Help installing Amp and Subwoofer (battery wiring)

[bird391]

I'll start off by saying that I am by no means a stereo/audio expert. I would say I'm a hobbyist when it comes to wiring stereos and electrical circuitry. I want to hook up an amp and subwoofer in my boat. I wanna hook up a second battery that solely runs the amp by ityself as well.

Here is my setup - 1978 Lund Boats 17 Sirius BR, 1989 Evinrude 140HP E140TXCE, I am currently running everything (starting, stereo, bilge pump, livewell, (no trolling motor), and lights. The amp is a 1000 watt 4 channel amp (not a marine amp) but I will only be running 2 channels bridged to 500 watts peak power, not sure of the RMS. The sub is a cheap old PLYE sub with a 350 RMS rating. It sounded alright in my Durango so I figure it will be fine for my boat. Im not looking to shake to the ground with it, I just want some decent sound. Money is a little tight these day with gas being $4.00 a gallon so try to keep that in mind.

my questions are...

1. Should I wire one battery to the other battery or should I just leave it separate from the rest of the system and WHY?
2. If I should connect the batteries together what would be the proper wiring and WHY?
3. If I should run it separately what is my best wiring options and WHY?
4. What type of battery should I buy and WHY? I'm thinking deep cycle.
5. Would a capacitor help and in what way does it help in a marine setup?
6. If I do run the batteries hooked together will my motor change both batteries?
7. How does the charging system on an outboard motor work?
8. Should I consider an onboard charging system?

If there is anything I have missed by all means please feel free to comment or give advice. Also please for all you extreme experts out there I don't need to hear that I should get a marine amp, or that what I'm doing is stupid or unnecessary. I'm using the equipment I have because its stuff I already have laying around the house, and as far as you folks out there who think putting a loud stereo system on a boat is pointless or bothersome to other people on the lake just know that I always have and always will respect other peoples right not to hear my music...LOL But the lake I frequent has areas when everyone gets together and either ties up in the middle of the lake or pulls up on a sandy shoreline and parties a little.

Thanks everyone in advance for your help, its greatly appreciated!!

Jason

 

[sutor623]

Re: Help installing Amp and Subwoofer (battery wiring)

Dude I could help you with this, but this seems to be the wrong forum for this type of thing. Plus, without constant stator/alternator output, that amp will run your battery down fast. Do you plan on using this system when the boat motor is OFF?

 

[sutor623]

Re: Help installing Amp and Subwoofer (battery wiring)

Most stereo amplifiers for cars are 12V which means, one battery at a time, PERIOD! Some guys in their cars have a switch to swap back and forth between batteries. The bass on a boat will be much weaker since it cant dome off the back of the car. I have heard of trickle chargers, but there is no way it would keep up with the demands of the amplifier. As far as charging system on boats, I dont think they are really made to repower the battery to run a 1000watt amplifier. Basic rule says take wattage divided by volts = amps. So 1000w/12V equals about 80 or so. So 80 amp hours. Most marine batteries are 24 or 27 amp hours.Just running that one amp alone at highest draw would THEORETICALLY run for 30minutes. And that is with nothing else running to it. Plus you arent supposed to run these batteries past 50%, so now we are talking 15 minutes. And dont even think about trying to start up the motor with the same battery if you chill and go swimming for a bit with the stereo on. Those motors take some serious amp draw to start up. Honestly Id go with a face deck, 25w by 4 and get some decent marine speakers, and you will sound fine.

 

[sutor623]

Re: Help installing Amp and Subwoofer (battery wiring)

Sorry dude I did some editing, had to check my math.

 

[bird391]

Re: Help installing Amp and Subwoofer (battery wiring)

Dude I could help you with this, but this seems to be the wrong forum for this type of thing. Plus, without constant stator/alternator output, that amp will run your battery down fast. Do you plan on using this system when the boat motor is OFF?

I will be running it with both, I see guys out on the lake all the time running subs and large PA tower speakers.

 

[bird391]

Re: Help installing Amp and Subwoofer (battery wiring)

Most stereo amplifiers for cars are 12V which means, one battery at a time, PERIOD! Some guys in their cars have a switch to swap back and forth between batteries. The bass on a boat will be much weaker since it cant dome off the back of the car. I have heard of trickle chargers, but there is no way it would keep up with the demands of the amplifier. As far as charging system on boats, I dont think they are really made to repower the battery to run a 1000watt amplifier. Basic rule says take wattage divided by volts = amps. So 1000w/12V equals about 80 or so. So 80 amp hours. Most marine batteries are 24 or 27 amp hours.Just running that one amp alone at highest draw would THEORETICALLY run for 30minutes. And that is with nothing else running to it. Plus you arent supposed to run these batteries past 50%, so now we are talking 15 minutes. And dont even think about trying to start up the motor with the same battery if you chill and go swimming for a bit with the stereo on. Those motors take some serious amp draw to start up. Honestly Id go with a face deck, 25w by 4 and get some decent marine speakers, and you will sound fine.

I see guys out on the lake all the time running subs and large PA tower speakers. Keep in mind Its gonna be a bridged amp so it will only be running 500 wats at pek power, The amp itself is maybe 200 watts RMS.

 

[bird391]

Re: Help installing Amp and Subwoofer (battery wiring)

Dude I could help you with this, but this seems to be the wrong forum for this type of thing. Plus, without constant stator/alternator output, that amp will run your battery down fast. Do you plan on using this system when the boat motor is OFF?

This forum states Electrical, Electronics and Audio

 

[sschefer]

Re: Help installing Amp and Subwoofer (battery wiring)

Parallel up a couple of Odysee (sp) PC2500 as house batteries. Put in a Blue Sea add a battery system to isolate your starting battery from you house batteries. The ACR will charge the house batteries when the engine is running but will not allow the starting battery to be drained unless you put the switch in the "Both" positon. What you're trying to do isn't much different then what us fisherman do for our trolling motors. Two PC2500's will run you between 900.00 and 1400.00. Battery Mart had them the cheapest but they're 6 weeks out on delivery. Optima and Odysee are made by Johnson Controls. The PC2500's have and RCA rating of 240 minutes @ 25 amps. Two of them in parallel might give you about 3 hours of engine off music. These batteries will produce 12v all the way down to 20% charge and do that without damage. They are pricey but you get what you pay for. The downside is that the life expectancy with proper maintenance is no better than the cheapest Wall Mart battery (also made by Johnson). It's all about the RCA's and max safe discharge. Save up for your first set install them and start saving for the next set. They'll last about 3 years and are dry cell so at the end of the season just charge them up full, turn the switch to off and they be ready to go for the next season. They do not discharge like other batteries.

 

[sutor623]

Re: Help installing Amp and Subwoofer (battery wiring)

Two PC2500's will run you between 900.00 and 1400.00.

Yeah good luck with that bird. So pretty much, not worth running a sub on the water.

 

[Slide]

Re: Help installing Amp and Subwoofer (battery wiring)

1. Should I wire one battery to the other battery or should I just leave it separate from the rest of the system and WHY?

You should get a switchable battery setup with an automatic charging relay. I believe Seasense makes one that will automatically isolate each battery in the system when it draws a load (such as cranking, etc). Do a little research on that, it is brought up often in this forum but I can't remember the product off the top of my head.

2. If I should connect the batteries together what would be the proper wiring and WHY?

See above, any multiple battery system will include a wiring diagram. There are also many diagrams available on this forum and on Google.

3. If I should run it separately what is my best wiring options and WHY?

Both will have to ultimately be in the same system unless you don't want the motor to be charging your house battery for some odd reason.

4. What type of battery should I buy and WHY? I'm thinking deep cycle.

Generally speaking, a dual battery system includes a dedicated starter battery and a house battery that runs all electronics and accessories. The starter battery can be a standard marine battery with the cranking amperage rating your boat requires. Your house battery should be a good marine deep cycle. Optima Blue Tops are the most recommended; I use one.

5. Would a capacitor help and in what way does it help in a marine setup?

It might, if you have a seriously high-powered sub. Best way to know is to run it without a cap, and if the lights dim when your sub hits, you need a capacitor. Stop running the sub until you add one at that point. Most boats (esp older ones) have pretty weak electrical systems, so it's a good idea to include the possibility of using one in your planning.

6. If I do run the batteries hooked together will my motor change both batteries?

Yes.

7. How does the charging system on an outboard motor work?

The same as any other motor. Newer outboards have more powerful alternators, but if you have an older outboard it's likely a stator that will only power 20A or less. This is a major limiting factor on anything you want to do so do some research on your equipment.

8. Should I consider an onboard charging system?

Only if you determine your motor charging system is inadequate for what you want to do. If you run the numbers and it adds up to dead batteries, either scale down your plans or plan on plugging it in every night.

FYI, when you're figuring loads, only do RMS wattage. You will get crazy numbers if you use peak wattage. Your setup sounds very similar to what's going in my Hydrostream, and the numbers do work (but close).

 

[Silvertip]

Re: Help installing Amp and Subwoofer (battery wiring)

Most stereo amplifiers for cars are 12V which means, one battery at a time, PERIOD! Some guys in their cars have a switch to swap back and forth between batteries. The bass on a boat will be much weaker since it cant dome off the back of the car. I have heard of trickle chargers, but there is no way it would keep up with the demands of the amplifier. As far as charging system on boats, I dont think they are really made to repower the battery to run a 1000watt amplifier. Basic rule says take wattage divided by volts = amps. So 1000w/12V equals about 80 or so. So 80 amp hours. Most marine batteries are 24 or 27 amp hours.Just running that one amp alone at highest draw would THEORETICALLY run for 30minutes. And that is with nothing else running to it. Plus you arent supposed to run these batteries past 50%, so now we are talking 15 minutes. And dont even think about trying to start up the motor with the same battery if you chill and go swimming for a bit with the stereo on. Those motors take some serious amp draw to start up. Honestly Id go with a face deck, 25w by 4 and get some decent marine speakers, and you will sound fine.

Ummmm --- the scoop on batteries is that a 24, 27, 31, etc is the "group size" (physical size) and is NOT the AHr rating of the battery.

 

[Silvertip]

Re: Help installing Amp and Subwoofer (battery wiring)

1) You definitely need a dual battery switch or some other similar configuration of which there are many.
2) You need the largest deep cycle battery you have room for and can afford.
3) You DO NOT wire the starting and house batteries "permanently" in parallel unless you want to get left with a dead starting battery (see #1).
4) You definitely need an on board charger since the engine alternator output is very low. You would need to run wide open for hours to keep the house battery charged.
5) Lastly, you are in a 17 foot boat situated a maximum of 8 feet away from all speakers so the cost for you and annoyance factor for other folks is questionable.

 

[bird391]

Re: Help installing Amp and Subwoofer (battery wiring)

Thank you.

 

[bird391]

Re: Help installing Amp and Subwoofer (battery wiring)

Ummmm --- the scoop on batteries is that a 24, 27, 31, etc is the "group size" (physical size) and is NOT the AHr rating of the battery.

Thank you

 

[bird391]

Re: Help installing Amp and Subwoofer (battery wiring)

You should get a switchable battery setup with an automatic charging relay. I believe Seasense makes one that will automatically isolate each battery in the system when it draws a load (such as cranking, etc). Do a little research on that, it is brought up often in this forum but I can't remember the product off the top of my head.



See above, any multiple battery system will include a wiring diagram. There are also many diagrams available on this forum and on Google.

3. If I should run it separately what is my best wiring options and WHY?

Both will have to ultimately be in the same system unless you don't want the motor to be charging your house battery for some odd reason.



Generally speaking, a dual battery system includes a dedicated starter battery and a house battery that runs all electronics and accessories. The starter battery can be a standard marine battery with the cranking amperage rating your boat requires. Your house battery should be a good marine deep cycle. Optima Blue Tops are the most recommended; I use one.



It might, if you have a seriously high-powered sub. Best way to know is to run it without a cap, and if the lights dim when your sub hits, you need a capacitor. Stop running the sub until you add one at that point. Most boats (esp older ones) have pretty weak electrical systems, so it's a good idea to include the possibility of using one in your planning.



Yes.


The same as any other motor. Newer outboards have more powerful alternators, but if you have an older outboard it's likely a stator that will only power 20A or less. This is a major limiting factor on anything you want to do so do some research on your equipment.



Only if you determine your motor charging system is inadequate for what you want to do. If you run the numbers and it adds up to dead batteries, either scale down your plans or plan on plugging it in every night.

FYI, when you're figuring loads, only do RMS wattage. You will get crazy numbers if you use peak wattage. Your setup sounds very similar to what's going in my Hydrostream, and the numbers do work (but close).

Very Very informative, thank you very much!!! This is exactly the type of input I was looking for!