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Not Enough Current for Amps!

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=60688
Printed Date: May 10, 2024 at 5:59 AM


Topic: Not Enough Current for Amps!

Posted By: h2opolo_1255
Subject: Not Enough Current for Amps!
Date Posted: August 04, 2005 at 3:39 PM

Hi there! I've got a 93 civic ex coupe that i'm going to be putting 2 amps in. the first amp is a profile baja 4 channel. it puts out 80rms 160 peak per channel and it has 2 30 amp fuses. the second is an audiobahn A8000T sub amp. It puts out 800rms @ 2ohms (what i plan on running) and also has 2 30 amp fuses in it. Now by my calculations, thats gonna be suckin up a lot more current than my little 70 amp honda alternator is gonna be putting out. from my research i've come up with 3 solutions to this problem:

1#) Get a high output alternator (expensive?)
2#) Install a second Battery (complicated and expensive?)
3#) Capacitor? (not very effective?)

so ya... these are the options i'm aware of. Is there anything i haven't thought of that would work? Which option would be the most effective? which would be the most economical? WHAT SHOULD I DO?



Replies:

Posted By: DYohn
Date Posted: August 04, 2005 at 4:51 PM
Fuses in amplifiers generally indicate what the manufacturer determined would protect it from failure, not what they will draw during operation.  This means it will draw less than the fuse ratings by (on average) at least 20%.  This indicates the MAX current draw for those two amps shuld peak out around 100 amps with steady state current draw  between 40% and 70% of max, or between 40 and 70 amps if you run them as loud as they will play without clipping all the time.  I predict that your little Honda alternator might handle this load just fine.  But if not, high-output alternators for Hondas are relatively common and readily available.

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Posted By: h2opolo_1255
Date Posted: August 04, 2005 at 6:08 PM
Thanks for your input.  Thats good to know and hopefully i'm not going to need to step up my alternator.  when i get everything wired up, is there any signs (besides the obvious dead battery) that i should look for to make sure i'm not damaging anything?  and also, in the application, would a capacitor help?  i'm probably going to need one to help with my headlight dimming anyway, but would a cap help with making sure i'm not killing my battery?




Posted By: stevdart
Date Posted: August 04, 2005 at 7:33 PM
Don't put the cart before the horse.  Get your system set up and then determine if there is a power issue.

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.




Posted By: h2opolo_1255
Date Posted: August 04, 2005 at 7:55 PM
That makes sense...  is there any other ways besides finding myself with a dead battery i will know if there is a power issue?




Posted By: stevdart
Date Posted: August 04, 2005 at 8:02 PM
Oh yeah, it will be the 'headlight dimming' issue.  It shouldn't be a dead battery that alerts you to the problem.  The battery will just give 12.6 volts and whatever amperage it has stored.  It's the alternator that has to make the power, and when the car is running the power comes directly from the alt.  But I doubt, too, that you'll be seeing a need for a high output alt with what you say you are installing.  There is always the wiring upgrade under the hood that can be done first before the HO alt upgrade.

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.




Posted By: geepherder
Date Posted: August 04, 2005 at 9:17 PM

When you get it all hooked up, put your meter across the battery posts, and read voltage with the engine running, all accessories off.  Now turn all your accessories on- high beams, a/c on high, rear defrost, etc., and crank the stereo.  You should still see around the same voltage (usually 13.5v or better).  If you notice a substantial drop the second time around, look at an alternator, and keep the volume down until you can do so.

Hah, I didn't even read what equipment you were planning on putting in before posting this- you'll be fine.



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My ex once told me I have a perfect face for radio.





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