Possible voltage regulation issue?

[HEXEM]

Hi all,

After getting my car back from the Holden dealer (3 weeks and 2 new motors!!) All seems to be running nicely.

One thing I have noticed is the voltage meter on the dash (the 3 window red LED type) seems to be a bit erratic. By erratic, I mean the voltage will climb to 15.3volts after starting the car then climb down contantly to about 13.2volts and level off somewhere around 13.9, this will occur any time of the day and after any lenght of driving (5 to 30min trips). This has only be noticable since they installed the new motor.

The other thing I've noticed is when its sitting around 13 volts and I then drive off the voltage will increase to back up to 15 (based on engine revs etc) and eventually settle back. Thinking that I had a possible loose connection on the battery I reseated them and made sure they were tight. I also ckecked the connections on the alternator. While this was occuring when parked in the basement at work and the engine idling my headlight would periodically flicker (bright then dim etc).

I went out to see my dealer and spoke with the tech and he said that its normal for the voltage to change. I understand this as the BCM controls the voltage charge rate etc, however I have never had issue with flickering headlights or such erratic voltage variances.

I had them SPS the BCM to change the charge rate from standard to Police mode. This had no immediate effect. Last night I was making sure earth connections for the engine harness were tight and also the large black plastic junctions for the main wiring harness (one at the firewall and the other near the engine bay fuse box).

This morning things seemed a little more settled. No headlight flickering or erratic voltage readings. When I took the car out tonight and the headlight were on the voltage crept up to 15.4 volts and after a few minutes of driving it dropped back to 14.2.

I am hoping that the BCM or alternator is not on its way out. There are no other electrical issues I can tell (such as dash light dimming, indicators not turning off etc).

Other that have a MY9.5 or MY10 with the same display could you tell me if your voltage readings are up and down like a yo-yo in quick succession? Or others that might be able to give me some options to look further into?

Cheers
Phil

P.S. First up I had thought it might have been a low voltage on the battery after sitting for some time. So I gave it 48hours charge on the C-TEK 7000 calcium charger.

[RiCeY]

Changing to police mode was pointless as police cars have two batteries.

[HEXEM]

Changing to police mode was pointless as police cars have two batteries.

Probably, I will have it changed back to normal. What do you propose could be the issue or something to look at in more detail.

Cheers
Phil

[RiCeY]

I wouldnt worry about voltage fluctuations too much, it will let you know if theres too much or too little voltage.

As for headlights flickering this is normal if it happens when the thermo fans kick in and out.