electricity consumption

Hey There, I'm trying to build a speaker with a subwoofer of 8ohm impedance and 15watt threshold and 2x 4ohm 5w tweeters. I want to power the setup using a battery but dont know what battery to use as I dont know how to find the power consumption of the speakers. Plz Help!!

I am currently looking to buy a high performance laptop with a reasonable price tag. Therefore, I have found the ASUS G55VW and the Lenovo Y580 and was wondering which was a better buy. Here are the Specs: ASUS :- CPU - Intel Core i7 3630QM (Quad core 2.4 GHz) RAM - 8GB/12GB (not really decided...