bpounds, thanks for the clarification. I always thought the 24VDC was for more CCA's, but now I know. I'll have to check the application and availability of Interstate. BUt when kids watch DVD's for a while, I can relax knowing the Optima can run dead 350 times before ruined. My wife's minivan battery died everytime the kids watched dvd's for an hour. I installed a blue optima, and they can watch for many hours, and it will still start the car in a crunch. I just wanted to see what people like for the SD. And I think my gut feeling to go with the cheaper priced Costco Blue is winning over.

Your clear on the math. Both Red and Blue's are the same CCA's, but the Blues are also Deep Cycle (Red top is a starter only), and can discharge 350x without warping the plates. Standard lead/acid's can discharge 100% 2-3x and then the plates warp and the battery is toast (with experience and what I read).

The RED = 36 month warrantee
The Blue = 24 month warrantee
The Yellow = 36 month warrantee

It looks like the Yellow's are the best for this application, but 2 = $360, while I can get 2 Blue's for $240.

I'm ready to install my new 1200W 5 channel amp (& whole system/headunit/nav/speakers) so I like the thought of.... and have a good history with.... the Blue tops.