Hi I need some help. Have a baddie that has a mean sound system in his car and he has become a real idiot about it so I have come to a point where I can take no more. I got in my cat and drove to a sound shop and got the strongest stuff they had. Have sorted out how to connect it all and have the box but I don't know how match battery power I need. I have tow SSAD-EC1-8000 AMP'S 3000watts RMS. And I have them strapped. (Master and Slave) Then the tow SSWD-8150 Subwoofer 2000watts connected on a 1.5ohm connection So how do I work out the battery power needed?
Calvin's on the right track -- if you're really looking to power 6kW the starting point is a HUGE (or a 2nd) alternator. A high quality 2nd battery would probably help, but the alternator is where you need to start.
Guise you have to take a step back and think about it. To power the tow amps I will need as you say about 6KW but my car has a 120amp alternator on already which at best can give me 1.62 KW so if you want me to power this hole setup from an alternator I will need @ 12V 500amp. I don't think thy make them that big.
No YOU have to take a step back. You're not going to need full power out of your amps all the time - it would be closer to the truth to say you'll never need full power. 6000w at 75% efficiency would require about 8000w from your charging system which is 570A (at 14v). However, music requires no where near constant full power from your amps. Playing music at full volume you'll be using no more than 1/3 the power your amps are capable of, so take that 570A down to around 190A. Now assuming you do enjoy the use of your ears and you won't be blasting it all the time you can knock another good 50-100A off that.
So let's say you're looking at 50-100A rms current draw plus the 20-40A the car's standard electrical system will need and you can begin to see why a high output (200-250A) is the key to making a system like this a possibility.
Your alt doesn't do ALL the work, but it does have to keep the battery charged.
Even at 250A you'd still be maxing the alt out for short bursts of high demand music power, which is where the battery or batteries would pick up the slack, but at any time other than that the batteries would be getting charged.
N2audio I want to compare it agents Frank at a sound competition as this is the only definitive way to see how wins. So at this competition you have 3 classes that I want to play. First is SPL witch I will only need the power for five seconds or so. Then in the second on bass boxing 1 minute and then the thirds bass boxing for 2 minutes. So I have to bulb a system that can handle full power for 2 minutes at least. So at this point in time I am thinking of running 2x 2000 amp cold crank (I.E.C) batteries and the another 3 1.5 volt cells to bring the voltage up. Then I shoed have about 16volt at 4000amps = 64kw at max. Then draining all that power the voltage will drop if you take in to consideration that I.E.C specification which states that the battery voltage will drop 1.4volt per cell after 60 seconds giving me 8.4volts. That is to low and the reason for the extra 3 1.5 volt cells.
If I had known you were setting up for a comp specific application I probably wouldn't have bothered replying. Your theory sounds logical, but I would think you're going to have some trial and error before you get things just the way you want them.
Sounds like quite a project to me. Good luck with all that.