Replaced battery, now low battery light comes on..
 

when the car has not been driven for 3 days. Drove it on the highway last night for an hour and started it today--no battery light when started.

This battery was replaced by the dealer and has a higher amp/hour rating than the OE. I suspect there must be a higher than normal battery draw on this when the car is sitting; anybody know what the stard draw on the battery is while the car is turned off?

Thanks for any help.

There has been at least one problem reported with the Nav drawing more power than it should when the car is off. Do a search and read that thread if you have Nav. The original shop manual cites 20 mA max as the dark current draw. I seem to recall that was upped a bit recently but can't remember where I read that.

Just beaaacause the battery is new doesn't mean it is charged.

You need to charge a new battery.

Perhaps your alternator is bad. Charge the battery first.

Agreed. If you only drove for brief periods after installing the new battery, it may have been undercharged. Starting will further discharge it. A long drive will charge the battery. See what happens now that you have that 1-hour highway drive under your belt. That in itself should have fully charged the battery.

Thanks for the replies--one more note
 

The battery was replaced 3 weeks ago. The car has been driven at highway speeds for atleast a half hour or more repeatedly, so prior to the car sitting for 3 days, the battery should have been fully charged.

What is at issue, is that that on a cold morning after sitting for 3 days, the car cranked slowly and the battery light came on after it was running, just like the old battery. I thought that with the new battery, the slow crank, battery light thing was goe but I guess not. My wife is due to drive it about 100 miles today and I'll let it sit after that and see if the problem occurs again.

check that your terminals are clean and tight

Also check the alternator belt tension.

It's starting to sound like your alternator is not putting out enough juice.