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170 amp alternator

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=60790
Printed Date: May 12, 2024 at 7:14 AM


Topic: 170 amp alternator

Posted By: adix5689
Subject: 170 amp alternator
Date Posted: August 05, 2005 at 9:45 PM

I have a 170a alternator. How Do I calcutate how many amps I can draw off the alternator. I want to run a 2200watt system. Will 170a alternator and a kinetic battery be enought.



Replies:

Posted By: sedate
Date Posted: August 05, 2005 at 10:46 PM
Hmm.

Amps = Watts/Volts
183 = 2200/12

Now this is sort of a tough question. This depends an awful lot on a number of things... far to many to really give you an adequete answer.

My inclination is to tell you that with a deep cycle battery and an alternator that big, you ought not have big problems.. even with a draw like 180 amps... (keeping in mind that you might as well increase that to 225 - 250 accounting for amplifier inefficencies) .. you certainly aren't going to be pulling that all the time....

Of course, your alternator is not going to be producing 170A all the time... generally alternators reach full output somewhere slightly above a crusing rpm..

So eh.. your in the right neighborhood but this really is kinda one of those things you have to hook up and find out.


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"I'm finished!" - Daniel Plainview




Posted By: NicP
Date Posted: August 06, 2005 at 2:19 AM
alternators dont run at 12 volts, they generally run a little above 14 volts




Posted By: sedate
Date Posted: August 06, 2005 at 9:24 AM
Hmm.

Amplifiers are *not* going to be seeing a constant 14.4v, particularly under the load of 2200watt stereo.

Just because the alternator's native voltage hovers a hair above 14v doesn't mean that is what his stereo will see, or, for that matter, what his vehicles voltage will be.

Like I said, lotsa stuff plays into this. Ultimately, math really isn't the point. He'll still have to hook it up and find out.

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"I'm finished!" - Daniel Plainview




Posted By: stevdart
Date Posted: August 06, 2005 at 9:43 AM

adix5689 wrote:

I have a 170a alternator. How Do I calcutate how many amps I can draw off the alternator.

There's no calculation here.  It's a 170 amp alternator.



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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: Master Asylum
Date Posted: August 06, 2005 at 10:30 AM

First thing is, is that 220wRMS or just peak power? If it is peak you'll be fine. I'm running like 2600 watts peak on a 105a alternator and a yellow top. And from what I've heard the cells do great for trunk battery for system. Just my 2 cents.



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1998 Monte Carlo w/
Eclipse CD8454
2xRockford 5.25" Power 2-way T152C
2xRockford 6"x9" Punch 3-way FRC4369
1xMemphis 16-MCH1300 5-channel
2xKicker 12" L5 Solobaric-2 Ohm




Posted By: adix5689
Date Posted: August 06, 2005 at 5:03 PM
I want to run 2200rms on a 170amp alternator.




Posted By: haemphyst
Date Posted: August 06, 2005 at 6:22 PM
OK, Pay attention, this is testable material posted_image:

2200 watts (OUT) times 1.33 = 2926 watts (IN) divided by 12 volts (nominal, NicP) equals 243.3 amps.

Does 243.3 amps "fit" into a 170 amp alternator? No. are you going to be running 2200 watts ALL THE TIME? NO, and I GUARANTEE that... I have close to 6kW in my trunk, and I am using a 165A alternator... not a single problem. BUT, to answer your question in an absolute fashion, no, it will not be big enough. sedate told you there are mitigating circumstances to this answer, and I have told you that I am running FAR more than one woud think would be possible on my alternator...

(Also keep in mind this 170A is probably a clod rating - you need to derate by a MINIMUM of 10 to 15% for hot output...)

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."




Posted By: NicP
Date Posted: August 06, 2005 at 11:05 PM
Youre more correct than you think about being testable material ;)

Why would you use 12 volts? most amplifiers are rated at 14.4v, if you use 12 volts it is most likely that the amplifier will not be putting out 2200w

But as everyone else said there are too many factors to give you a calculated answer, we dont know how much of the power the car and accessories will be using, we dont know the inefficiency of the amplifier (thus how much current it will really draw) and we dont know what the realistic output of your alternator will be

Having said all that itll probably be fine you dont plan to drive around with 2200w of power and have it on full volume all the time now do you?





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