Charging Problem?

[GTOWag]

I recently noticed that my volt meter takes a few minutes after starting the engine to move from battery voltage of 12 volts to a charging voltage of approximately 15 volts. I have a friend that claims he has the same thing happen to his Cummins. It doesn’t matter if the engine is a cold start or after it is warmed up. It happens on every start. Is this normal or is it a sign of something going wrong?

 

[bmoeller]

Might want to move this to the 3rd Gen forum for more visability.

 

[Steve St.Laurent]

It's the heater grids cycling which may happen in the cold regardless of a hot or cold start - it all depends on intake temperatures. Also, I'm moving this to the 3rd gen forum where it will get more exposure.

 

[GTOWag]

Thanks for your help in moving my post. Also, the heater grid cycling does not affect the movement of the volt meter as I am describing it. The volt meter continues to stay at battery voltage constantly until it decides to finnaly come up to charging voltage whether it is a cold start or a hot start (makes no difference). Thanks again.

 

[rbattelle]

By "hot start" do you mean "hot outside temperature" or "hot engine temperature"?



-Ryan

 

[ENordstrom]

I have noticed this on my new truck also. I am actually going to time it to see if it stays low longer at lower temps, ie; the truck is cold vs warm. Since I am currently living in Mass. it will be June before it starts warming up here... .

 

[GTOWag]

By "hot start" I mean that the engine is up to normal operating temperature with an ambient air temperature around 55 to 60 deg. The engine can be at normal temperature, shut down and restarted and the volt meter still has the delay in coming up to charging voltage. Delay varies from one to three minutes. If the engine were to remain at idle, I don't know how long it might remain at battery voltage. It only comes up to charge voltage after the truck is driven a short distance. Increasing engine speed while not moving has no effect.

 

[Buzzer]

To me it sounds as if the heater grids are cycling. When you move to approx. 15 mph they cut out. I know its already been mentioned but just a thought.

 

[rbattelle]

To me it sounds as if the heater grids are cycling. When you move to approx. 15 mph they cut out. I know its already been mentioned but just a thought.

The grid heaters cycle independent of the engine temperature. They are only a function of ambient temperature. They are supposed to come on below 66*F. That's all it is. Run a quick search on "grid heaters" and you'll find thousands (okay, I'm exagerating) of threads about the same thing.



If people keep complaining about it DC will change the voltmeter to one that "conforms to customer expectations" just like they did with the oil pressure gauge.



-Ryan

[I'm not being mean or condescending in this thread. I mean no ill will toward anyone. If I've said anything even remotely wrong please someone correct me. ]

 

[mikepvg]

Mine does the same thing. The interior lights dim & then go bright. Kinda ridiculous really. But, Did this since I drove it off the lot. I chaulked it up to Dodge design incompetence (normal).

 

[joeyou]

I recently noticed that my volt meter takes a few minutes after starting the engine to move from battery voltage of 12 volts to a charging voltage of approximately 15 volts. I have a friend that claims he has the same thing happen to his Cummins. It doesn’t matter if the engine is a cold start or after it is warmed up. It happens on every start. Is this normal or is it a sign of something going wrong?

It is because the grid heater is on.

 

[tractorseller]

You guys saved me a trip to the dealer . I noticed my interior lights going dim and then brightening the other night when I started the truck to show my son how quiet the engine was. I also heard a clicking noise that appeared to accompany the dimming and brightening. I figured I had a problem . If it's normal I'm blowing it off. I don't know if Dodge service departments are half as bad as GM service departments, but if they are I'd prefer they didn't touch my truck :-{} .

 

[EEdmondson]

This has been discussed many times and it is N-O-R-M-A-L!!! The voltmeter does not read your voltage directly... it is fed by the computer just as the oil pressure is. The lights dimming is a result of the grid heaters cycling... they draw more current than the alternator puts out but for short durations. Completely OK. Correct me if I'm wrong.

 

[jelag]

I have both an 04 and 05, and I can be almost 1. 5 miles from the house on a cold start before the guage goes up... . I assume it's controled by the computer... and that the engine has to be stable. . after all... . a 135 amp or what ever it is... . is going to bog the engine down at idle after a real cold engine start... could be something to do with emissions... or engine stability... but can only assume its a function of the engine control system... .

 

[Jgoldsberry]

YAY - I noticed this this morning - glad its normal - I am waiting to make sure no bugs are apparent before the new bombing run

 

[JHardwick]

I was under the impression that the charging system was disabled during the grid heater cycle to eliminate taxing the charging system.



If this is true, which I believe it is based on the voltmeter reading, the grids are operating on the batteries only. When the grids cycle on/off for the 2 minute period or whatever it is, the lights dim and motors such as wipers and blower slow down because the grids are pulling a lot of voltage from the system.



Once the cycle is over or a certain speed obtained, the charging system kicks back in.



Am I missing something?

 

[Steve St.Laurent]

I don't believe the charging system is disabled it's just that the grid heaters are pulling in a LOT of juice and drawing more than the charging system can put out. The heater grids pull 95 amps EACH (x2) - 190 amps total. The stock alternator is a 136 amp unit. That's why you see a load put on the system and the draw down on your gauge and dimming lights.

 

[JHardwick]

I don't believe the charging system is disabled it's just that the grid heaters are pulling in a LOT of juice and drawing more than the charging system can put out. The heater grids pull 95 amps EACH (x2) - 190 amps total. The stock alternator is a 136 amp unit. That's why you see a load put on the system and the draw down on your gauge and dimming lights.

This could be true. But, when the lights are cycling dim/bright with every heat cycle, the voltmeter stays pretty constant down around 12 volts. As soon as the entire timed event is over, the guage instantly "pops" up to 14 volts.



I dunno

 

[rbattelle]

This could be true. But, when the lights are cycling dim/bright with every heat cycle, the voltmeter stays pretty constant down around 12 volts. As soon as the entire timed event is over, the guage instantly "pops" up to 14 volts.



I dunno

You can thank DC for THAT fine piece of programming. Remember, although the volt meter reading is "real" the needle placement is controlled by the computer. So all they do is force the computer to stick the needle low during heating cycles because people would complain that something's faulty if they actually saw it bouncing around with the heaters. As it is, people still complain which is why I fear the voltmeter will be the next gauge re-qorked to "conform to customer expectations".



-Ryan

 

[EEdmondson]

I have one of these to read true voltage. It is a little slow but seems accurate.

http://www.cetsolar.com/voltmeter.htm