Oldsmobile/Buick Repair: Battery et al, amp meter, specific gravity

Question
Okay - my girlfriend left the dome light on and killed the battery.  I charged it and it started - but then the battery died again.
I've just charged it for 4 hours, then it did not start. I put the charger back on, and the amp meter maxed out - so heavy a draw in fact that the charger overdraw disconnect kicked in.  
I don't have lights on or anything like that, and the battery produces no spark when hooking up cables (doesn't seem like the battery has a short)
It's a side-post battery and I don't have another one at the minute.
I've cleaned the terminals - what could be creating such a draw?
Thanks
Jess

Answer
hi jess ,,.when you completely discharge the batt it is possible to reverse the polarity.batterry,s are measured in specific gravity when you completely discharge the specific gravity goes out of this world .this creates a dead short.the batt is junk jess you have to get another. good luck.please take a min to rate our service   billymac