Voltmeter with high reading?

[DGamelin]

I have aways believed batteries were go for up to 8 years after that they should be changed. The ones in my 04. 5 are at that age but they still test good. My voltmeter is reading a little higher in the last 3 mounts it got me concerned. It is running 15. 5 to 16 volts the batteries are not over charing, has any body seen this?



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93 250 2wd xcab 354 auto 305455k

04. 5 3500 4wd cc dully 6speed 373 164220k

 

[Prairie Dog]

You mean the VM in the truck or a hand-held? If you mean the meter in the truck then I would check it against a "real" meter.

 

[DGamelin]

The one in the truck recently. I checked it with a hand held meter a month or so ago. I don't remember what it read but I think it was a little high. I keep forgetting to look into this. Seems I only remember when I'm on a run and see the gauge climbing. The longer the run the higher the gauge climbs. When it first starts up the gauge reads the way it's suppose to. Tomorrow I've got to send someone on a part run. As soon as it pulls in I'll check it with a meter. Most of the trucks that come into our shop, it's pretty obvious that the alternators are shot or the voltage regulator. I just haven't seen something that climbs over a couple of hours. I was curious if someone had seen this before? Could this be a sign of old batteries? I guess you're figuring the gauge in the truck could be bad.

 

[jclark5810]

At 8 years old, and with a U. P. winter on the way, I'd just replace them. It's far better to change the batteries out on your terms, rather than when they decide to quit. Might be fine now, but why risk it. I swapped mine out on the 04. 5 at the seven year mark, spendy but never had to worry about it. My $0. 02.

 

[jelag]

I've watched my trucks a lot and have never seen a digital voltmeter reading over 14. 5 V, but I know that when a battery is sulfated up, it requires a higher charging voltage to charge ... I can also assume that at some time during the time the engine is off the ECM might look at the static voltage level and decide to move the charging voltage up... As this requirement for a higher charging voltage occurs and the current flow and temperature at the battery doesn't rise to an excessive level it won't boil out the water...



I can absolutly tell you that if you have 16V or higher as a real charging voltage, lamps, and other electronices can and will be damaged... and this can be costly...

 

[Prairie Dog]

I checked my truck out and this is what it's doing. My V meter has always sat in about the same spot and I consider the system healthy - batts are 2 yo.
The eng was still fairly cold after driving only 4 miles but the reading was very stable.

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I'm thinking that 16V would be the next big line.

 

[AH64ID]

It is probably due to the colder weather. My voltage will go as high as 14. 94 (at the OBDII port) when the batteries are cold soaked below ~35° (give or take). Once they warm up they are 14. 6V-14. 75V. As rpms fluctuate rapidly the voltage will spike up 15. 00V-15. 06V and set off the high voltage alarm on my Ultra Gauge. Once the thermostat opens and additional warm air hits the engine bay the alarm wont go off anymore. I will be raising the alarm to 15. 1V for winter ops, and don't expect to get any dings.

There is a battery temp sensor under the drivers side battery that is part of the charge voltage logic.

I've watched my trucks a lot and have never seen a digital voltmeter reading over 14. 5 V, but I know that when a battery is sulfated up, it requires a higher charging voltage to charge ... I can also assume that at some time during the time the engine is off the ECM might look at the static voltage level and decide to move the charging voltage up... As this requirement for a higher charging voltage occurs and the current flow and temperature at the battery doesn't rise to an excessive level it won't boil out the water...

I can absolutly tell you that if you have 16V or higher as a real charging voltage, lamps, and other electronices can and will be damaged... and this can be costly...

As I have stated in a few threads I am pretty sure your charge/volt logic is old and needs to be updated. You would get higher voltage if you updated your software.

 

[DGamelin]

Thanks Guys, I checked mine with a hand held and got 14. 8, the truck has never had an update. The picture you've got Prairie Dog Is right where mine is running. I could have sworn that mine use to run straight up on 14. It is probably just my bad memory. We have a couple of forklifts here that need batterys I can put these in them and get new ones for my truck.

 

[rscurtis]

Next time you have what you call summer in the UP, you'll see the batteries drop down to around 14 volts.

 

[Prairie Dog]

Thanks Guys, I checked mine with a hand held and got 14. 8, the truck has never had an update. The picture you've got Prairie Dog Is right where mine is running. I could have sworn that mine use to run straight up on 14. It is probably just my bad memory. We have a couple of forklifts here that need batterys I can put these in them and get new ones for my truck.

You know what? Me too. . I could have sworn it used to just point up at about 14 but kept thinking I was imagining things (again?).
I installed a Smarty Jr. a while back and wonder if I got a more recent SW update that changed where the meter sits.

 

[cerberusiam]

Yeah, that gauge is about as trustworthy as the guy selling bridges. Mine has sat in the exact same spot thru a bad cable end and 1 dying battery when I know it was charging more than that. That was with multiple Dodge updates and Smarty versions. The only differnece it has ever had was sitting under 14 when the system quit charging completely from a bad cable. I don't thin it eve rshows high charge and only drops when the charge system shuts down completely.