Battery Suggestions

I am having amplifier over heating issues which i believe are caused by not enough power due to not enough batteries and lack of an onboard charger. I was wondering what I need. I have a 2008 Mobius LSV with an all exile system, harpoon with 2 pair of sxt65qs, 800.4 with the exile cabins, and 600.1 with an exile sub. since all amps are doing this and they all started at the same time after a party cove jam session i am pretty convinced it is battery related. I am looking at getting three new batteries (1 starting, 2 stereo). I want maintenance free because i dont want to have to add water all the time so this is what i was looking at. Note all batteries are Bass Pro Shop store brand and AGM.

for the starting battery i was looking at a dual purpose with 120 min reserve capacity at 25 amps, 69 amp hours, 55 amp hours, and 860 cc

for the two stereo batteries i was looking at a deep cycle with 140 min reserve capacity at 25 amps, 79 amp hours, and 660 cca.

would this be sufficient to jam at 50-75% volume for 2 hours with the engine off?

also will be adding an onboard charge, probably prosport 20 plus

The 20 amp ProSport is a little undersized for over 200 amp/hours. I would step up to a 30 amp given the way you will be using your batteries. This would also allow you to step up to a group 29 or 31 that should provide around 100 amp/hours each for a minimal investment. A bigger battery will translate to shallower cycles and longer battery lifiespan. A 3-bank charger in this case provides zero benefit over a 2-bank charger although it won't hurt anything.

David
Earmark Marine

You will pay through the nose for an AGM battery with enough AH capacity to do you any good vs. an adequate wet cell battery with 100+ AH of capacity. AGM batteries are worthless IMO unless you need to lay them on their sides due to space issues.

I run 4 6v golf cart batteries (interstate u2300 242 ah each) separated on 2 different banks with a battery switch between them. I've got 5100 watts rms all Exile. xi2500.1 at 1 ohm to big 15' sub, harpoon at 2 ohms to 4 sxt65Q tower speakers, 800.4 bridged to 2 Xm7's on the tower, and a 800.4 at 2 ohms running 8 exile inboat speakers.

With my "highly inefficient" exile amplifiers I went from 11am-8pm on one battery bank averaging 2/3 volume all day with the boat off. I did not switch over to the other battery bank at any time during the day, and the boat still started when we headed in that night. Anyone that was at the surf comp tie up on Lake Sammamish was witness to this. I take very good care of the batteries though with an automatic battery watering system and onboard charger that is plugged in at all times when I'm not on the water.

Other great wet cell batteries are group 29 or 31 batteries (same size).

See that's the thing about the Nu Bu experience described above. If we interpret "2/3 volume" as a 10 dB reduction then the system still plays loud at 10 percent of its full power potential. With the actual rms power and 240 amp/hours of reserves the system could play under those conditions for 10 hours. With pure Class D and the higher switching speed version of Class D as compared to Class AB the system could play 60 percent longer. Plus its fair to assume that Nu Bu's system is tuned well and that alone can double the play time at rest as compared to a poorly tuned system. People who play their system at the threshold of clipping or beyond might only get a fraction of that play time...and yet the difference in percieved volume may not be that great. Those that do not have the proper shore charging think their batteries are fully charged by the alternator and they are generally mistaken about this. And when the batteries do not receive the best of care those initial amp/hour ratings quickly diminish. 6 months or one season later you may be dealing with completely different battery performance. Alot of the above explains why different boaters have entirely contrasting experiences with their batteries.

David
Earmark Marine

David, does anyone make a 30 amp two bank charger?

rd,
That would be rare, but if the charger is 'distribute-on-demand' then it will function as a 2-bank charger in every respect and deliver its full capacity to the bank in need. You can see the Intelli-Power 30 amp on our site which we like. Intelli-Power, Xantrex, ProMariner ProTech series and Dual Pro should all make a high quality 30 amp model.

David
Earmark Marine