Is my math right? Do i have the concept down?

[FluffyChicken]

Example: If I buy 3 125a/h deep cycles. That would equal 375 total amp hours when they are ran in parallel correct? So if i have a sound system that draws a total of 40 amps then i simply divide 375 by 40 which is 9.375. That means i can play my stereo for about 9 hours before the batteries will need a recharge?

 

[bruceb58]

Re: Is my math right? Do i have the concept down?

You typically don't want to draw them down over 1/2 their capacity...at least not often. Your math is correct.

How did you come up with the 40 amps?

 

[Silvertip]

Re: Is my math right? Do i have the concept down?

Probably has a gazillion watt amp.

 

[drewpster]

Re: Is my math right? Do i have the concept down?

Please correct me if I am wrong. Amp hour capacity is based on the amount of time the battery is used and the amount of available current per hour through that time. Amp/ hour rating is based on a 10 or 20 hour period.
In other words a 125 amp/hr battery can deliver 12.5 amps per hour for ten hours until a minimum voltage is reached. That minimum is 10.2 volts I think, or dead. So a 375 amp/hour bank can deliver 37.5 amps for 10 hours.
Obviously this is based on a perfect world scenario, There are all kinds of derating factors. Also discharging the batteries below 50% of capacity and failing to recharge them completely in a short time can limit their life span. So limiting jam time may be a good thing, as well as making those of us who like quiet time on the lake like you better. teehee!

 

[FluffyChicken]

Re: Is my math right? Do i have the concept down?

A quick way to see how much current your amps draw is to divide the the total amps of the fuses on the amp by 2. Its not 100% accurate. Its actually more then what it truley draws but its a quick way to get an idea. I was planning about 2000 watts but i've been thinking of the weight and how much a pain in the ***** its going to be to buy batteries and charge them so i may tone it down a bit. I was going w/ 4 12 inch subwoofers and 8 6.5's. I think im going to stick with just 2 12 inchers and 4 6.5's.

 

[Silvertip]

Re: Is my math right? Do i have the concept down?

What body of water will this boat be on? Some of us will not want to go there when you light up this system. The receiver in my boat boasts 7W per channel and is just fine -- and it doesn't annoy anyone.

 

[FluffyChicken]

Re: Is my math right? Do i have the concept down?

I have had loud stereos since i could drive a car. The boat deserves the same. I will be lake erie near edgewater. Chances are that im out when your sleeping anyways so we should be cool.

 

[Texasmark]

Re: Is my math right? Do i have the concept down?

Yeah, we each have our niches which hopefully both sides respect......the jamsters and the tranquility seekers.............aaaaaaaah peace and quiet. How blissful.

Guess which side I'm on. Grin

Mark

 

[Rancherlee]

Re: Is my math right? Do i have the concept down?

I'm all into loud stereo in cars (use to compete quite a bit) but In my boat I respect others. I have a kenwood cd/mp3 deck powering a pair of mtx 6.5: marine speakers and its more than enough on the lake, sound carries a long LONG way on water and its easy to annoy people with a loud stereo. Last time I was out camping I could still hear our campsite radio over a mile out on the lake and it was at a nice moderate listening level.

 

[FluffyChicken]

Re: Is my math right? Do i have the concept down?

So im guessing something like 8 6.5's and 2 12's will carry pretty far. When i launch late at night and im out around 3-4am the cleveland water crib has a horn that beeps like every 2-3 seconds. I can hear that thing over 3 miles away at night so your right. Sound really does carry out there.

 

[Zeusdafreak1]

Re: Is my math right? Do i have the concept down?

I just installed 2 sets of components and a 4-channel AB amp in my boat. One of the comp sets is a 7" set with 7" midbasses. The other is a 6.5 comp set. I didn't have anyway practical to mount subs so I went with the comp sets with the larger midbass. I found out I didn't need the subs anyway!

On the sandbar last Sunday everyone turned their radios off and listened to mine because the volume and clarity was good enough to carry 6-8 boats in either direction.I have a 30GB Ipod interface in my boat with approx 14 days worth of "good" music.

If you don't like 80's music or classic rock.......................FIND ANOTHER SANDBAR! LOL!!

 

[Texasmark]

Re: Is my math right? Do i have the concept down?

My comment didn't have to do with beach parties.

My comment had to do with easing into a secluded cove, meticulously placing the "perfect" lure in the perfect spot with all the adrenalin running waiting for that trophy fish and here comes dexter dip-xxxx between you and the bank with his radio blaring.......and when he leaves the cove, passing you again, it's at WOT.

Big Differerence.

Mark

 

[FluffyChicken]

Re: Is my math right? Do i have the concept down?

I wish there were some cool sandbars by me. I'm sure their are but i have no clue where. I'm in cleveland ohio.

 

[Zeusdafreak1]

Re: Is my math right? Do i have the concept down?

I have a fishing boat as well. When I fish I don't care for those types of interuptions either. We all like to kneeboard and I try to stay as far away from fishermen as possible. When we are kneeboarding there is nothing better than enjoying the water jamming to "into the ocean" by Blue October and ripping back and forth but not around anyone fishing.

We stop half-way through the day to party at the sandbar, cook shish-ka-bobs on the grill, and let the kids play in the sand and throw the frisbee. We may go back out and tube of whatever. While we are on the sandbar all 10-12 boats(5-6 in each direction) listen to MY stereo spinning tunes from my 30gig Ipod..................But we respect the situation. No blarring radios in the fishing holes. Its a matter of respect.

 

[FluffyChicken]

Re: Is my math right? Do i have the concept down?

Well lake erie is pretty huge and i'm a fisherman myself. I do respect those fishing.

 

[Big Keepers]

Re: Is my math right? Do i have the concept down?

Unless you have a 45' yacht, how loud does the system need to be when you're standing two feet away from the speakers?

FYI straight out of my class notes:

Amp-hour capacity - amount of amps that a battery can discharge at a constant current for 20 hours and have a final voltage of 1.75 volts per cell.

MCA (marine cranking amps) - The discharge load, in amperes, that a new fully charged battery at 32?F can continuously deliver for 30 seconds and maintain a terminal voltage equal to or higher than 1.2 volts per cell.