Huge battery drain issue

[longblue72]

Just recently I've started to have a big drain of my battery. I'll say this first, its a brand new battery, I've went through three alternators. ( two were remanufactored incorrectly from advanced and one is a one wire) thinking that my alternator wasnt doing its job. But the one wire is and with a DVOM it shows the battery charging around 13.5 volts.

My main Question to try and solve this battery drain issue is what have you guys found that gave you this problem? Is there something that seems to keep coming up with everyone? Things to check first? Any help is greatly appreciated because this is my daily, and its really frustrating having the battery be stone cold dead after one day of work each day.