D011AR

I am thinking to design my trunk and add another Optima in my trunk, and should I just connect the wire from the + on stock battery with the + on Optima? so the Optima can also be charge? or I need to do anything else? I saw alot of people have a extra batter in the trunk...please let me know...how u guys connect both battery? Thanx

Austin519

D011AR:
Why exactly do you plan on doing this? You can either just directly wire it...or put it on an isolater if you're running a large sound system...but either way you're not going to add much to your capacity...you'd need a rebuilt alternator like I have to actually change your power system output. Maybe if you explain why then I can answer better.

Austin519

kapsig1

I don't pretend to have the expertise of Austin, BUT, this is a topic I have some experience in. Austin is right, there's no way you can ADD a battery without adding 1) another alternator - good luck) or 2) a high output (or dual output) alternator. In addition, if you use two completely different batteries, without isolating them from each other, one will "feed" off the other. My experience with two alternators in a Honda product wasn't pretty. I had a competitive system in my Prelude that did indeed have two batteries: the car battery, and the system battery, which was a commercial elevator gel-cel (one bad muther). Eventually (after 10 months of tinkering) we wound up using a phoenix gold 170 amp alternator (only thing available at the time), a battery isolator and a giant relay setup that could completely remove the system battery from the charging chain (IASCA rule). It was a real expensive pain in the A%$! And we NEVER got rid of all the engine noise.

Bottom line, things have developed to allow you to upgrade the alternator and battery to run both the car and system with. If you're not going to compete (assuming IASCA still awards for the 2nd battery setup) and don't need the points, forget it. It's not worth the hassle, $'s and noise.

Brad

Austin519

kapsig1:
"There's no way you can ADD a battery without adding 1) another alternator - good luck) or 2) a high output (or dual output) alternator. In addition, if you use two completely different batteries, without isolating them from each other, one will "feed" off the other."

Sort of I mean you can by all means add another battery without adding an alternator. Then you'd more or less have a battery with the same voltage, twice the current output, and twice the capacity. My point was that it wouldn't do jack for your power woes if you were using more power than your alternator put out. That's why I upgraded my alternator. You also don't have to isolate them per se, unless you want to have a fully charged battery for ignition etc. Because the batteries will want to equalize and charge when they get depleted, and so will both act as loads on the system. Isolators are usually used when you want to have what you'd explain as a "competition" battery and a "car system" battery...one for each.

"My experience with two alternators in a Honda product wasn't pretty. I had a competitive system in my Prelude that did indeed have two batteries: the car battery, and the system battery, which was a commercial elevator gel-cel (one bad muther)."

Gel cell eh? I assume you used it because you didn't want the outgassing to kill you...aka it was in your trunk? Because gel cell takes more power to charge fully and doesn't deliver as much charge as a LiIon or PB battery.

"Eventually (after 10 months of tinkering) we wound up using a phoenix gold 170 amp alternator (only thing available at the time), a battery isolator and a giant relay setup that could completely remove the system battery from the charging chain (IASCA rule). It was a real expensive pain in the A%$! And we NEVER got rid of all the engine noise."

Don't even make me thing about IASCA regs! Uggghhhh.....

"Bottom line, things have developed to allow you to upgrade the alternator and battery to run both the car and system with. If you're not going to compete (assuming IASCA still awards for the 2nd battery setup) and don't need the points, forget it. It's not worth the hassle, $'s and noise."

Even more...it's not worth it ever really...unless you've already upgraded your alternator and need to find a way to get a few minutes more power out of the system (me)...

Austin519

kapsig1

<<Gel cell eh? I assume you used it because you didn't want the outgassing to kill you...aka it was in your trunk? Because gel cell takes more power to charge fully and doesn't deliver as much charge as a LiIon or PB battery. >>

Yup! It was in the trunk, didn't feel like gassin' the judges, although sometimes felt like it. The gel didn't have much in terms off CCA's but it had a HUGE reserve and actually operated at 13.3v when NOT connected to the alternator.

<<Don't even make me thing about IASCA regs! Uggghhhh..... >>

No kidding, don't have many fond memories....except when I took home 1st.

<<Even more...it's not worth it ever really...unless you've already upgraded your alternator and need to find a way to get a few minutes more power out of the system (me)... >>

I agree totally for a "daily " user. We put my setup together, because at the time it was good for an extra 40 points in IASCA, and my system was designed for sound quality, and I would lose a good 5-10 points against my competitors for only hitting 130 DB. But foe the day, it did sound sweet.

Brad

PS - appreciate the knowledge on this board!

Mr.T

I've been keeping up to date about austin altenator but I still notice you didn't put up a price. I'm running a backup battery with a isolator. I figure my altinator will die out pretty soon cause it was giving me 14.1 for both battery for like 3 months but now it's at 13.6 so it's dying slowy LOL. Still looking for a altenator I figure when mine dies out I could get a aftermarket but than I'll probably blow out my subs I love SPL but it sucks in our TL WORD :p

mR.t

Austin519

Mr. T:
The final price on that alternator upgrade was $450. As for the backup battery and all that, depending on the size of your system it won't do much for ya. As for the alternator dying out...it's not like a battery...you won't see 14.1...then 13.6...then 13.1...then it just dies...it has an internal voltage regulator and if it's going to die, it will just die...no warning or anything. So be on the lookout dude

Austin519

bebber

If I can toss in my two cents....

Adding another battery will allow you to run your system longer with your engine off and still be able to start your car. This is assuming that you run your car long enough before hand to keep both batteries charged. Not that this is too useful anyhow, cause you'd probably want to only play your system when the engine is on. What would be more useful is that the extra battery will better supply temporary surges of power that you sound system might demand, placing less stress on the alternator and extending the life of the alternator.

Bottom line, if you're noticing that you're not getting enough power, you really do need to upgrade the alternator as Austin has often suggested. You can either replace the alternator with a higher output version (is there one?), add on an additional alternator onto the pulleys (is there space in the engine bay?), or get the stock alternator rewound for higher output (like Austin did).

I don't know much about car audio, but this is derived from what I know about electronics and circuits.

Austin519

bebber:
Quite true...assuming you're not pulling a lot of current, and then it's over.

"What would be more useful is that the extra battery will better supply temporary surges of power that you sound system might demand, placing less stress on the alternator and extending the life of the alternator. "

That's true too to some extent. But the whole point of a capacitor in the stereo system bebber is to supply those boosts of power. The problem with powering a large system is not that there's not a lot of power available (there are HUGE quantities of power available in a car battery)...it's that the car battery can't instantaneously discharge it (it depends on the electrochemical reactions in the battery, and that coupled with the internal resistance makes it impossible). There's few things more powerful than the breakdown of a large electric field, and that's why a capacitor works so well for this (bebber I guess none of that was for you, you know all this).

So I guess the best way to say it, is that an extra battery will better supply small, temporary surges of power that a small stereo system will demand. As for extending the life of the alternator...that's a bit iffy bebber. All our alternators are, are voltage regulated generators...they're pretty independent of how much draw is required...in terms of how long they live. Granted, the internal components will last longer with less voltage applied to them, it's just the nature of the components...but it won't be a noticeable difference.

But I guess I should also say...bebber you're absolutely right . I guess just not maybe on the scale I'm thinking of stereo.

"You can either replace the alternator with a higher output version (is there one?), add on an additional alternator onto the pulleys (is there space in the engine bay?), or get the stock alternator rewound for higher output (like Austin did)."

There is a higher output alternator available...but it's the equivalent of a rewound stock alternator...and is actually lower quality and more expensive. Our big problem is space...much like most houses in Japan, our Japanese cars don't have much room to move around in . So to get more output you need to 1) install a second alternator 2) get a large case alternator (more copper windings inside = more power) 3) rewind the stock alternator tighter with more copper (more copper = more power). The first one definitely can't be done. No room. The second can't either because there's no room around the stock alternator to do this. So the only choice is #3, which is what I did.

Bebber I think you've just proved that electronic circuits knowledge ~ car audio knowledge

Austin519

bebber

Thanks for the vote of confidence Austin.

About the battery extending the life of an alternator, I just think that this is the case because I've heard about alternators failing in cars that have weak/dying batteries. It's as if the alternator has to accomodate for the varying power demands in a car more vigorously if the battery isn't there to help smooth out the voltage changes.

BTW, those 1 farad capacitors in audio systems are huge! That might be enough charge to kill a man. If anyone has caps, I hope the terminals are well insulated so you don't accidentally touch them while reaching underneath a seat or in the trunk. At very least, touching a fully charged 1 farad cap would cause severe pain.:wow:

Austin519

bebber:
I've heard the same...about weak/dying batteries and the alternators...but it's a cause effect thing...and I think that probably those batteries are weak/dying in the first place because the alternator's going bad. Because the battery really doesn't do much to smooth out the transients in the power supply. Yeah those 1F caps are big...I'll be running 3-6 of them . 1F sure is enough to kill a man, but I've been hit with one before, not completely charged...the problem is that the cap can't conduct across the body fast enough...so not enough current = you don't die. But 3-6F can conduct enough across the human body...and I hope I never find that out. My old physics Prof. who taught me all the background to power systems back in 9th grade told me the story of a student of a Professor friend of his building a huge capacitor out of aluminum foil and wax paper laminated together, and he ended up killing himself so well...

But yeah...touching that cap did more than cause severe pain...it knocked me flat and made me throw the capacitor across the room...haha to my brother it looked like I just threw it across the room and crumpled on the floor. Whew...

Austin519