Hi guys , I have been running my new to me dodge ... I have noticed a delay in the charging system ... seems like 15 to 20 seconds ... then it starts charging ..
Is this normal or is my alternator taking a crap ...
Thanks guys

Greg

 

Mine does it also.

 

Are you talking about right after start up? If so then it is your grid heaters cycling and doing thier thing. There are 2 of them and they draw 95a each,this will bury your volt meter as they cycle on.They should do this for a couple of minutes or until you reach 25mph.

 

If you have grid heaters, the drop is caused by them heating the intake air. Usually only occures below 40* F and will cycle until the intake air warms up.

 

I agree with the others... Likely just both 95amp grid heater circuits suckin' some serious amps...

Make sure it is actually the Alt not putting out anything for a period of time, and not just low voltage because the 190amps of grid heater current overwhelming your 130amp alternator which WILL pull the battery bus down. If the alt truly isn't genning, try cleaning/replacing the worn brushes.
I had that happen once where the alternator had to warm up enough to allow the greasy brushholders to let the carbon brushes touch the slip rings.

K.

 

I don't belive it is the cycling he is refering to. It just does not start charging right after start-up it will sit and drain the batts for around 30 sec, well after oil pressure comes up. I just noticed yesterday that mine does it as well(the reason I looked at this thread this morning).

Randy

 

Its the grid heaters cycling. It will do that as long as it is cold outside. Like someone else just said they will stop cycling after intake air is warm enough or until you hit around 20 mph.

 

Hi Guys ... I don't beleave its the grid heaters cycling ... my truck is in side a 80 degree shop ...Lucky truck ...LOL .. It dose it every time ... it's not charging during that time... about 15 to 20 sec's . I was wondering what would cause that .
I'm glad to see I'm not alone with the delay ... I am new to dodge , are the regulators built into the altanators and what trigers the charging cycle ... i have great oil pressure ... is there a pressure swith that controls that .

Thanks

greg

 

When You start your truck does your wait to start light come on?

 

Yes I turn the key , the wait to start light comes on and cycles , it gose of in about 5 to 10 seconds , then I start the truck and you can watch the volt meter for about 15 seconds it stays around 12 volts the it shoots up to 14 volts and its fine .
Thanks

Greg

 

Are you running a factory alternator?
My other vehicle has an aftermarket 1-wire GM alternator that does a similar dance.If you start it up and leave the engine idleing,the alt. will never charge.Only after you blip the revs above 2000RPMs, will the alt. start putting out.Then it will charge and maintain 14V at any RPM,including idle.
Im guessing its just the nature of the 1-wire setup,since the regulator and load sensing circuitry is all inside and running through 1 wire to the battery...

 

It's normal.

 

The wiring looks pretty stock to me ...the truck is new to me , so I can't really tell about the history.

Thanks

Greg

 

Greg, I really don't think you have a problem.. My truck appears to do the same thing until I get above 20mph when those heaters are disabled.
BUT.... For peace of mind without turning any bolts or screws, try this...

A quick way to conclusively find out if the alt is really not putting out -vs- those hefty air intake heaters pulling the volts down, is to actually place a clamp-on ammeter around the alternator output lead to measure its output...
There are some simple, round, hand-held ammeter looking devices with a crude amp scale that will indicate output, all the way up to expensive digital AC&DC clamp-on ammeters that will display current to several decimal places...
Borrow (or buy) one of those cheap, round handheld ammeters from an auto parts house, and just see if it is putting out ~100+amps on a cold start... If no movement, THEN start digging into the charging circuit...

FYI:
-The voltage regulator circuit is built into the TCM.
-The crankshaft sensor mounted above the harmonic balancer tells the TCM the engine is running and it's OK to energize the alternator field.
-The TCM also senses battery temp via a temp sender under the left-hand battery box and tailors the charging voltage -vs- battery temperature.

K.