So here's the issue...
At night when driving with my headlights and foglights, idle at a "really" long redlight, my battery gauge drops down low.. almost too low, it gets me all paranoid.
Is this normal? I've never had fog lights before, and the battery recently just replaced due to starting /cranking troubles.

 

how low? my volts drop to about 10 at stop lights

 

I don't know how low.. the gauge doesnt have numbers on it. I'd say the quarter mark.

 

sounds normal to me cause thats about where my drops to.....1/4 from the red line

 

soo.. when you're driving around the alternator takes care of everything..
sitting idle at a light, alternator no long working.... and the battery temporarily takes over, thus the drop in voltage?

What if I let it sit idle longer than a normal period of time, would the battery eventually drain?

 

Same thing for my car, but thats from the UD pulelys. I wouldn't worry about it because you spend more time higher than idle rpms to drain your battery.

 

alt..takes over anytime the engine is running..it's when you overload the alt the battery will be used..if this is every the case then a new alt is need via the stock one is playing out or your car's needs more current to keep up with added demand or underdrive pulleys,electric fan,amps,etc either way a need alt should be on your list to buy..this would be a great time to upgrade

 

vfast is right and please give us older folks a break with the fog lights unless it's really foggy out!! the reflections from those things is murder on wet roads when you're not as young as you used to be!!! besides, the less power the alternator puts out the better gas mileage you will get!

 

dont feel bad mine does it also dropping at a stop sign.. didnt do it before although its a 2.3 4 cyl. no underdrive pulleys on this one.. so you saying the alt needs replacing although it reads fine under tests..