On the older GM'* do they not have ways of "Load Shedding"? (i.e. when all accessories are on it minimizes use of each accessory one by one to not discharge the battery, usually at an idle situation)

I am just curious if you have the lights on, radio, rear defroster, heater, and wipers going at idle (not moving) does it run the accessories fully and run the battery down or not?

Thanks for the insight!!

No, I think it just puts more load on the alternator, which puts more load on the crank, which then opens the idle air control valve slightly to compensate.

Yeah what he said haha

I am guessing not. On mine, with lights on, heater cranking, rear defrost running, I am pretty sure that I am discharging the battery at idle. I can tell because the blinker blinks really slow under these conditions, and then picks back up as the rpm'* come back up.

That'* not good.

It is what it is. It even does it with the replacement alternator. I do know I have a good battery in the car however, and would take steps to prevent a dead battery if the voltage drops off too much. It is not that big of a deal, you just can't be stupid with it, otherwise you will be roadside with a dead battery.

it sounds like your alternator isn't charging (atleast not at idle).....it seems to be discharging the battery

The alt will fuel the electrial needs and if it cant it gets it from the battery until its death ! The alt will curve the charge rate I belive ! Good grounds and connections are very important on a maxed out acc load.

My Park Aves bith did it as well. Normal. We have to remember that a rated alternator only gives out it rated power at higher RPM'*. At an idle with all the Buick or even Bonneville'* (will the smaller alternator) you are likely exceeding the altenators amperage (which isn't much at an ildle) and running off the battery causing a small voltage drop. This will cause lights to dim, blowers to slow.