Battery Drain

I'm looking for some tips or obvious things to look for in my situation. I have a 93 LX and the battery keeps going dead on me. I thought it was just the puny stock alternator not keeping a charge on the battery, but I can hook up my battery charger and put a full charge on it and two days later it is completely dead. The only thing I can think of is, before I bought it, someone put in a triple cluster in the center vent and there is a battery gauge that seems to run straight off of the battery. I know certain things like the computer and radio memory use constant voltage to retain their memory, but would this gauge be enough to kill the battery after a couple of days? I've also noticed a hard start situation, but I'm assuming this is related to the battery issue also, where I'll turn the key to start and the motor turns over slowly at first and then faster a couple of time then starts. Maybe it just a crappy battery. What does everyone think?

I'll have to check the vanity lights... I thought at first it was the latch for the hatch cause I didn't close the hatch all the way one night and killed the battery myself, but since then, I've checked that and that's not it. To answer crjpony, yes, it is a volts gauge and it reads whether the key is on or not. I am in process of moving the gauge senders back to the cluster (the guy disconnected the oil and temp cluster gauges to put them in the center vent plus a voltage gauge in the center vent), so hopefully that will clear up the problem.

I do have a new 3g alternator that is going in soon, I would like to just figure this out before I install it.