Best amp for 2 JL 13’’ subs in boat

I'm installing a new sound system in my 28' Nordic ('Heat' closed bow) powerboat.   I've purchased two of the JL Audio 13" W7 subs.  I want to install one on each side of the engine compartment (102" beam) because there's plenty of room & locating them on each side of the engine gets them out of the way and less chance to get wet.  I have several amplifiers on hand and have questions on which amps would be best to hook up to these.  I have just purchased a US Amps VLX-400 used on E-Bay.  I also have a JL Audio 1000/1, MMATS 1400.2, two US Amps 1000 and 1000X.  I have to be concerned about the drain on my electrical system because there are also 3 US Amps vacuum tube amps (TU-600) running the 5.1 Dolby Digital/dts sound throughout the boat.   I have added a 150 Amp alternator and two banks of two/each batteries.  All 4 batteries are Stinger SP1700 (1700 amp batts).  Would I be able to drive the JL 13" subs using the VLX-400 or would I end up stranded out on the lake with dead batteries?  I know I need a larger alternator or piggyback a 2nd, but I don't want to lose the horsepower of my 496 MAG HO engine.  The 150 Amp alternator uses 5 hp more than factory alternator already. I have a Stinger 5 farad cap and 2 Alumapro 15 farad caps that I can install also.  Any suggestions?  Am I putting too much drain on the elec system?  Thanks for any suggestions you might have.  ___________________________________________ waterskiers2 rockin the river!

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waterskiers2
rockin the river!

Well since I had to start a new topic, I might as well complete the description of the A/V system installed in my boat.  My boat is one of the featured boats in the June issue of 'Hot Boat' magazine (pgs 66 - 68).  I've made quite a few changes to the boat since purchasing it last summer but the pictures of the boat will give you an idea of what I've had done so far.  The video system is inside the motorized fiberglass door by the c**kpit.  It closes off the opposing love seats from the rest of the boat.  I've also added more indirect lighting (neon & LED) to the interior & engine compartment area. 

The A/V system is comprised of a marine head unit: Clarion XMD3 (AM/FM/CD/Sirius/Ce-Net controller), Clarion DVH940 Dolby Dig/dts processor, DVC920 sound processor controller, Sony DVX100 (10-disk DVD changer),  Sony 20" monitor, 2 pairs of Focal 165W component spkrs, 1 pr MQ Quart NKD116 6.5" coax, 1 pr MB Quart NKA169 6x9 coax, five Bohlender-Graebener 8" ribbon midrange (for 5.1 interior spkrs), 5 6.5" carbon fiber woofers, 5 1" spiral ribbon tweeters and 2 JL Audio 13.5" W7 subs.  Powered by 3 US Amps TU-600 2-channel vacuum tube amplifiers powering the interior & exterior spkrs.   The subwoofer amplifiers is what I'm having trouble with both deciding due to power limitations & overall sound quality. 

I have the subwoofer amplifiers in my previous post available, but when I've tested the system sitting in the drive, the batteries just die within 30 minutes.  I know I've exceeded the elec capacity of the boat, but how can I get around this?  I've installed the four Stinger 1700 amp batteries and the bigger alternator, but I want to be able to park the boat in the channel for 4-6 hrs & still have enough power to start & get home.  I realize the battery life is going to be really short due to constant draining & recharging, but I can live with that.  I just don't want to get stuck 50 miles from the boat launch.

Any ideas for auxillary power?  Just keep adding more batteries?  Can I use cheap batteries rather than the Stingers?  Would I be better off with 10 cheap batteries than 1 expensive Stinger?  This area of 12 volt isn't my forte & the installers around here just want to sell me custom alternator configurations.

Any suggestions would be appreciated.

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waterskiers2
rockin the river!

wow.

in order to make the system last longer without a charge i can only think of adding more capacity to the system. bigger larger batteries. do you currently have your system charging from the alt. or of shore power during the nights? if the second add a few more batteries and be done with it.

if you are charging off the boats elec. maybe  you could seperate the boats electrical from your a/v system. putting your stock alternator back on and putting it with the complete stock electric system of the boat battery and all. then putting your new 150 amp alt on the engine piggbacked connected to a "2nd" electrical system that would be for your a/v system only.

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Quad L Handyman services

Ah. and as the the sub and amp system i have a feeling you are going to run into nothing but more problems no matter the setup
(amp/subs) you use.

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Quad L Handyman services

The batteries are charged with a 50 amp charger in the evenings.  I basically 'hold my own' when cruising @ 3000 rpm with the sound system running.  The Stinger 1700 amp batteries each take 4 hours to recharge with a 50 amp charger.  There are 4 Stinger 1700 amp batteries right now.  I have 2 in each bank.  The battery isolator keeps the 2 batteries for starting/navigation lights from draining but the other 2 batteries exclusively for the sound system are dying after about 45 minutes.  Bass starts distorting, etc and I know it will blow the amps if I keep running @ low voltage like that.

The solution would be a Kohler marine generator but then I'd have the sound from the generator (not to mention the exhaust) while parked. 

I know there are a lot of 'bright' people that browse these forums and I'm hoping someone has an idea that I haven't heard yet. 

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waterskiers2
rockin the river!

Yea, I was going to suggest an APU like the Kohler generator.  More batteries can work, of course, but you will soon reach the point of diminishing returns, with too much weight that can throw your beam off.  Do yu keep your boat engine running?  Look into a high-capacity alternator if so.  If not, APU is the only thing that will work.

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I shut down the engine when parked because of the thru-hull exhaust.  Even on 'Silent' mode it's about 95 db.  The 150 amp alternator is the high-capacity alternator.  The standard Mercruiser alternator is only 68 or 78 amps depending on engine.  I have the serpentine belt, allowing me to go up to a 150 amp alternator, but everyone's telling me I'll have problems either piggybacking or installing higher than 150 amp alternator.

I've seen the 200 & 300 amp alternators they use for welding and was almost talked into buying one but then the mechanics tell me I'll be replacing either belts or pulleys every week. 

I'm stumped & out a lot of cash!

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waterskiers2
rockin the river!

Your best bet is going to be to find a "Marine" Generator, I'm pretty sure that you could find a quiet one.

Just do your research and talk to a few people.

Onan.com comes to mind

 

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Serving the country, one coffee at a time.
USAF!

the alternator you have will barely power one of the subs at its optimum performance. high output alternators get really expensive after 150 amps. i would piggyback another one and use that one just for the subs. jl 13.5" will need the 1000/1 class d from jl. thats 1000watts rms= 3000 peak. then i would get another battery for the system setup and youll need .5 farads for every 500 watts youre pushing.

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always looking for new info and willing to give it

You don't really need caps....

well it helps. instead of reaching all the way to the battery for power when you have a voltage drop, the caps are right there with the help.

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always looking for new info and willing to give it

Caps won't help.  They are not a power source.  Indeed, they will only drain your batteries faster without a generator present to supply the power.  The only thing you can do is increase your battery bank size or get that APU.

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getting more batteries wont give you any improvement over a couple caps if you dont get the alternator. caps are just as much a power source as a battery. if you cant power either, than either is useless.

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always looking for new info and willing to give it

Sorry mikedawg, you're wrong.  Caps are not a power source, they are transient filters.  They place additional load on the electrical system since their storage capacity is so small and they must recharge (from the battereis or generator) every time they cycle.  They can help an amplifier sustain peak output during small and short duration power cycles, but they do NOT supply power unto themselves.  In a battery-power-only situation like is being described, caps are actually a bad idea and will do more harm than good.  More batteries and deeper cycle batteries are the only solution if adding a generator is not possible, and then these will have to be recharged after a few hours of operation.

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so whats your guess of how many batteries he will have to get to be able to have 2 13.5 jl subs. my thought is at least 10 to listen comfortably before the next overnight charge. i have one 13.5 with two  svr dry cell audio batteries and i cant listen to it for more than 10 seconds without having to jump my car. and thats only with a one farad cap.

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always looking for new info and willing to give it

The person who started this topic reports he is getting 30 to 45 minutes of operation with 4 batteries now.  He wants to get enough capacity to sustain 4 hours (or about an 8X increase.)  In my opinion, it is insane to try and do this on battery power alone.  An APU generator is the only answer and will be 1/10th the price of a 32 battery array and 1/100th the weight.

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lol i hear ya. that damn sub drains power like none ive seen before. i saw a test where they put as much power to it as they could and sustained for over 8 hours. the sub took and finally they just gave up. so the power handling rating for that sub is an extreme understatement.

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always looking for new info and willing to give it