I have been ask a few very common questions, so I figured I would just post some of them up. If you have any questions post them up. I will answer them or find the answer for you. CCA is the maximum amperes that can be continuously removed from a battery for 30 seconds at 0°F before its voltage drops to unusable levels. A 550 CCA battery can supply 550 amperes for 30 seconds at 0°F. This was important back in the days when vehicles took a long time to start. Now if you put a charge to your starter for 30 seconds it would probably burn up, and it doesn't make any difference in car audio. CCA is the same test as above but at 32°F. AMP-HOUR RATING is a unit of measurement for battery capacity, obtained by multiplying a current flow in amperes by the time in hours of discharge. (Example: A battery which delivers 5 amperes for 20 hours delivers 5 amperes times 20 hours, or 100 ampere-hours.) So, unless you are running a system that has a low amperage pull for hours this rating is useless. Deep Cycle Batteries/Cranking Batteries: Flooded batteries use the Deep Cycle info a lot and with some battery companies and types of batteries you have to buy a separate battery for starting. With XS Power our batteries can be used as starting batteries or as secondary batteries. Our batteries are engineered with advanced technology that gives the batteries the ability to be used as a starting battery and as a deep cycle battery.