Battery timeline question

 

New member
Username: Hpb

Post Number: 1
Registered: Jul-06
Not really a car audio question but more of a boat audio question. Was going to put a system into my houseboat and just thought i would ask for some advice. Couple of questions i have are:

(1). I wanted to wire my battery at the back of my boat and run the wires up to the front. It is a length of 45 feet. Then I was going to put a block of front to run the amps and head unit off of. Any recommendations on minimum gauge wire or type of wiring to use?

(2) I was going to add a second battery just to power the amp and head unit and that is it. A lot of the time I have music playing while i am out on the lake and at anchor and the engines arent running. I am looking at a 600 watt amp to run to sub woofers and 2 50 X 2 amps to run 4 speakers. About how long will a deep cycle battery keep the music playing on that type of setup before i have to keep the engines or generator on to charge them up?

Sorry for asking such newb questions but i am slowly but surely learning. Thanks for any help anyone can give me.
 

Gold Member
Username: Fandim

Reno, Nevada United State...

Post Number: 1299
Registered: Jun-05
At 45 feet, you should use at least 0 gauge, probably a couple strands of it, even.. As for how long it should last..really depends on the reserve of the battery, and the volume you're playing the music at.
 

Gold Member
Username: Carguy

Post Number: 5586
Registered: Nov-04
For your situation, get deep cycle 2nd battery and an isolator. Run 4 - 2 gauge wires, 0 gauge will cost you plenty, and unless you're powering high current devices, it won't be necessary.
Don't go cheap on the battery, get a good quality one like yellowtop from Walmart.
For sub amp, make sure it's class D or T. They will consume much less power. No need to get 600w, 300w - 500w is plenty with engine off.
Any higher, and you'll just be wasting power.
 

Silver Member
Username: N2audio

Lawrence, Ks USA

Post Number: 918
Registered: Mar-04
1/0 at 45' can provide about 900w rms before voltage drop would become a factor. 2 ga = less than 600.
 

New member
Username: Hpb

Post Number: 2
Registered: Jul-06
Thank you guys very much for the advice. This was exactly the kind of information I was looking for.

I am going to see if i can successfully run a 0 guage wire up the boat channel and hook it to a block up front to power the amps and headunit. I ended up getting a 400 watt amp for 2-12" subs at 4 ohms. Won't be ming blowing bass but will be a hell of an improvement from the no bass i have right now.

I was looking to be able to power the speaker volume independently from each other since sometime people are on the roof of the boat and i don't want to have music to loud on the front when i have it louder up top. Someone recommended using l-pads for this. Does that sound like a good piece of advice?

A deep cycle was exactly what i was thinking about using since it would allow me to drain it down farther without too much worry of ruining the battery. If i had the subs running and 1 set of speakers running about how long would a good deep cycle last without the engines running do you guys think?

As for the isolator, i am kinda new at this so i will have to do some searching around the boards to figure out exactly what to do with that, hehe.

Thanks once again for your guys' advice.
 

Gold Member
Username: Carguy

Post Number: 5587
Registered: Nov-04
The life of a deep cycle will depend on your amp's class. If the 400w is class AB, then it'll drain the battery much faster. However, if you purchased class D or T amp, then you should get 40% - 50% more life.
Typically, on a fully charged battery, you might get 30min - 1 hour. If you lower the volume, then 2 - 3 hours.
Reason why you need an isolator is, if you just wire 2 batteries in parallel, then your amp and HU will draw current from both batteries. That means when it dies, your boat won't start. Isolator will keep your 2nd battery from killing your starter battery.
As for controlling speaker volume independently, what exactly are you asking? I thought you only had sub and front speakers? Do you have more at the back or top?
 

New member
Username: Hpb

Post Number: 3
Registered: Jul-06
Altogether there will be six speakers. 2 on top of the boat run by a 50 X 2, 2 on the lower deck run by another 50 X 2, and then the two subs. I was thinking about putting the l-pads in so that the speakers could be controlled independently of the HU and be able to keep the music at a comfortable level. Plus the subs on a remote so that they can be turned off altogether occasionally so i won't piss of people when i am in dock.
 

Gold Member
Username: Carguy

Post Number: 5590
Registered: Nov-04
Are you saying that you will have 2 amps plus the sub for a total of 3?
If that's the case, you will be draining the battery very quickly.
Why don't you just put a switch on the speakers and use one amp? You can wire them so that, they all power up or just the ones you need.
 

New member
Username: Hpb

Post Number: 4
Registered: Jul-06
That would be the setup i would like the most, Isaac. I just wasnt sure what kind of amplifier i would need to get in order to do that. How many channels would i need and what kind of wattage would be needed to be able to hook a amp up to a subwoofer and 4 speakers? If i could pull it all off with just one amp that would be perfect.
 

Gold Member
Username: Carguy

Post Number: 5591
Registered: Nov-04
Xtant used to make 3 channel amps, one channel for the sub and the other 2 for stereo. They still might have some on sale at eBay.
If you want maximum battery life with good sound, then you will need either one 3 channel amp or one class D/T amp for the sub and another stereo/2 channel amp for your 6 speakers.
For your sub, I think you mentioned you already bought 400w amp, so that will do. For your 2 channel amp, the power will depend on how many of the speakers will be "on" at the same time. For example, if they were 50w rms each, then 2 of them on at the same time will require 50w rmx x 2 amp. If however, let's say you will always have 4 speakers on at least, then the amp's power will have to be 100w rms x 2.
Check the power rating on your speakers. In your case, I'd get 75w rms - 100w rms x 2 channel amp. That should be enough music power for your 6 speakers.
I'm sure you know how to install switches on the speaker wires right?
 

New member
Username: Hpb

Post Number: 5
Registered: Jul-06
Isaac, thank you very much for the info. That is exactly what i need to know. Switches i will be able to do without burning the boat down. As for the amp that i bought, it is a class AB. Would it be recommended to just ebay off the amp and get a class D or T amp instead? Being the impulsive person i am, I just bought the amp without doing the proper research and until this post didnt even realize their are different classes so i thank everyone for opening my eyes on that.
 

Gold Member
Username: Carguy

Post Number: 5592
Registered: Nov-04
If it's class AB, then use it for your 6 speakers.
Get a class D or T amp for your sub. They use a lot less current to produce same amount of bass.
Keep this in mind, when connecting 4 or more speakers to an amp, make sure you don't exceed minimum ohm requirement. Most stereo amps will handle 2ohms per channel.
Speakers wired in parallel drops the ohms in half, and in series, it adds.
Therefore, 2 4ohm speakers will equal to 2ohms per channel. You wouldn't want to add your 3rd speaker in parallel to it. Instead connect it in series to the pair in parallel. That will ensure that you don't fall below 2ohms.
« Previous Thread Next Thread »



Main Forums

Today's Posts

Forum Help

Follow Us