Heres a setup some of you might be interested....I'm getting the dual alternator doen and second battery....on my H2...shoudl be done by end of the month...
My brother has the same setup for his Escalade...with factory battery and second optima yellow top running a 3000watt sound system and hasnt had one problem...
http://www.davesdcelectric.com/pages/1/index.htm
H2 HUMMER W/ 130-160AMP ALT............................................... ...............$675.00
DUAL AC/ALT H2 HUMMER W/ 140A ALT ..............................................$925 .00