(T) Car battery Dead

last night i went to start me car and it was dead there was ignition lights but engine wouldnt turn over.
I roll started it and it drove ok. i drove about 10-15mins stopped then did same trip back. (no problem starting)
Went to start this morning and it was a dead again.. and it was harder to roll start it.
Im thinking that the battery didnt fully charge on the first run i did last night so i drove about 40miles got home and checked the voltage and it was charging at 13.9v

Any idea what could be drainin the battery? ive noticed theres no light on in my boot could it be that which is draining my battery over night?

Ive just put a new alternator belt on and not noticed any difference in the voltage. all the earths seem ok too.
Anything else i can check?

Terminals clean? If it won't start try the single jump lead trick. If not then something is draining or the alternator

whats the jump start trick? is that were i use positive only?

No, single jump lead from the negative on the battery to the engine block!

ok ill try that when i next start up the car.. atm ive taken the battery terminal off to see if its the battery not holding its charge.. but this morning when i checked the voltage it was down to 6v. Im thinkin it could be something draining. but i wouldnt know what since ive not put/taken anything on/off.

Could just be the battery seen the last of its days then

well it is supposed to be a new battery well.. someone for like a week had it and they drained it. then it was recharged then given to me. I did have a similar problem with my old battery which is why i purchased a new one

lol ye u got a drain somewhere then! Or the alternator faulty

i just checked battery was on 12.6V stand alone i plugged battery back on and switched ignition on and with stereo and it dropped to 12.36v is that a normal voltage to be at?

if the alternator is faulty.. what test can i carry out on it?

I think 14v when the car is running, not sure

i get just under 14v 13.97 - 13.99 (on idle) when revving it goes up too 14.07

sounds fine, something must be faulty and draining power

ok.. ive dissconnected my alarm just incase it is that.. gonna see what its like later.
What other test can i carry out to check drainage? i know about the ammeter but ive not got one.. only multi meter.

Thanks for your replies btw

Faulty starters have been known to drain alot of power, not sure how to test though, sorry