battery question

In my boat I have 2 amps, 2 12inch subs, 4 mb quarts tower speakers, 4 speakers inside the boat. I have one battery for the audio system and one for everything else. So my question is hows does my audio system battery die so much I have to charge it every 3-4 outings. Both of them are deep cycle. It seems weird to me 'cause I have a system in my car just like the one in my boat(well close enough) and the battery has never been a prob like this?? Any advice would help!!

DO you change between the two when using? Do you leave the stereo one connected when starting the boat?


If not, then it never gets recharged. By changing back to the starting battery, your stereo battery is not getting charged. So whenever you are just playing the stereo, it is constantly getting drained.

Or, I could be totally wrong, but your charging regime needs to be looked at in order to help diagnose the issue.

Tell us how you are charging the batteries.

Battery switch?
Battery combiner?
Diode battery isolator?

If you are taking power out of the battery you have to put it back in.


You said it dies every 3-4 outings. Is an "outing" a weekend, or is it a run? If the battery dies after 3 or 4 days of use then I would say you have some issue with the battery draining while it is sitting. Is the amp getting shut off with the stereo? Do you have any other equipment hooked to the battery? (alarm, bilge pump, cooling fans, etc)