Flickering Battery light

[Bird-o-Prey]

I have been driving the car for a couple of months now with the new battery (brand new Gel Exide battery with 750 cold cranking amps) and all seemed well.  I filled up the tank on the car on Thursday afternoon and parked it.  I went to the grocery store today and when I started it up, I noticed the battery light was flickering.  The alt. gauge is sitting steady right where is should be, the oil pressure guage is running steady between 38 & 43 lbs (it started working again after I switched to 10W40 from 20W50) and the vac gauge is working too.  When I went out, the car started right away with out any trouble and it drives with no problem.

I haven't been under the hood in weeks!  Any idea what might be going on here??? 

Cheers

[DaemonForce]

Sounds like a loose connection somewhere or your alternator is about to fail.

[Bird-o-Prey]

The altenator is less than 4 months old.  It is a brand new Bosch.  I don't see how something could suddenly come loose after 4 days of not being used   I was hoping that the battery was just low and needed recharging.  When I accelerate the light almost goes out.  I will put it on the charger and see if that helps.  When I replaced the altenator, I used di-electric grease to prevent corrosion on all my connections, including the battery posts.

I am at a bit of a loss.

Thanks

[IowaEagle]

Is the alternator belt slipping or loose?  What is you idle set at?

[carnuck]

It could be a weak regulator in the alt or it's sensor wire may be frayed. I see that a lot on GM style alts.

[Bird-o-Prey]

Hi Doug.  The idle is at +/- 750 rpm with the MC2150 on it.  The belts are tight.  The Alt is new.  It was running tickety-boo for the last 3 months or so.  I parked it for 4 days and now I have a flickering Batt light.  The volt meter in the instrument package is holding steady right where it should and doesn't twitch (except when a switch is flipped or the intermittant wipers go off, which is to be expected, then it just moves a titch indicating a power draw for a device).  The battery has lots of juice.

I am not sure it is the Alt.  The lights don't dim when the idle speed drops from accelerating to idle speed.  Even if I have the blower on high and the wipers on! 

I am pulling whats left of my hair out trying to sort this one out. 

Thanks

[jim]

Could it have to do with a faulty ground somewhere?

[Bird-o-Prey]

That is probably true, however, I am vexed by how the ground can suddenly become faulty when the car has just sat for 4 days and no one has been under the hood in weeks.  I checked all my connections a little while ago and all seems well.  The battery light is usually indicative of a problem in the charging system, though, isn't it?

Thanks again!

[83Eagle!]

These old birds are odd when it comes to electrical stuff. Does sound sound like the alternator is on the way out.
That's what the issue was with my battery light anyway.

[Bird-o-Prey]

Now for something completely different.  I had a chance to drive the car today for about an hour or so.  By the time I got home, the battery light has stopped flickering, EXCEPT, when I drive over a really bumpy section of snow and ice.  Then it flickers just a little (barely visible), otherwise, the battery light only comes on when I lay into the pedal from a dead stop.  Could it just be a low battery??  Is it possible there was just some moisture in the alternator??  I am totally confused here.  The alt meter in the car is steady on 14 amps with no accessories running and about 12 1/2 with the lights and wipers and blower running.

I will take it for a long drive tomorrow when I go to work and see where we sit then.

Thanks for the input.

Cheers

[craigp29690]

I've got one of my toys that the battery light stays on all the time.  When I first got it I figured bad alternator and changed it out, no difference.  Bought one of those plug in the cigarette lighter volt meters to see what was going on with the charging circuit and no issues.  Voltage at battery with all the electrical accessories runnig is right where it should be.   Short story, there is an Exciter Circuit that lights the Battery Light and somewhere in that circuit there is a break, short or bad connection. 

[carguy87]

14 amps or 14 volts?  It sounds like your alternator belt is loose. These old birds have constantly on alternators and run between 13.5v and 16v if your going down the expressway.  If it dies when you step on it, your belt is probably slipping under the load.

[Jurjen]

Here is a nice link to understand our alternators:
http://www.alternatorparts.com/understanding_alternators.htm

[Bird-o-Prey]

Thanks Jurjen!  I have been running the car since then and the light has all but gone out.  In fact, the only tine I se it now is if I go over a bumpy road.  Then, it flickers just a bit.  With that being said, though, I have tested all the wired connections with the motor running and wiggling wires does not make the battery light come on.  So, there must be something loose inside the altenator??

Still working on it.

[Jurjen]

Is your Bosch alternator really a new one or just a reman?
It looks like the diode trio is making bad contact or on its way out.
Those can be bad from new too.