Battery running dead!!!!!

Hello all.
I have a simple question. My car sat at the airport for a bit more than a week and had been sitting for a week or so before that. The battery is old and has run down from sitting too long. On the way home the dash lignt came on indicating a bad charging system. So, the alternator is new, the computer is a one year old rebuilt. No obvious wire problems, though one of them was a bit freyed and I spliced it out. The question is, will a bad battery cause the car to not run? I know that on older cars you could just take the battery right out and it would keep running. But would a bad battery cause this sort of malfunction? The car runs until the battery dies. If someone can answer this I will be happy.
It is a 95 3.5 intrepid.

thanks

ps. I charged the battery all night it read 12.67 volts afterwords, but when I turned on the lights it dropped to 12.05 does that indicate a bad battery? The instructions on the alternator said it might.
Jacuzzo

i had the same problem, 12.67 volts is not enough to do anything with. it need to be about 13.50 volts. what you will need to do is either replace the battery or go to a local automotive store and pick up some sulfuric acid (http://www.google.com/search?hl=en&client=firefox-a&rls=org.mozilla:en-US:official&hs=swF&sa=X&oi=spell&resnum=0&ct=result&cd=1&q=sulfuric+acid&spell=1). then just add the acid to the battery.

1 of 2 things has happened. 1. the battery has been watered down so much thats its hard for it to keep a charge. or 2 the sulfuric acid has eaten away at the plates.

if its a water problem then just drain some of the fluid out, and add the acid and put it on the charger.
but if the plate is bad, you'll have to replace the battery.

hope this helps

Terrell