Cranking vs Deep / Crank combo

Does anybody have any input on wheter or not the combination cranking/deep cell battery is a good or bad idea. No big sound systems on board, just the stock clarion radio/tape player. It seems like the best of both worlds in theory.

The deep cycle battery won't have more Cold Cranking Amps (CCA) than a regular battery. Deep cycle batteries are made for continuous low amperage drain over a long period of time i.e. stereo, trolling, motor, electronics. A Cranking motor i.e. starter, needs high amperage for a short period of time that you may not get with a deep cycle battery. If the deep cyccle is rated at or above 650 CCA then your good to go, most deep cycles are 550 or less. Me personally I have a group 31 cranking battery rated at 950 CCA and don't have a problem running the radio and 1000w amp all day.

Thanks. I have a slippery grasp on the concept of straight cranking and straight deep cell batteries, but don't know much more about the combination batteries -- other than how to spell it. I have seen the combination batteries for sell but have never known anyone who used one. Currently I have a cranking battery with 650 MCA and wondered if the marine combo battery would be worth the expense vs an automotive high CCA battery like 79nautique.