Batteries

[87gnblackdemon]

I've always been curious about running a seperate battery for my system. How would I do it? Do you use both , the factory and second battery? Do you hook the second battery to anything, or just run off it?

[ITSAV6]

You can wire them together but they make a battery isolater that charges both batteries but the stereo only runs off the extra batt. You can sit w/the engine off and kill the aux battery and still crank the car!

[Audiowizard]

You need to run a battery isolater to keep them from constantly drawing off of one another. You will also need a new wiring harness for alt. that has a current sensing wire so you can charge both batteries seperately.

[HzEmall Regal]

You can isolate your 2 batteries by simply using a Dual Battery Solenoid. Using an isolator is usually not a good idea because of the voltage drop you can have across the diodes inside.

You don't even need any special harness's for your Alternator, simply run a positive cable from your stock battery to a solenoid then the other side goes to your second battery. You wire the activation wire to your ignition so that the 2 batteries are only connected while the car is running.

You should try and get the main and second battery to be close to one another in size and type to avoid any problems.

Hope that helps

[Audiowizard]

Originally posted by Xtant Regal
Using an isolator is usually not a good idea because of the voltage drop you can have across the diodes inside.

I disagree because I have measured voltage off of my isolater on both posts with engine at idle with no virtually no difference between alt. output readings (but then again, I have a high out-put alt).


You don't even need any special harness's for your Alternator

Not totally true if you are running an isolater. when I ordered my battery isolater, the company that I ordered it from supplied me with the correct harness for my alt. With out it, it wouldnt charge my main battery correctly because I tried it with out the harness mod.

You can use the solenoid trick to charge both batteries but that is the cheap way out and I chose not to cut corners with my electrical system. Not trying to bash your statement Tim but this is from my own personal experience with 2 vehicles that I have built with the same GM alt.

Gary biggs is the one that supplied me the info for both my vehicles a few years ago so you know I was getting good info from the IASCA and USAC World champion.

[GNandTTA]

I tried both and at least for me the solenoid workes better. Although I never had the mod trick to raise the alternator voltage to compensate for the voltage drop. An added benefit for the solenoid - you can wire up a momentary button switch activate the solenoid. Gives you double the starting power on those extra cold mornings.

[zam70]

Gotta go with the solenoid on this one. I've tried the isolators and the relay type and have had much better (and reliable)results with the solenoid.

Cheap does not always mean not good...

The isolator type runs current through diodes, NOT good if you're in a high current situation.

To setup a dual bettery system correctly, use the same gauge wire between all devices in the chain (batteries, alternator, isolation relay and grounds)
All batteries have to be of the same type, age and size, preferably brand new.

hook the trigger wire up to an IGNITION wire, not accessory. Better yet, use an RPM activated switch to trigger the relay. You only want the batteries connected together when the engine is running. Aux ground the body, chassis, engine and battery.

and that's about it. I've used this setup with as many as 20 batteries on the stereo side and it worked flawless for years.

The real question is why do you want dual batteries. If it is to have extended play time with the key off with out running down your starting battery, good idea. If it is to supply more current to the stereo system, bad/useless idea.

If you need a better current supply for the stereo the ONLY real solution is a bigger/better alt.

Audiowizard: To me using IASCA/USAC to enforce an original comment actually discredits it some what (at least to me...) those organizations were put together as a sales devices. Therefore alot of what they preach is sales influenced. Not challenging your personal experiences, I respect experience alot more than words. If a dual isolator works for you great...but I have installed thousands of systems with hundreds using the relay and had zero problems, Of the few that did initially want a dual isolator eventually ALL switched over to the HD relay setup.

just my .02, no disrespect intended.

[Audiowizard]

Originally posted by zam70

Audiowizard: To me using IASCA/USAC to enforce an original comment actually discredits it some what (at least to me...) those organizations were put together as a sales devices. Therefore alot of what they preach is sales influenced.

HEHE that was me just being sarcastic about the IASCA & USAC thing. Its an old joke between me and Gary (I should have elaborated) Those organizations where put together primarily for the sales in car audio so I totally agree with you on that statement.

Using the solenoids do work for the use of dual batteries but I like and prefer the battery isolater which has worked well for me for 11 years and some routines are hard to break .

[HzEmall Regal]

Zam70.........damn man.......you beat me to it

Audiowizard, you may like Isolators, but you have obviously never dealt with a car or RV after one of those diodes opened up and nearly fried the whole car.

While you can start the car and test for a voltage drop across the terminals and have very little drop(any drop is bad), try it after driving the car for a few hours..........it will amaze you how much loss there is once those diodes get warmed up. A melt down with a Isolator is even more dangerous when you have a high out put alternator do to the increased current your dealing with.

[zam70]

Originally posted by Audiowizard


HEHE that was me just being sarcastic about the IASCA & USAC thing. Its an old joke between me and Gary (I should have elaborated) Those organizations where put together primarily for the sales in car audio so I totally agree with you on that statement.

Using the solenoids do work for the use of dual batteries but I like and prefer the battery isolater which has worked well for me for 11 years and some routines are hard to break .

OHH..ok, sorry...didn't initially get the sarcasm....AND I am a true believer in doing what works for YOU. Obviously, you are and it is working great for you. Either way I believe the original question has been answered from both sides of the fence. He definately has the info he needs no matter which device is used!

[87gnblackdemon]

The reason I ask is because the car sits for good amount of time between starts, I usually on run it on the weekends and sometimes everyother weekend, and I've had problems with my battery dying, figured it was from all the gadgets I have hooked-up, scanmaster, radar detector, two amps, on and on, and that my headlights dim when the bass hits, not real bad, and I don't mind It, but I figured using a seperate battery for just the stereo equipment would cure this and each battery wouldn't be supporting so much.

[mcss383]

the only thing is, when you add a second batt then the alt has that much more to support......

[Audiowizard]

Originally posted by Xtant Regal

Audiowizard, you may like Isolators, but you have obviously never dealt with a car or RV after one of those diodes opened up and nearly fried the whole car.

I have never had one go bad (knock on wood ) So to prevent that problem from happening, I have all power wires fused from alt,front and rear batteries for safety. In the event that were to ever happen, I am safe from a electrical fire.

Either method described will work but the Isolater costs more than the solenoid which may not be cost effective for some. Good luck black demon. BTW, you never sent me the basket area volume of your CV sub for me to calculate that box for you. As soon as you find out, let me know.

[GNandTTA]

the only thing is, when you add a second batt then the alt has that much more to support......

Very true. I remember in the Autosound 2000 tech breifs (from Ricahrd Clark & David Navone) they mentioned that each battery, depending on size, adds between 15 to 20 amps extra CONTINOUS draw. That is quite a bit for doing nothing more than being there.

[HzEmall Regal]

Originally posted by Audiowizard


I have never had one go bad (knock on wood ) So to prevent that problem from happening, I have all power wires fused from alt,front and rear batteries for safety. In the event that were to ever happen, I am safe from a electrical fire.

Audiowizard.........fusing will protect you from a amperage spike.........not a spike in voltage.........that will still let the smoke out of everything..........The last motor home I fixed was well fused cause I told him how and where to fuse all his batteries, but he was dead set on keeping his isolator cause he spent $600 on it. Now he has a solenoid and lots of new electronic items in his motor home.....ohhh....and some new ford electronics too cause they went up in smoke.

[Audiowizard]

Originally posted by Xtant Regal

Audiowizard.........fusing will protect you from a amperage spike.........not a spike in voltage.........that will still let the smoke out of everything..........

True...but a bad alt. can also cause a voltage spike and fry your electronics just as much as a bad isolater. I have mine fused for direct shorts only. I appreciate the info anyways .

[be_regal]

Unless you are running some serious amperage I wouldn't even worry about running another battery, I was toying with the idea but decieded to just go out and get an Optima yellow top. When some serious lows drop you can hardly even see the light dim even just a little. They are a little expensive but, but you don't have to worry about wiring the other battery, finding a place to secure it, or the extra weight in your car if weight concerns you. In the long run it may even be cheeper to go this way. I have played my stereo with the car off for 20 minutes and had no problem firing it back up.

Just something to think about........

[zam70]

yellow tops I've had more problems with gel batteries...If anyone really wants one I've got one sitting on a shelf in my garage that you can have (came in my TR when I bought it...couldn't get it out fast enough) Regardless of what the manufacturer says, gel tops are NOT designed to start a car. You're definitly better off with a good ole lead acid battery...my preference is the duralast...

just my .02

[be_regal]

zam70

I'm sorry to hear that. I have had mine since last summer. It has nothing but alsome, if you really don't want that yellow top i will take it off your hands.

[HzEmall Regal]

Zam70.......Optimas are not Gel batteries, they are standard Acid batteries, read the following info on their site.

htt