Adding 4 amplifiers-Battery consumption questions

[kbond]

Hey folks,



I adding the MTX 2 10" sub box and 4 amplifiers to equal close to 800 watts @ 4ohms. My question is should I add one of those battery capacitors to help with the load or should the dual battery setup our trucks already have be enough?



Thanks for any help.



Ken

 

[Mark_Kendrick]

What amp are you using? Chances are the RMS wattage is much less than that. Take a look at distortion rate at that wattage.



The ampplifier can never pull more amperage than the fuse on the side of the amplifier.



I'll try to make it short. .



Take the RMS wattage rating and asssume 80% efficiency(it should be better than this)



w=v*a so . . w(1. 2)/12=amperage

so 400w RMS == 480/12= 40 amps. . You will not pull this amperage all the time. . under normal listening conditions you will use 1/4-1/3 of that.



the truth is that most vehicles operate at 14. 4v so electronics use less amperage.



If you listen to 400w of bass for any prolonged periods you will get hearing loss and a headache... but cranking up your favorite song or jaming out for a half hour or so never hurt me much usually the phone rings or SHE complains or you get home.



You have a 130 amp alternator . . I think. . handling instantaneous 40 amp draws will not be an issue and sustained draws of 20 amps should be no problem for our electrical systems. If you see lights dim on heavy bass notes. . check your grounds, be sure you have a large enough power cable to the amp and you may want a large capacitor.



Its likely that you will need at least an 8ga supply line. . if you really do pull 40 amps use a 4ga. use 10 or 12ga speaker wire. Solder any connectios you can and use as few quick connects(on the back of speake boxes) as possible. The name of the game in 12v audio is efficiency. thicker wire and soldered connections lose less voltage(it gets changed to heat).



Sorry so long . . hope it helps.



Mark

 

[kbond]

amps and battery draw

Thanks for the good info Mark.



I am using 3 Rockford Fosgate punch 250. 2's and 1 800. 2.



The 250. 2's are claiming:



62. 5 W X 2 @ 4 Ohms RMS @ 1% THD



125 W X 2 @ 2 Ohms RMS @ 1% THD



250 W X 1 @ 4 Ohms Bridged RMS



and the 800. 2 is claiming:



200 W X 2 @ 4 Ohms RMS @ 1% THD



400 W X 2 @ 2 Ohms RMS @ 1% THD



800 W X 1 @ 4 Ohms Bridged RMS



I was planning to run 1 4g lead from the battery and split it 4 ways via 8g to the amps.



My days of booming out the nieghborhood are long gone but I got such a good deal on everything I figured what the hay.



Thanks again for your help.



-Ken

 

[Mark_Kendrick]

no problem,

I worked for a couple of stereo shops in college. the prices have gone up but the physics are still the same



gimme a yell if you have any questions. Most shops you go to act like its rocket science.

 

[b.j.oneill]

I have a 2000W Lanzar Opti Drive and a Auto Tek 250w SS the Lanzar pushes 3 LJ WS6s subs and the SS pushes my componets never had a problem with the stock power setup.

 

[jwgary]

are you running the stock batteries? If so, you need to get rid of those anyway. Get some yellow top Optimas and most of your power issues will disapear. The double battery setup gives us a great advantage for stereo installs already. I do question your need for that much power though. Can you not run the subs 2 ohm mono? You wouldn't need as much power that way. My brother had three JL 10W6's in his dakota and hit 154. 7 dB with 600W t 2 ohm. He then was able to get 171dB with 1600W at 1ohm long enough to go through the competition line (don't run like that if you want your components to last a while) How are you splitting the power with your mids and highs? Good luck in your install.

 

[Cooker]

IMO,



Given your setup, I don't think you will need a cap. unless you plan on playing very bassy music really loud for long periods of time. It doesn't sound like you will be doing this. Dual batteries and a 135 amp alternator really help out.



Do you have DVC 10's? I agree with jwgary, the best way to get the most bang for your buck out of a sub amp is to run it at 2 ohms. That way you'd be running 400watts/sub vs 200 watts. .



If you are going to run your sub amp at 2 ohms, I would recommend (2) 4ga power supply lines to the amps. One to the 800. 2 and the other split to the 250. 2's



-Ryan

 

[J.R. Adkins]

When I added my cap it really made the music more accurate. The highs were more crisp and the bass hit like a cannon!

 

[Mark_Kendrick]

007-laf:-laf)



be careful. . if you push that set of amps as hard as you could you'll be deaf and broke. but you won't have to listen to the better half :-{} anymore:-laf



seriously, depending on how hard you push those amps you could get away w/4ga or NEED 0ga! 1/2farad (or more) never hurt anything but it gets pricy when you turn audiophile on wheels.



This truck is the first vehicle in 10 yrs that didn't thump pretty good. . lately I listen to the cummins sing that holset tune



good luck,

Mark

 

[kbond]

Thanks to all

Thanks to all for your imputs.



I'll let you know how it turns out.



-Ken