such as the rear window defroster it slowly ramps the voltage up. Remove the load and it slowly ramps back down. I really think that this is by design.

 

[GCroyle]

Cut some black tape, looks like 1/2" X 2 1/4" apply over the offending display. Done.

 

[mwilson]

Oh, I can switch it to other stuff. Just fixated on that one...

Gotta shut phone off before they throw me off of the plane.

 

[chipster]

Noticed this last year and 40,000 miles ago. Went right in to a panic, OMG how much is an alternator going to cost, new or reman, how to change it, etc...

I have decided it must be normal. Probably why I changed out the OEM battery last summer at 8 years old.

It seems quite happy at 12.8 volts. When you add a load such as the rear window defroster it slowly ramps the voltage up. Remove the load and it slowly ramps back down. I really think that this is by design.

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Mikey, Mikey, Mikey, you must have brass balls, covered in leather double stitched!! Taking pictures at 75 M.P.H.!!!!!!! what do we do to top that????? :-laf :-laf

 

[MichaelOverfield]

Interesting.. if you had a battery last 8 years, that is well over typical, so it may well be regulated to switch to a trickle charge, that said it seems unusual for GM.. normally these are internally regulated alternators. It is possible that it lowers output with lower current load, then ramps up for higher current load.. this would also permit rapid charge (higher current demand), then taper off when a battery was fully charged . A good way to look for this.. see what it reads shortly after start up (been sitting for awhile).. the demand to starting cycle and idle time (normal internal and car trickle battery load) should want the higher voltage and thus current to charge that energy back into the battery.. if you still have 12.8 V following sitting time and a start.. I'd say you are having an alternator issue. You'll want to get that energy/charge back, but following that a taper when fully charged will extend battery life if that is what you are seeing - it would be good. Come to think of it.. I do see a similar pattern on my GM car (96 Saturn).. though not as wide a range from 14+ to 12.8V, mine goes lower to about 13.5V after it's been running for some time. That said, I'm on the 3rd alternator, and 3 battery with 190K miles on that car.. If you are on original alternator at 133K you are doing very well!

Oh, if you go with replacing the alternator, as a former parts store employee.. I HIGHLY recommend only NEW units, or get the parts and rebuild your own (Bearings, brushes, Diode, Regulator). I'd estimate that about 1/3 of the reman units we sold came back soon after as defective.. it is not worth the small savings in cost to do the work of the replacement twice, time is worth something!

 

[TFucili]

Lazy regulator-rap on it with a screwdriver handle...

 

[AH64ID]

I had a GM rental car a couple months ago and on a long drive I noticed the same thing. I was in the middle of Yosemite when going up a hill and the voltage went from 14.x to 12.x and thought I was in for some roadside assistance but 40 miles later when I rolled the window down the voltage came back up momentarily.

My 2007 Toyota Tacoma would go into a float after an hour or two but the Dodge never does.

 

[GCroyle]

I really think you need to flash the generator field windings. A clear case of Digital TMI.

 

[TFucili]

I really think you need to flash the generator field windings. A clear case of Digital TMI.

I think I have a growler around here somewhere.

 

[mwilson]

Alright, just put my Marriott rewards into play for free wi-fi, It's all good now...

It will ramp up the voltage to 14.5 when first started, in the summer it takes about 10 miles before it settles down under 13. In the winter with lights, heater, heated seats and other electrical thingies it takes longer but will still drop down to low - mid 13's. But even in the winter once the seats turn down and the blower fan slows it will drop to 12.9 on a long drive.

I think that it is a fairly intelligent voltage management system. Figure that the lighting is all LED inside, tail and brakes lights are LED as well. Headlights are true HID which I suspect draw less power after they initially start. That only leaves two incandescent 4157 turn signal / drl bulbs and a pair of 194A parking lights. It makes sense to me to cut the rate of charge back to the float point. The 8 year old battery would still start the car every day but could not be trusted to set a week.

 

[mwilson]

Lazy regulator-rap on it with a screwdriver handle...

I'd have to pull the radiator to tap it......

 

[mwilson]

I think I have a growler around here somewhere.

OMG, haven't heard that word since I attended technician school back in the 70's....right up there with dwell meter......

 

[mwilson]

I'll put a generator on it and use it for a starter as well like a Cub Cadet. Then if the starter goes south I won't have to pull the intake manifold off....

 

[mwilson]

Mikey, Mikey, Mikey, you must have brass balls, covered in leather double stitched!! Taking pictures at 75 M.P.H.!!!!!!! what do we do to top that????? :-laf :-laf

I know, but it's such a smooth machine you just lay the phone sideways on that leather encased steering wheel made from some old cow and tap the face of the phone.

Now doing it in a '97 Ram is a whole other story......

 

[mwilson]

Mikey, Mikey, Mikey, you must have brass balls, covered in leather double stitched!! Taking pictures at 75 M.P.H.!!!!!!! what do we do to top that????? :-laf :-laf

And also, I am not in a heck of a lot of traffic. There might be two cars and a log truck in the distance to the front and a couple of more cars to the rear. Pretty solitary compared to what most of you guys go through every day.

Moose and deer are my commuting worries.....

 

[chipster]

And also, I am not in a heck of a lot of traffic. There might be two cars and a log truck in the distance to the front and a couple of more cars to the rear. Pretty solitary compared to what most of you guys go through every day.

Moose and deer are my commuting worries.....

yeah, those critters will total your vehicle sooo QUICK !!! you should be 8 feet tall now. that`s how hard I was pulling your leg!! I never thought you`d do ANYTHING to endanger your self or others. keep up the good posts, Mike. your buddy, Chipster

 

[mwilson]

In the spirit of Moose this happened on June 29th....in Maine of course!!! The danger is the flailing hooves if it doesn't die quickly.......

"Moose vs Car....moose won. Luckily the individual driving will walk away with only minor injuries. Happened in Shirley/Monson on Thursday night. The car was brought to Greenville where it was quite the tourist attraction!"

Lucky, Lucky Lucky........

 

[TFucili]

OMG, haven't heard that word since I attended technician school back in the 70's....right up there with dwell meter......

I actually did have one, but left it behind when I moved. My uncle ran a service station for 40+ years, and was as old-school as they came. You R-E-P-A-I-R stuff, not buy some parts house junk. Different world today. I'm so glad I learned the old ways. It has bailed me out innumerable times.