You are dead on about the optimas. They are really not good batteries at all. I have gone through 3 or 4 of them over the years.

To get it done, You need a higher discharge and charge battery type such as a AGM. Originally I was looking at Kinetik batteries such as http://www.kinetikaudio.com/hc1400.asp . They proved hard to find, expensive and probably come without warantee which is why i ended up with Lifelines. They can be bought across the country. I actually found them here in Seattle from fisheries supply. They use the same technology (AGM) and are substiantially less expensive. Plus they come in common sizes so you can stick them in existing battery boxes....

I have a question that may be relevent here. Are some amps able to run on less voltage than others? I recently purchased JL Audio amps that are supposed to give full power down to 11 volts. I wonder if some other amps might start cutting out at closer to 12 volts. I haven't had the chance to try these amps yet, so this is just an observation on paper. Maybe somebody like Audiofn could chime in on this.

Also, I learned through watching a buddy that your ground wires are just as important as the power wires going to these amps. Car stereo guys are used to having chassis ground close by. I know you guys posting here have good ground, but someone reading this might not realize the importance.

Only thoughts here, I know nothing.

Bill

Its funny you would mention that about ground wires because you are so right! Years ago with another boat I had made the mistake of using a small gauge wire for my ground and didnt understand why it would cut out at medium volumes (was using an 8 gauge positive wire and a 14 gauge negative).
After upgrading my ground wire to a 8 gauge the problem went away..

Presently Im running 4 gauge positive and negative wires--both are within 2 feet of the battery where they connect to the 4 farad digital capacitor and only another 2 feet until they connect to the amps--Ive learned my lesson on gauge and distance!
Im going to pickup a lifeline battery and use that as a main stereo battery with the Optima wired in series. Ill post up the results after its been tested.

Bill 3 has a very good point. When my batteries start to get low my RF power series amp is the first to cut out. The zapco's play hard all the way through. Probably just protection circuitry. Would be nice to see a write up on different amplifiers and how they perform in real world boating scenarios.

What about your ground wire to your deck??? This needs to be of suffecient size also.

Bill 3: You are correct that different amps will work at lower power. IMO on a boat you want a regulated power supply and if you can get a digital amp then you are better off then an analog one. Typically digital amps will draw a lot less. They do not sound as good but in this environment it is not as important or noticable. Amps are also rated as A,B,C..... and sometimes combinations of the above like A-B or A-D. In a boat you want amps that are extreamly efficient and ussually that means a slight loss in sound quality.

Alpine PDX amps are just what you're talking about. Thats what I use. Low power draw, low heat, compact, put out a lot of power and sound excellent.

I haven't seen many 1000W amps that take less than 4 gauge power/ground wire.

You asked about the Stinger SP1700s... I use those on most of my installs and they're great. Even have a 2-year replacement warranty if something happens.

Couldn't agree more. I have the 4.150 and 2.150 running 2 ohm and powering eight 6.5" and four 5.25" automotive MB Quarts (premium series) and they sound great.

As to the questions about some amps running better than others at lower voltages. Absolutely! I've blown up a few sub amps (one actually had a small fire) because they clipped down into the 10 - 11 volt range for a few seconds. Since then, I've been running an old MTX1500d for over 4 years on the subs and that thing has been bullet proof. I do have two computer fans blowing on it to keep it cool though.

Everything runs all day on 4 optimas with the 3.5K Westerbeke running just a 2 x 10 amp battery charger. Like others have said, I'm starting to be less satisified with the Optimas but with the little space I have they work because I stack them on top of each other on their sides under the bench. I don't know if there quality has gone down hill over the years but the two I bought last year seem weaker than the other two that I've had for 3 years (and they're not wired together in any way).

I thought for sure after 5 page someone would have suggested it, but here goes, have several people over here in the panhandle area, we play our stereos from sun up to sundown and i would have to say good wire, good ground for starters, a good charged battery, but most important, go to west marine and get one or 2 of there military 8/12 cell batterys, kinda big, but trust me will play forever and has a ton of amps, mounts nice under seat or in cabin, or even in engine area if theres enough room, but thats what our stereo shop uses and so far has not failed yet, knock on wood! worth looking at??