Originally Posted by rip-tide
That is exactly what the problem is with the one wire set up. I say it a thousand times. One wire is for lawn mowers, tractors and gas powered welder type of operational conditions.
It is easily seen when a car is using the one wire deal. When looking at a line of cars stopped, the car with the dim & yellow head lights is the 1 wire set up. Three wire has the same intensity no matter what the RPM.
I not going to bother explaining the why, cause it has been over and over and over.
You will never have the problem with the 3 wire set up....... you're certainly free to ignore the advise.
I probably didn't state this right. The problem is temperature related, getting into city traffic is a coincidence. With cold startup even at idle the output has a line voltage of 14.5. Then traveling on the interstate the voltage tapers as you'd expect but falls to 12 all the while the engine compartment is heating up as the engine reaches its 195 operating temp. Since it's summer there is nothing the electrical system has to feed on the highway other than the ignition, no AC, no stereo, no lights. This condition never relates to RPM and for now is survivable. Winter with dark when I leave and dark when I return and dim all day long requires running with lights and defroster so the battery alone will not keep up with this constant load of this condition with the alternator persists.
Currently, this being summer, when I get off the super slab to go into the big city I have to turn the cooling fans on. When that happens the voltage just slips away with no regard for engine RPM. But they only need to run for 15 to 20 minutes not all the time like the winter electrical loads.
Once the engine cools with a gauge reading of less than 195 the alternator is putting out 14.5 following start up. That lasts till the temp gauge hits 195 then back to no output regardless of RPM. This cycle just repeats through the day. The battery is obviously in good shape as for the few minutes it gets a full charge rate it keeps up with the demand of cranking the engine as needed without having to connect it to a charger. But that won't last forever.
This is the second or third GM one wire that has died in this exact same way in about as many years. So I expect that there is some generic fault in these things, perhaps given the mileage I put on in a year they just wear out in this time frame. I'm not researching this any deeper than an afternoon R&R job; but I am going back to the older three wire configuration simply because my history with those is they lasted longer. But as time and the industry mantra of "faster, better, cheaper" (with emphasis on faster and cheaper so 2 outta 3 ain't bad) continues it just might be that anything today just doesn't hold up to my expectations.