Not being condescending, but just open the hood and take a look see.
Battery size should be listed in a catalogue where you buy it. That's a top POST battery , terminals are a standard size, one is larger than the other, are you sure you are not trying to hook up bacwards - NOT A GOOD THING!
I don't know the answer, but I wanted to comment for those that might not know, this is a side post battery (I assume... I have a '94 which is a side post)
Raise the hood on your 2000 Buick and look see.
12 volt. side post
Positive (Red) to positive post on battery. Negative (Black) to negative post on battery.
under the back rear seat. Make sure to put protective caps back on battery post to prevent shorting out on back seat railings.
The ground strap is the battery cable that connects from the negative battery post to ground, usually the chassis.
You have an open connection from the large alternator output post to the starter main battery post or fuses blown or circuits open feeding the alternator control wiring.
No. If the battery post if missing then you will have to buy a new battery. My question to you is how is a battery post missing?
On the same post connected to the battery.
You just pop up the back s.eat and there it is. Side post 8mm socket/ratchet
You can buy an adapter to convert a side post to top post or visa versa.