Severe battery drain

Replaced new batter multiple times and battery is drained to the point the car wont start after just a few days. Issue started with corrosion on both terminals to the point negative terminal connector needed replacement because it cracked. Cut connector off both positive and negative and replaced them. Replaced the battery multiple times and still drained. Replaced the alternator thinking that was the issued and replaced the battery. Battery died less than a week. Replaced battery and began unhooking connections when car was parked. Checked fuses and found the fuse for the cigarette lighter was blown. Replaced fuse. Was driving the car and rolled drivers window down. Noticed the battery gauge was draining quickly draining to the point drove three blocks and battery was dead. Car would not restart. Replaced battery again and began unhooking terminals when car was parked, thinking there was a parasitic drain when car was turned off. Battery still died after a few days. Alternator does not appear to be charging battery correctly. Thinking it may be the battery cables or ignition switch. Planning to get the wires replaced as they may be faulty and corroded, but would like to know if there may be another cause I haven't considered yet.