is it possible to hook up two amps at the same time? Im planning on hooking up a 300 watt amp for two 6x9's that i have put in enclosures and one 800 watt amp for a sub... will this be ok for the battery or will i need a stronger batter?

 

Is it possible... yes...

The alternator realistically probably can not supply more then a spare 50 amps which equates to 600 - 700 watts...

Now since you wont be driving the sub at full load all the time this seems reasonable but you could always add a cap to it for large notes but a cap just is a bandaid...

I'm sure a yellow top with a cap can take this load just fine...
You could always benefit from a HO Alt but at that level I would probably not

 

Why on Earth would you be trying to cram 300W into 2 lowly 6x9's? Is there even a set of 6x9's on the market that can take 300W RMS?

 

No, but I doubt any of these numbers are RMS, which makes this all feasible with little to no change in the charging system.

 

yea none of that was RMS.... is there a stronger alternator that i could buy maybe because my car has trouble starting usually anyways... whats the price on one?