Car loses a volt as the engine warms up..., weird one Options

[anthony]

Ok, here's the situation. When I start the car cold I get 13.2 volts across the battery terminals. Perfect, right?

As the temperature gauge moves towards the middle of the gauge I slowly loose more voltage until I'm down to 12.2 volts.

Is this normal? I'm thinking that at full operating temperature with no accessores (lights, brake lights, etc) I should have full charging voltage. It seems that something is kicking in as the engine warms up and draws a full volt.

Are there any D-Jet components that would draw voltage as the car warms up.

The voltage drop is gradual. As the temperature gauge goes up the voltage gauge drops in sync. And this is not a faulty voltage gauge issue. I've verified this with a volt meter across the battery terminals.

[davep]

I'm talking about the voltage while the car is running.

Optima actually recommends that the alternator put out 13.8 to 15 volts.

That is the point I'm trying to make. If the running voltage is lower than the not-running voltage, the alternator is not doing its job. When you turn on the ignition does the alternator light come on at all? Does it go out when the engine is running? There is a fundamental problem here. What is the battery post voltage with the engine not running? Can you charge the battery out of the car and get it up to 13.8 volts when it comes off of the charger?