You cannot wire two 12 volt batteries in series and end up with 12V, you end up with 24V, it will burn up all sorts of shit...

You have to put them in parallel, also CCA is irrelivent when you talk about a stereo system, you need to know the amp hours they have.

Not trying to be a snot, but the stereo has to run on one battery and the engine on another, if that were true you would never have a dead battery...

I would recommend a battery switch and an isolator, that way you could run the stereo until the battery was dead and the engine battery would be able to start the engine, I would recommend a little less stereo and more boating to keep the batteries charged 

A stereo will kill the batteries in about 15 minutes with any volume whatsoever....

GT

they are ran parallel , my bad i wasnt making a welder lol. Yeah thats what i figured a switch an a isolator . Anybody reccomend  a good battery?

Nothing wrong with the batteries you have I wouldn't think, I just run some NAPA POS and it's 5 seasons old.

GT

Maybe a cap would help on your battery issues too...I could be wrong I'm not a huge stereo guy...I listen to the big block band most of the time! Or i sing myself!

Which reminds me Josh, take the baffles out.

Ray

Deep cycle battery/batteries for stereo. Regular starting battery (marine type) for starting and running the boat.