my car battery died yesterday night.., what happend? Options

[yellowxboy]

yesterday night i was out with my gf .. after dinner we went back to her place to take a nap and when we decided to go out for some coffee, my car wouldn't start. all the lights were very dim, my guages didn't light up, it made a faint clicking noise when i tried turning the key but the motor didnt even move.

at first i assumed the battery died, but i just bought the battery not too long ago (5 months i think). my friends came over to jump start my car and everything is back to normal. my gf's dad thinks that the alternator is old and that i need to buy a new one because it is draining my battery..

any suggestions? i want to get a general idea before i bring it to a machanic to get it fixed.

[ i didnt leave anything on while my car was parked, i have 2 subs that are powered by a 900 watt amp, i rarely turn on my glow lights. but i do drive with my lights on in the morning.. could that be a reason why it drains? ]

[yellowxboy]

wow, thanks for the help guys. i ended up going to Autozones to get a new replacement battery cuz i still had the warrenty, the guy checked out my alternator and ran the tests.. my car put out 50 watts on idle, he said normal is 80 so my car's alernator is fine. he said that something was draining my battery, we checked my subs and it wasnt draining it. he said taht if it was the subs, then my battery would've died in 3 months not 11 months. so yeah *shurgs*

where did you get the test from?