Cars dead! HELP

I recently hooked up an amp (300 watts) and two 10 inch subs to my car. now my battery is dead. I was playing the system for about 15 minutes but didnt have the car running. Are you never suppose to play a system with the car off? (as the alternater cannot charge the battery)? Well my second question is I must now jump my car off some one elses, do I have to unhook my amp from the positive terminal of the battery to prevent damage to my amp, or to the fuse on the power wire? Thanks

sounds like your battery has crapped out. i would sugguest an optima yellow top. no you don't have to disconnect anything.

btw, i have played my system at full tilt for 30+ minutes with the car off without draining the battery. you can see what i have in my sig.

are you never suppose to play the system with the car not started? Are you sure I dont have to disconnect my amp before jumping the battery?

don't second guess me newb! if you ask a question don't ask whether i am sure!
j/k, yes i am sure, i have done it several times.

ok thanks BJ, I will jump it with out unhooking the amp. Thanks for the reply in my other post as well! Where can i find an optima yellow top battery and how much do they run?

http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=263-145
don't know if that is the cheapest you can find them, but i really like PE. they usually have the package delivered two days after you order.

if the car providing the jump is relatively new (90's or newer), you should turn off the car providing the jump before starting the dead car

about the optima battery what do you suggest ussing if they don't one for my car

if the car providing the jump is relatively new (90's or newer), you should turn off the car providing the jump before starting the dead car
I've never heard that before, why would you turn it off?

A really dead battery may put such a large instantaneous strain on the good car that it could drop the voltage low enough to damage the computer or other sensitive electrical components. It can't damage that stuff if the car is off.