Battery and Warranty advice

[Ravin]

Hi I have a 2003 hummer H2 and my battery just died on my. I have just under 36k so I am still under my warranty. My question is the battery covered under warranty or is it a wear and tear item? Also if I need to replace it I want to get and Optima redtop but I am concerned that it doesn't have enough CCA's. The stock battery has 880 cca's and I think the optima has like 680 cca's. Is that sufficient enough CCa's