Battery life when playing stereo?

[Gofast]

I have 2 Interstate AGM batteries DCM0100L running my amps on the boat. Seperated with a Perko Switch ( slot 2 ). Both batteries are on slot 2, starting battery is on slot 1.

Installed April 2010. Worked great until this season. I have a Prosport12 on board chager and it gets plugged in everytime the Boat is not in use.

Sync 6 running 2 Pro 485's on tower.
Alpine PDX 6 running two 12" subs
Infinity Ref 475 running 6 in-boat speakers

Issue:

Stereo will work great for a couple of hours when anchored then the subs or tower speakers will start to cut out. If the underwaterlights are on, then I'll notice they start to flicker. Kill stereo at this point and try to start boat....dead no start juice. Switch to slot 1 and start Boat up and let it idle. Switch back to slot 2 and the stereo can run again. ( 120 amp altenator )

Have I reached the end of the life cycle for the Interstate batteries? Not sure what to do yet, researching online as well. In 2010 I could run 6 hours or more for a couple of days and still start the boat and head home. Now I get 2 hours in the 4th of July fireworks show and I have to idle the boat to run the stereo....

Thanks Rob

[EarmarkMarine]

Consumer grade batteries, even deep cycle batteries, quickly degradate when discharged below 12 volts (or 50 percent). Doing this with some repetition would show a sharp decline in battery performance after only a season. It is not a linear equation between the depth of cycle and the number of cycles. When it comes to battery weekend to weekend performance and total lifespan a good deep cycle is far more tolerant of a greater number of shallower cycles as compared with far less frequency of deeper cycles.
So begin with having enough amp/hour reserves so that you can play at rest for your required duration and still be holding at or very near 12 volts. Then make sure you have an AC charger with the amperage capacity comensurate with the depleted amp/hours per your individual usage to erase the effects of sulfation. One person may place his boat into storage with fully charged batteries and only needs a maintenance level of amperage. Another person deeply discharges his batteries and may need a 30 amp charger to effectively condition 250 collective amp/hours.
Also, I would go back to your battery and charging scheme and make certain that it is wired as it should be. If you have a switch and in the absence of an ACR/VSR then nothing but a bilge pump/float switch if applicable and perhaps a memory lead should be connected battery-direct. Everything including the starter/alternator feed, helm buss and ALL audio equipment should be connected to the dual battery switch output post.

David
Earmark Marine

[BNIROOSTER]

You could also switch to a couple golf cart batteries like the trojan t-105. You will need to use two due to the fact that they are 6v each. I have been running this setup for 2 years now with no problems. I am running a large demand system (200amps or so) and have upgraded the charging system tremendously. PM me if you are interested in knowing how I done mine.

[mcxfan]

I too have a large system installed in the boat (roughly 2600 watts) and have had no luck with the Interstate batteries. I switch to the Odyssey AGM batteries and have had no issues. My battery and charging set up is very similar to yours other then I have 3 Odyssey 2150 AGMS. 1 is dedicated to switch location 1 and the other two are wired in parallel on switch location 2. I also make sure to charge them my 50amp charger after a long weekend. I've been running Odyssey's for years now and are completely satisfied. The only drawback is price (roughly $400 each)........but as the saying goes, you get what you pay for.