Christos

Well, bad topic... I know they exist, such as Pheonix gold, and Stinger.

Right now, I'm not running too much power from my 300RMS amp, but even with it not running, my battery only stays charged if I drive about 6-8 miles at least. Any less, and my car won't start.

Battery is about 4 months old. Im currently running the ac delco 140 amp 1le alternator replacement too. It's about 2 years old, maybe 8,000 miles on it.

I have the TPI engine, which is a real power hog, one of the chevy mags did an article on this problem a while back even. Mine is worse, because I have my fan wired to always be on, (tried fixing it, can't figure out the electrical wiring, whoever had the car before me did something so crazy, myself and a two friends couldn't figure this out over a period of months)

My question, I found a chrome 140 amp alternator, <a href="http://yearwood.safeshopper.com/147/cat147.htm?543">Here</a> which claims 80 amps at idle. Is this higher then my current alternator?

Or is this a normal output for a 140 amp alternator? Does anyone know how many amps my current ac/delco 140 amp alternator might be putting out at idle right now?

I just don't want to buy another alternator which is the same as my current one. It doesn't sound like this alternator is the same, i doubt my current one puts out 80, but I wanted to check with you guys first.

Thanks for any help.

ramair350

Actually what you probably want is a CS or constant carge alternator which will carge at idle speeds. Most factory Delco alt.s only charge at 1800 rpm so at idle you won't get anything out of it anyway. You may want to check into an Alumapro power C.A.P. or the Stinger 5 farad cap as well they will take the load off of you charging system when the bass hits. I have done a few systems in these cars and all of them have had to do a cap of some kind.

mudaholic

80 amps at idle? i have never heard of an alternator beeing able to produce that. basically, the higher your max amperage is from your amp (ie you have 140), the less its going to charge at idle. if you're very concerned with your idle, you might want to get a smaller alternator, which will produe less amperage overall but more at idle speeds. another option would be to look into getting a dual alternator setup, but investing in a capacitor will be a complete waste of money for your particular problem.

ramair350

Why would a cap be a waste of money for him? They are designed to release power on demand so when the bass hits the power comes from the cap instead of the alternator. I have friends in the car audio business also that don't believe in caps either but it is kind of funny that if you look at all of the high end systems in magazines or even better go to USAC finals in Kansas City in Nov. and see that they all use a cap of some kind. The old thinking of using a 1 farad cap for every 1000 watts of power, according to Alumapro, isn't the right formula. You should be using a 1 farad cap for every 100 watts of power. I sold Monster Caps for years I even have one myself and I will admit that they are a pile of junk! But since I became an Alumapro dealer I have done systems that put out up to 2400 watts and are using the stock GM alternator. If your alternator only carges if you drive at least 6-8 miles even with your amp off then I think that you have more problems than your alternator. I would do a load test on the alternator and then see what whether something is draining that battery after the car is off or if the alternator isn't doing it's job. It is up to you I could care less if you buy a cap or not, I just know that people with the same problems have fixed it with a cap.

CAMp3RO

if you are not competing, you do not need the alumapro CAP, and even if you are, they arent the best choice. if you go look at actual car audio boards, you'll know why. they are pretty much useless (the original models, pheonix gold's new one is supposed to be better, but very pricey). and of course alumapro is gonna say the formula is wrong; they wanna sell there product. first thing, before you buy a cap, upgrade any of the stock 8ga under the hood to 4ga or bigger. this includes all underhood grounds, battery to alt, etc. next, that fan is gonna draw out a lot if its constantly running. caps are no means a fix for systems; they are band aids. try finding a higher output alt or getting your alt rewound at a lat shop to put out more power. if necessary, pick up a seperate battery (like an ultima yellow top or the like) and run a battery isolator. oh, and my last few systems have not needed a cap, and my current one is pumpin out around 600 rms.

ramair350

To each his own do what you want. Everyone will tell you different and you will never be able to change their minds.

mudaholic

nevermind, im not getting in to this discussion again.

CamaroDriver

There's two things about a GM alternator that makes it stop charging at idle.

One is a heat protection device. It only allows the alt to produce current after 1400 RPM so the cooling blades can actually move air into/around the alt.

The other is the regulator itself. If your battery is fully charged, and the demand for electricity in your car isn't higher than what the battery can put out, then the alternator will not charge the battery.

The alternator's job is to charge the battery. That's it. It's not there to provide electricity to the car. Once the battery has been drained to the point of not being able to produce AT LEAST 13.8V, then the alternator starts to supply more electricity to the battery.

The real way to totally eliminate the problem you're having is to buy another battery and hook it up along with your current battery.

And a cap is not made to do what the battery does, nor aid the battery in any way. It's main purpose is to provide QUICK electricity. Example..... If you lay a wrench across the battery terminals, it sparks, and usually sends the wrench across the room. But if it stays there, it will continue to heat up because the battery will continue to drain until it's either dead, or the wrench is removed.

If you lay a wrench across the terminals of a capacitor, it won't send it across the room. It'll send it across the HOUSE!!! But if you do leave it there, while the cap is not hooked to the battery, it won't continue to discharge slowly. Once the electricity has found a way out of a capacitor, it's gone. There's no slow discharge like a battery.

Since a battery has a slow rate of discharge, it has trouble keeping up with the demands of the amplifier. If you run a string of continuous beats at 60hz, for 30 seconds at 2 beats per second, the first 4 beats will sound strong, then they will slowly trail off and become weaker.

The cap "helps" eliminate that, but it still requires current from the battery to keep itself charged. So as you can see, it's ALSO drawing current from the battery. But since it has a quick discharge rate, it also had a quick charge rate.

The neat thing is that it can also keep the battery up on it's feet by providing it with instantaneous power as well. Think about it, a cap is hooked to the amp AND the battery. Whichever one needs the 'instant' electricity will get it. It just depends on which one needs it more.

That's why a cap usually helps with making music sound more crisp and accurate. They discharge a lot faster to provide the amp with the electricity it needs NOW!!!

Huckster's '84 TA

this may sound simple, but is you current battery good? it might not be able to hold a solid charge. i would think only 300 watts should not drain your car like that, even with the fan always wired on. i know people that have over a thousand rms watts off their stock charging system and idle it all day. just a suggestion.

mcss383

2400w on a stock alt.....thats nothing, the whole idea that you need 140, 180A alt's is a bunch of crap, you're NEVER pushing anywhere near that power with music for more than a millisecond or so. BTW, alumapro caps (the C.A.P.) are useless. When current is drawn across them they cause a larger voltage drop than just the amp would due to their high ESR (equiv. series resistance). Simple physics really, V=iR, a large resistance with a large current draw means a large voltage drop....which isn't good.



Look at what Hukster is saying, get your battery checked out, if its going bad it will be drawing tons of current to keep it charged, with it drawing all the current there isn't much left for the amps, thus you have voltage probs.

Christos

Good points, and thanks.

I had to jump my car when I picked it up, (didn't disconnect the battery for the 5 months it was in stroage, doh'!) but I did drive 1100 miles on it, for my triop. Figured a new discharged battery would be able to charge back up again.

I hate to spend 200 bucks on a yellow top deep cell (we all know the brand) and just have it last a month, and die like this battery did.

Haven't been running my stereo for the last few days because at idle, my voltage shows about 12 volts on my meter, unless im at about 3K and up, then it goes up to 13-14. (much less with music on)

I figured a good high-output alternator might solve this, as my battery would be getting the juice it needs at idle/low rmps to charge it up.

Ive heard the same for the caps too, "1 per 1,000 watts", my a§§. The 1 for 100 rms comment sounds more true. Just because my system can't seem to stay charged even with the stereo off makes me wonder though.

I'll think about a new battery anyway. I'll post again with what happens.

White Ninja

i've seen caps come in .5 and 1 farad... they suggest 1 farad per 1,000 watts.... i've never needed one, my music is fine and it doesn't really fade the interior lighting either. I'm thinknig about getting a battery and a .5 farad cap and hook it directly to the amp... this will take all demands off of the car's electrical system, so it can use all the energy it so desires. getting a couple good batteries is a great thing, and it probably won't cost as much as a $200 yellow top. BUT this only works for me because i have a battery recharger, and it also sucks when the battery drains out......(no bass)

mcss383

Hooking a battery up to amp WILL NOT take away the demands on the electrical system, it will add MORE demands!!

Think about it, whats going to keep that second battery charged? The alternator. What source is the amps pulling from when playing (and the car running), the alternator. Only when you drop the entire system voltage down to 12V or so does the battery contribute ANYTHING to the amplifiers. The source of higher potential is always the source of power.

Christos

That's what I sort of figured. Don't you need some kind of 2nd battery isolator, and some kind of alternator output splitting thing to charge both?

mcss383

That helps yes, but you still have yet another battery to charge, which does mean less (although not a lot) current for your amps. The only need for additional battery's is for car-off listening and serious SPL competitors. With SPL competitors they are drawing insane amounts of current and their voltage WILL and DOES drop to 12V and lower, so they need as many batterys as they can get to MAINTAIN that 12V and not drop lower...but for us everyday commuter car audio people we don't see any benefit from an additional battery (unless you are doing lots of key off listening, like on the beach or something).

Huckster's '84 TA

with only 300 watts, i'm sure just a standard new battery with be more than enough. do that first and if a new battery doesnt fix anything, you can decide on the next move. either way, you should replace it.

BadMunky87TA

just out of curiostiy, what kind of amp(s) are you running nad what size wire?

Christos

Well, ran out and checked things out. My voltage was showing good today oddly enough.

I used a little analog meter my roommate has, and my battery checked at 12 volts, and with the car on, voltage showed almost 14 3/4 volts at the alternator. From what I know, that's good.

No way to get watts though, too bad, that was the reason I was testing it, I wanted to do the math to see the idle amperage my alternator puts out. Need watts and volts to do that though. Shoot.

As for the wire to the alternator power, it looks stock enough. eyeballing it, I would say it's 12-14 gauge.

White Ninja

no guys, this battery will not be recieving any input from the alternator, the alternator will be strickly for the battery for the car, the second battery will be in the back with the amp, and the amp + and - hooked directly to it. it'll work, the amp get the power from a source, it doesn't care where, and it gets audio input from the receiver... so it'll work.

mudaholic

are you kidding? how do you plan to keep the battery charged? plug your car in every night?

mcss383

It will work for maybe 10-15min depending on the battery's capacity....I suggest you spend some time researching about electricity....