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Calculate current draw ?

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=64275
Printed Date: May 14, 2024 at 8:35 AM


Topic: Calculate current draw ?

Posted By: arrow12
Subject: Calculate current draw ?
Date Posted: October 12, 2005 at 10:32 PM

Can somone please help me calculate the current draw from the alternator for this system?  There is a Kenwood Excelon KDC-X589 headunit (22Wx4, 50Wx4 max output), 2 Alpine MRP-T220 amplifiers (70Wx2 at 2 ohms, 90Wx2 max output, 14.4 input voltage), and 1 Audiobahn A8000T amplifier (800Wx1 at 2 ohms, max output N/A, 12.5 input voltage.  I can't figure out how much current I am drawing from the alternator and battery.  I am having trouble understanding the calcualtion formulas on this site too.  Any and all help is appreciated.  Thanks.



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That's my opinion. Take it, leave it, or correct me.



Replies:

Posted By: dwarren
Date Posted: October 12, 2005 at 11:26 PM

I am not sure on this one, but that calculator gives me a total of about 75 amps (rounded the wattage to 1000 @13.5volts) . So if that's correct the smallest alternator to use would be a 150 amp, assuming your stock one is between 60-70. I would go bigger if at all possible as upgrades may arise in the future and just to be on the safe side. But again I am not sure my calculations are right.



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Posted By: dh205
Date Posted: October 12, 2005 at 11:41 PM
dwarren, i have a similar situation. in addition to the stuff i have on my signature, i have 2 tsunami 2 farad capacitors. they display voltage at all times and almost always show between 14.0 volts and 14.2 volts. i calculate the amp draw to be around 70 amps. do you have any idea how many amps are produced by the 2004 honda accord lx 4 cyl. sedan? i have searched all over the place.

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2004 hondaaccord sedan alpinecda9827HU, 2kicker sx650.1monoamps, alpinemrv-f540 4ch, 2 kappaperfect 10.1svc subs(350rms ea.), kappa 6.1 components(front), kappa 693.5i 6x9's(rear).
                 




Posted By: dwarren
Date Posted: October 12, 2005 at 11:48 PM

I would guess some where between 50-80 amps. You should contact Honda if you need the exact number, but either way you are probably exceeding the stock alternator's capacity.

What are the specs on those amps  you have? 



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Posted By: dh205
Date Posted: October 12, 2005 at 11:50 PM
the 2 sub amps (kkr sx650's) are running 325W each @ 4ohms. the alpine 4 channel is runnig 80W/channel @ 4 ohms.

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2004 hondaaccord sedan alpinecda9827HU, 2kicker sx650.1monoamps, alpinemrv-f540 4ch, 2 kappaperfect 10.1svc subs(350rms ea.), kappa 6.1 components(front), kappa 693.5i 6x9's(rear).
                 




Posted By: dwarren
Date Posted: October 12, 2005 at 11:57 PM

I've been using this calculator>https://www.the12volt.com/ohm/page2.asp#13 The very first one.



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Posted By: dh205
Date Posted: October 13, 2005 at 12:01 AM
.....14.1 volts, 650watts from subamps, 80X4 from 4channel= 970watts. i get 69.2 amps...you think i am playing with fire by not getting a HO alt?

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2004 hondaaccord sedan alpinecda9827HU, 2kicker sx650.1monoamps, alpinemrv-f540 4ch, 2 kappaperfect 10.1svc subs(350rms ea.), kappa 6.1 components(front), kappa 693.5i 6x9's(rear).
                 




Posted By: dwarren
Date Posted: October 13, 2005 at 12:09 AM

Here's the deal, that alternator is designed for that particular car and it's electrical needs, nothing more. So yes you are asking it to do more than it can produce. The degree of how much stress that is put on the alt. may vary too. When you use lights and other accessories it is stressed that much more. 

Do your lights dim while you play your stereo? By the way those caps are actually more detremental to your car's electrical system right now. The reason being is when they are drained by your amps, the electrical system must fill them up again, and again. This adds extra stress to it all. When you do upgrade the alt. you may include the caps. 



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Posted By: dh205
Date Posted: October 13, 2005 at 12:13 AM
my lights do not dim when it hits. but i was told by "a guy who really knows his stuff" that i didn't need a ho alt. but, what you're saying makes sense and i have read countless threads about this stuff. i just figured that because my lights weren't dimming i was good to go. i will have to look into the HO alt market. worth getting a yellowtop as well?

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2004 hondaaccord sedan alpinecda9827HU, 2kicker sx650.1monoamps, alpinemrv-f540 4ch, 2 kappaperfect 10.1svc subs(350rms ea.), kappa 6.1 components(front), kappa 693.5i 6x9's(rear).
                 




Posted By: dwarren
Date Posted: October 13, 2005 at 12:17 AM

I don't use any special batteries, but then again I don't listen to my music while the car is off.

Your lights don't have to dim in order for there to be stress on you car's electrical system. Your battery may taking the brunt of the abuse, for now. The scary thing about that situation is you can damage the on board computer and your gear! 



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Posted By: dh205
Date Posted: October 13, 2005 at 12:27 AM
thanks, bro. i'm gonna definately look for a new alt.

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2004 hondaaccord sedan alpinecda9827HU, 2kicker sx650.1monoamps, alpinemrv-f540 4ch, 2 kappaperfect 10.1svc subs(350rms ea.), kappa 6.1 components(front), kappa 693.5i 6x9's(rear).
                 





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