See this is why I ask these questions.... to get honest opinions which is awesome thanks! What do you all think average runtime of a 250w amp and hu would last off a plain interstate battery single deep cell? before I could go hours with it turn to a soft rocking decibel, I just don't want to get stuck out on the sand bar after laying around for a few hours relaxing and do the humiliating call for a tow by the pontoon!!!! The more I think about batteries in the rear lockers the mroe i think it would be better hidden under seats somewhere. I do like the idea of up in the bow since that is sort of wasted space on the one side.
Okay, how long of a run time with a standard group 24 deep cycle battery with a 250 watt ampliifer?
It can vary by a large degree. Lets say you have a lead acid deep cycle battery with 65 amp/hours.
Is the battery in new condition and fully charged?
Is the amplifier Class AB, G/H or D? It can make for a 60 percent swing.
What load is the amplifier running? The lower the load including bridging the greater the current draw.
Is it just below full volume so the amplifier isn't clipping? Backing off wide open just a bit could double the playtime.
What kind of music? A steady and heavy bass beat or softer stuff? Bass will draw a little more.
How are the tone controls, bass boost or EQ set? Crossover settings and system set-up can make a pretty big difference.
You should get at least a solid two hours play time, just a rough estimate, and perhaps double that if the music is at conversation levels.
Keep in mind that the deeper you cycle a battery (even a deep cycle battery) the fewer cycles you will get. So a little more battery capacity can save you in the long run as long as you have a good restoration/charging plan. Sometimes the alternator is not enough.