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Sup guys! Got a question...i just got my JL 1000/1 amp and JL 12W7, I was wondering if my stock alternator can handle it. Reason why i ask, is cause i put the same setup in my 99 civic si and it fried my alternator. if Anyone has any feedback, it would be greatly appreciated.
 

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i would def get a biger alternator. also yellow or red optima batt...
 

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ACTUALLY a devoted yellow top optima w/ a master fuse and some cap's in line with the battery and amp "should" take care of that. just use an isolator off the alternator to split the in-comming curent. that way the stock power set up is not comprimised. IE: no posible warenty issues..
 

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There is a lot of confusion about this topic but Ohm's Law can help us here. The amount of current demand your system will have on your charging system depends upon the amp and your listening habits.
First lets look at what your vehicle needs to run. Depending on which and how many accessories you are using, you vehicle will need 40 - 60 amps to operate.
Your amp is rated for 1000 Watts RMS @ 12.5V. Current (amps) = Power (Watts) / Voltage. So lets's plug this into the formula: 1000 Watts/12.5 Volts = 80 Amps.
This is not the whole story hower. The number above assumes the amp is 100% efficient, but it's not. A design like this amp has great efficiency but when you consider the greater levels of clipping the amp will be exposed to it's efficency is about 50%. This means it will need 2000 Watts to generate 1000 (yikes). So lets see: 2000 Watts/12.5V= 160 amps plus the 40-60 amps you car needs, you need a 200 - 320 amp alternator just to feed this one amp....or do you?
You are the other factor. Your listening tastes dictate how much of that availabe power you are going to use with music. Most people will use 20% of the amplifier's power on average with music:
1000*.2=200 Watts (average)
(200*2)/12.5=32amps (average)
If you are like most people, you probably will not need to change the alternator if it's healthy.
Abusive poeple will use 50% of the amplifer's power on average with music:
1000*.5=500 Watts (average)
(500*2)/12.5=80amps (average)
Probably should upgrade. If you burned up your last alternator, you fall under the "abusive" category!
The major difference between these two types of listeners is the amount of clipping they will drive their systems to. Most people will drive their systems into clipping, some more than others. Clipping dramatically increases average power.
There are other factors that influence average power like Crest Factor of recordings but that is a different discussion.
Here is an example of clipping and average power:

Normal Signal Without Clipping

Moderate Clipping (very common)

Heavy Clipping (Abusive)
Note as the level of clipping increased, so did the average power.
 

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Originally posted by Mandrek@Oct 25 2004, 07:09 PM
ACTUALLY a devoted yellow top optima w/ a master fuse and some cap's in line with the battery and amp "should" take care of that. just use an isolator off the alternator to split the in-comming curent. that way the stock power set up is not comprimised. IE: no posible warenty issues..
All energy to move a speaker ultimately comes from the alternator. Adding an extra battery and (especially) an isolator will actually reduce the available current to the system. Adding extra batteries will increase the reserve time which is handy if you plan to listen to the system with the car off, but the charging system will still hit a wall eventually. Capacitors can never charge to a higher voltage than is available so it doesn't do much to help a charging system in trouble. There is no such thing as a free lunch!
 

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hmmm odd my calculation must be off then. that and my constents that i had assumed where wrong too. i had assumed that he was a "normal" user, whom had most likely hit too high a current demand once. thus the preposed use of the caps..... hmmmm.... back to the board for this one.
 
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