Electrical problem?

[Cat Fuzz]

I've noticed lately that when I'm sitting at a stop light, engine idling and in drive, my lights flicker. When I rev the engine it goes away. I'm using the stock, externally regulated charging system on my truck. Has something gone bad or do I have a bad connection somewhere or is this just normal (not likely)?

[BIG ORANGE]

Could be regulator or maybe alternator!

[Cat Fuzz]

Well, I just replaced the alternator. Was under warrenty. The voltage regulator is just a switch. It either allows the battery to be charged or it doesn't.

[Chevy67Tk]

Voltage regulators are more than just a switch, yes they apply power to the field coil in an on and off fashion but they do it very fast to limit the output of the alternator. At higher Rpm’s it will be doing it at hundreds of times a second, at lower Rpm’s the alternator is producing less voltage so the relay is cycling slower and the flickering you are seeing is this cycling. Alternators will produce much more than 12 volts if left unchecked by a regulator. So do you have a problem with the regulator, maybe, they are mechanical and mechanical things tend to wear. I had the same problem your describing with my truck and it ran and charged the battery just fine for 20 years that way, but mines not a daily driver. I have since changed to a single wire alternator because I wanted more amps available for things like electric fans.