I got some good info from searching, but had a couple more specific questions. I have a 21' Chaparral with a 5.7L mercruiser. Current battery is dead.<br /><br />For next couple weeks/month I want a battery that will start my boat reliably. The only thing I might run with the engine off is the radio, but I dont have to do that. I would rather make sure I get my boat started rather than listen to music. <br /><br />Eventually (sooner than later) I want a dual setup, using the standard 1,2,both,off switch (like you find at Bass-Pro). I will be using the radio with this setup - mainly, I want to ensure that I get home after being out on the water for the day.<br /><br />So I guess my questions are, what batteries do I need?<br /><br />A. #1 dual purpose, #2 deep cycle<br />B. #1 dual purpose, #2 dual purpose<br />C. #1 starting only #2 dual purpose<br />D. #1 starting only #2 deep cycle<br /><br />Also, what brand - it seems like many people have success with the Everstart Marine Maxx - but which one do I need?<br /><br />Thanks