alternator power distribution
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=104210
Printed Date: May 14, 2024 at 11:45 AM
Topic: alternator power distribution
Posted By: mylar
Subject: alternator power distribution
Date Posted: April 23, 2008 at 5:31 PM
I've recently started having problems with my batteries. I have 2 Kx1200.1 kicker amplifires powering 2 12" Kicker solobaric L7s... theres and 12 farrad cap powering both amplifires... I had 2 optima yellow tops in my car but I wore one of them out... and now I bought an optima red top to start my car and was thinkin about gettin a Blue top to power my stereo... The guy at the stereo shop said all I need is a battery isolator relay.... this allows my primary starting battery to be isolated when the car is off, to insure its starting capability... but I know different batteries have different ammounts of resistence and the alternator is more likely to charge the one with the most restistence... What do I need to make sure both batteries are charging equally off the alternator??
Replies:
Posted By: Alpine Guy
Date Posted: April 23, 2008 at 7:01 PM
Your going to continue having troubles with your batteries if not your amps. You are drawing WAYYYYYYY too much power for a stock alternator to handle, if you continue this, your going to fry your amps, as well as more battery's. Batteries and capacitors don't make power, they just store it, the alternator makes the power that the batteries store.
Now to the battery issue, if you wire them directly together, they must be identical batteries, made from the same batch, otherwise one will drain the other. If you use an isolator, it basically just shuts off one battery when your ignition is off, when your ignition is on both batteries are connected to the alternator, whatever one is drained the most, or has the lowest voltage will pull down the other battery too which will cause the alternator to see that there is a power demand and output more power to "try" to keep up to your demand.
Basically, if you play your stereo for more than 15 minutes at a time when the vehicle is off, then an extra battery will help you, but other wise it is only another load on your already overloaded alternator. If you only play your stereo when the engine is running than you just need an high output alternator.
Either way, both cases, you need an alternator that will put out at least 100 amps more than your stock unit.
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2003 Chevy Avalanche,Eclipse CD7000,Morel Elate 5,Adire Extremis,Alpine PDX-4.150, 15" TC-3000, 2 Alpine PDX-1.1000, 470Amp HO Alt.
Posted By: mylar
Date Posted: April 23, 2008 at 10:48 PM
Well, I already have the biggest alternator that will fit in my car... I cant remember but its either 105 or 110 amps... so what would you suggest for charging an optima red top starting battery and a blue top for the amps... the blue tops are extremely deep cycle... I want the batteries isolated so the amps can only draw on the blue top.. but both batteries get maintained by the same alternator... I understand what the isolator does... I just dont know what needs to be done so 2 different types of batteries can be charged off the same source...
Posted By: jmelton86
Date Posted: April 23, 2008 at 11:01 PM
If you want both all batteries to be charged off of the same source (alternator), at the same time, you'll need identical batteries within 6months old from one another. If you'll be using an isolator, you'll need to be sure all 'trunk' batteries are identical, within 6months old from one another. Will you be using the stereo for *extended periods of time with the car off? If so, the isolator is the way to go. In this case the batteries separated by the isolator may be different. If you'll only be listening to the system with the car on for the majority of the time then the isolator is not needed, BUT all batteries in the car must be the same, within 6months old from one another. ------------- 2013 Kia Rio -90a alternator
DDX470HD GTO14001 GTO1014D (x3)
Big3 in 1/0G
1/0G to GTO14001
Posted By: Alpine Guy
Date Posted: April 23, 2008 at 11:24 PM
What car is it?
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2003 Chevy Avalanche,Eclipse CD7000,Morel Elate 5,Adire Extremis,Alpine PDX-4.150, 15" TC-3000, 2 Alpine PDX-1.1000, 470Amp HO Alt.
Posted By: mylar
Date Posted: April 24, 2008 at 2:07 AM
Yes, I understand all of this about how they need to be the exact same for them to charge evenly... but say, what if I wanted to put a golf cart battery in there... is there any way to have 2 DIFFERENT KINDS of batteries and still have them charge evenly off the alternator?? (like ones a starting battery and the other a deep cycle battery) -the cars nothin special... just an 03 cavalier... lol, stereo was almost more then the car... but with gas the way it is, I cant complain
Posted By: daboss593
Date Posted: April 24, 2008 at 5:01 AM
you could always yank the ac and go dual alts?
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OWWWWWWWWWWW you said you discharged the cap!
Posted By: boogeyman
Date Posted: April 24, 2008 at 7:55 AM
i would look into dual alternators..............try h.o. alternators,see if u can give them a buzz
Posted By: Alpine Guy
Date Posted: April 24, 2008 at 8:03 AM
Contact this guy:
Iraggi Alternator
121 Highland St.
LaVergne, Tn. 37086
615-287-7991
He makes some of the best HO alternators that put out a lot of power at idle. He can pretty much make anything you need, as long as theres space to cram it in.
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2003 Chevy Avalanche,Eclipse CD7000,Morel Elate 5,Adire Extremis,Alpine PDX-4.150, 15" TC-3000, 2 Alpine PDX-1.1000, 470Amp HO Alt.
Posted By: daboss593
Date Posted: April 24, 2008 at 8:44 AM
if this is a 6 banger you may have room on the bottom side of the motor? you would still have to make a splash cover but they are not hard to make. Alpine Guy do you have an addy for the above alt guy?
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OWWWWWWWWWWW you said you discharged the cap!
Posted By: mylar
Date Posted: April 24, 2008 at 9:35 AM
Yeah, I've heard of a guy around where I live that re-wires alts... so I was thinkin of having him re wire a stock alt so it'd be able to fit under my hood... and nope, my car's only got a 4 banger but theres not much room any ways... see, I was told like 2 years ago, that there's something exspensive that monitors which side (battery) is low and distributes the power created by the alternator to the low side, thus both batteries charge evenly.... I dont remember what it was called or anything like that...
Posted By: haemphyst
Date Posted: April 24, 2008 at 12:29 PM
We seem to not understand Ohm's law very well...
THEY WILL CHARGE IDENTICALLY ANYWAY. Thank you, Georg Simon Ohm, for explaining this phenomenon for us!! (Yes, it WAS named after a real person.) Whether connected to the alternator through an isolator or not, they will only charge as needed, and identically. The purpose of the isolator is to prevent them from DISCHARGING equally and identically.
You need an HO alternator. I do not recommend rewinding the stocker, what happens if it dies, and you need another alternator right quick? IT DOES HAPPEN, AND YOU'LL BE STUCK. Buy a purpose designed HO product, something built for the duty.
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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: mylar
Date Posted: April 24, 2008 at 12:56 PM
i understand ohms law to a degree... but what i dont understand is how will 2 different models of batteries (red top and blue top) charge equally?? when they each have different ammounts of resistence (ohms)??? and i understand what an isolator does... i was thinkin about putting each battery on its own isolator and putting a switch on the remote turn on wire (accessory) to the isolators so i can control where my alternator is pushing its power to.... but i was wanting something much more automatic.... can someone help me??? dont forget i'm talking about 2 different batteries... not the same!!
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