Extra battery?

hey guys right now i have a jbl 600.1 runnin at 1ohm so my system is around 600 watts right now. Soon im planning on gettin 2 more 12's and pushing by tham by the jbl1200.1 at 1ohm. So over all i would have 1800 watts rms. Now how will i know if i need a new battery or even an extra one as well as a new HO alternator. Please inform me on this, thanks.

No extra battery unless you plan on running the system in SPL contests or with the engine off. A battery does not create power, it stores it. The alternator is the way to go.

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Top Secret, I can tell you but then my wife will kill me.

Alrite that sounds good. I have a 1998 dodge dakota and im ont to sure what size alternator i have stock. and how do i know what size i need ? thanks.

It may be in the vehicle manual (doubt it) but more than likely a quick phonecall to the dealer or a Haynes manual should show you what alternator is in the vehicle.

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Top Secret, I can tell you but then my wife will kill me.

alrite thanks.and how do i decide how big of an alternator i need?

buy a capacitor.... you dont need any new batterys, and you dont need a bigger alternator.

Adam you are asking for trouble recomending a capacitor. That has been a hot topic here and most of the "Experts" here agree that a cap will not help. If anything it will make things worse. Do a search for capasitors and see for yourself.

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SonyES CDX-C90 - SonyES XDP-210EQ - 2X SonyES CDX-91 - SonyES XM-2100G

Adam, respectfully, do some research on the topic before making uneducated comments on it. This site is a great place to learn from and even after 18 years in this industry I still learn things every day, even from the forums like this one. Adam, here is what I mean. A cap is a device that needs to be charged. A battery is a device that needs to be charged. An amp is a device that need to get current. A battery is a device that gives current. A cap is a device that gives current.  A dead battery can give no current. A discharged cap can give no current. A alternator creates current to charge the battery and the cap. A alternator runs the electrical system in a vehicle when the engine is on. Excess power generated is stored in the battery. Basically a cap does not create power, it stores and uses it. If the demand of the system being installed is greater than the vehicles ability to create power, a bigger alternator or power creation device is necessary. Stick around and learn some things and then pass on the proper information to others. It is always better to be right than wrong.

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Top Secret, I can tell you but then my wife will kill me.

ya so anyways im already aware about how caps are a waste of money, so how do i know how big of an alternator i should get? ill be running 1800 watts rms.

With 1800wrms..I would reccomend a good 200 amp alternator. Upgrading your battery is also a good idea, but isn't a must with a sufficient alternator. Just something to think about.

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Dave

Pioneer Premier DEH-P660
15" Kicker CVR
Profile AP1000M
It's Loud

Yeah get a cap, strain your alternator more, good idea.  Anyway to get a rough calculation of how many amps you are going to need you need to divide your power into volts.  You want to take your rms wattage and double it, so (1800 x2 3600), so 3600 /14.4 ( I am only guessing 14.4, I don't know the actual voltage of your car), so you will be pulling roughly about 250 amps, but there are so many variables in this equation, just get somewhere in the area of 200 amp alternator if you can and you should be good.

alrite thanks alot, and with 1800 watts rms do you think i should get an extra yellow top battery? and your kidding about about the cap right.

I don't think he is kidding, but do not buy one. They ARE NOT an additional load on your alternator, but they do little to NOTHING for a system. If you have a yellow top battery already, yeah, another couldn't hurt, but if you are not using a yellow top already, GET AN IDENTICAL BATTERY TO WHAT YOU ARE PRESENTLY RUNNING. Run it in parallel with the first battery, and leave out any and all isolating devices. They do as much for a system as a cap does - NOTHING.

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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."

alrite thanks you guys. and right now im using 4 guage to wire everything. when i get another 1200watts rms running what gauge should i wire it at

Well I was not kidding, I was being sarcastic.  Caps will not generate more current, only store it, sorry for the confusion.  You will probably need to run 1/0 ga to be on the safe side.