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  1. #1

    Default Thinking of adding a sub?

    I got an 04 XLV that I was thinking of adding a subwoofer to I am already running an amp for my 6 6.5" in cabin speakers and a kicker 450 watt amp for my tower speakers and two batteries wired in parralel will the boat charging system handle a third amp to run a sub?

  2. #2
    Join Date
    May 2009
    Location
    Dallas, TX
    Posts
    880

    Default

    That is a difficult question to answer in absolute terms without knowing how you use your system. But here are a few qualifiers that might help you.
    Certainly go with Class D on the subwoofer amplifier. And a majority of monoblock amplifiers are Class D regardless. It also makes a 60% difference in current draw as applied to fullrange amplifiers if you haven't already gone the Class D route.
    Worry less about the subwoofer power handling rating and more about the performance. The two are not necessarily tied together. A more responsive subwoofer translates to a subwoofer drawing less power and that will help your cause. Bass-reflex will also increase efficiency, so greater output means the need for less power and less current draw. And that only costs you a bit more wood.
    When evaluating your charging system, the audio system draw may be secondary to how far you discharge your stereo battery bank. Never discharging below 11.8 volts minimum (no lower than 12.0 volts is a good minimum target) helps the batteries and helps your alternator. Also, do not push the batteries beyond a healthy state. When it's time to replace the batteries, do so. Exhausted batteries are brutal to an alternator.
    If you have accidently depleted the stereo bank below 11.8 volts, then give the music a temporary rest while burning some gas. Don't try to run the boat operations, drive the stereo system hard, and recharge several seriously deeply cycled batteries simultaneously.
    If you play music at rest for an extended period then you really need to supplement the boat's charging system with a SMART AC shore charger of the correct capacity that corresponds to the size and typical depeletion level of your stereo battery bank.
    10 fully charged batteries are not a load on the alternator. Several deeply discharged batteries can represent a load greater than your audio system!
    Per the above, if you do all the right things, rarely do you have to upgrade the alternator for a system with less than 2500 watts RMS. Music is transient in nature, so you are drawing less current than most think, unless the system is tuned poorly or driven into compression.

    David

  3. #3
    Join Date
    Oct 2010
    Location
    Lake Wylie NC Area
    Posts
    774

    Default

    Trever,

    The answer to your question is kind of relative to a few things. One thing you can count is, is that any standard alternator will not do a good job, as its not designed to, recharge a depleted house battery bank. With the engine running, you should not experience any issues with the alternator keeping pace with the system, but if you spend a great deal of time running the system while at anchor, a larger battery bank is a plus and you will become more dependent on shore charging.

    Im guessing you have a main cranking battery and then the 2 batteries in parallel are the house battery? Are these banks isolated by a dual-battery switch?

  4. #4

    Default

    Sorry for the delay been working. I typically just play in cabin speakers on the beach I have tower speakers wired into acc. switch. I have 2 batteries total they are wired in parralel so no switch or dedicated accessory batt. I will remedy this issue soon.I plug these batteries into a battery tender when boat is out of water. I had a kicker zxm450.2 running my tower speakers and a 4 channel alpine running in cabins Kicker amp went bad and HIFI sound connection didn't have a replacement so they gave me an in store credit so I was thinking about getting a 5 channel amp to run in cabins and sub and still use a 4 channel Alpine amp I already have in the boat to run my Kicker tower speakers. Would this be a better option than running 3 separate amps in the boat (sub, in cabins. towers)?

  5. #5
    Join Date
    Oct 2010
    Location
    Lake Wylie NC Area
    Posts
    774

    Default

    Adding a dual-battery switch and a cranking battery, leaving the current 2 wired in parallel as is for the house bank, is a good plan.

    Would this be a better option than running 3 separate amps in the boat (sub, in cabins. towers)?
    From what aspect?
    Cost - a 5 chnl amp to run in-boats and a sub can sometimes be less expensive then a 4 chnl and a mono of equal wattage.
    space - do you have room for 3 amp? 3 Class-D amps can take up less space then a 5 chnl and 4 chnl Class-A/B.
    Battery consumption - this is really based on the watts output, not the number of amps needed to achieve that output. 2 amps putting out 2000W rms can consume the same battery Ah as 3 with the same output.

    I see nothing wrong with moving the existing 4 chnl over to drive the towers, but without knowing some specifics, I cant say of there would be an increase or decrease in the performance. May not be a change even.

  6. #6
    Join Date
    May 2009
    Location
    Dallas, TX
    Posts
    880

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    As long as the subwoofer choice is well matched to the power of the in-boat amplifier's sub channel, a single amplifier chassis to run all in-boat speakers including the subwoofer is fine. The only instance where you really need to separate these two chassis is when your demand for power is large enough that it exceeds the capacity of a single-chassis, multi-channel amplifier. And with today's many large 5-channel amplifier options, that would have to be some really big power.

    As you have already indicated your plans, you must separate the starting battery from the stereo battery/bank with an isolation switch in one form or another (whether manual or automatic).

    If you are cycling your batteries really deep then a battery tender/maintainer/trickle/minder type charger isn't going to cut it for maximum battery longevity. Those are fine for maintenance in applications where the vehicle or craft is placed into storage with batteries already at a full charge.

    When at rest, at the beach or otherwise, and you are listening to the system outside and away from the boat, the in-boat speakers (within the bathtub so to speak) plus their driving amplifier will have to work inordinately hard to project the sound at any range away from the boat and down at water level. It also tends to suck an inordinate amount of current and pulls your battery(s) down much faster. So try to leave this role to the elevated and directional tower speakers and turn the in-boats off to promote longer playtime and preserve batteries.

    David

  7. #7
    Join Date
    Oct 2009
    Location
    Pacific NW USA
    Posts
    505

    Default To be... or not to be... A bass machine.

    Think the Op needs to answer his own question on the battery situation. Everything in this thread is for the most part is speculative academics without knowing model numbers and such. What really needs to be asked is, "How hard are you going to run your system. " And how long do you want it to play... As an example, I was on a boat this weekend with a class AB tower amp powering 4 speakers, class D cabin / sub amp powering 6 cabins and a sub...

    He had two stock batteries and played for almost 4 hours at moderate volumes without needing to charge the batteries. That figure can go way up or way down depending on the music volume and even types of music being played. In your particular situation - adding a subwoofer is by definition going to become a major user of battery current. With that said, It's a great idea to add a sub for one primary reason: You'll gain almost a full octave of musical information that your not presently hearing in your current configuration. You don't have to be a bass head to enjoy the bottom end musical extension that a subwoofer will add.

    In all light heartedness, you need to step in front of the mirror and ask your self, "Do I want to be play harder, longer and louder..." than this scenario mentioned above. If the answer is yes, start investing in charging and bigger battery banks and a mean looking subwoofer. Several of the guys in this forum are in that category. Several are not.

    -Brian

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