IceCold2006

JL Audio 4300e 300W RMS Amp driving 4 alpine speakers
JL Audio 1400d 400W RMS Amp driving 1 JL 10" W6 sub
Alpine head unit
4AWG main power wire, 8AWG from distribution block to amps. 4AWG 2' grounds.


My battery voltage drops on bass hits and im only driving the amp at 3/4 output. Ive stalled my car on a red light while the system was up (at 3/4 output). Whats the best option on a tight budget, capacitor or alternator???

All opinons/experiences welcome.

Thx guys ^_^

Sonix

iTrader: (1)

capacitor won't do you any good.
You need a new alternator.

Go to a JY and grab a CS144 with the plastic fan on the front, from a 1995 Caprice, the 140A version. Snip the wiring harness and take that too. Wire that up, that'll work for ya.

Do a search on it, I asked that question a while ago and got that answer, it'll have more detailed specs for ya. I got the alternator in Canada (everything costs more here), for a whopping $50. I'll upgrade my charge wire for another $10 or so, done deal.

Gummie

Welcome to the forum

Screw the cap, get a bigger alternator. There was someone on the board who had the exact same problem as you a month or two ago but he was driving a lot more power. Install bigger grounds and you should be pretty much fine (that’s what he did). I'm driving about twice that on stock components (battery/alternator) and my lights don't even dim at night. The only thing I did was the 'big 3'.

The big 3 means upgrading your grounds (battery negative to chassis and battery negative to engine) and running a new power wire from your alternator to your battery positive. This fixes 90% of all dimming problems.

Here's a link with more info: SoundDomain.com Car Audio Forum: The OFFICIAL "Big 3" Upgrade Thread, With Pictures

Keep us posted.

Jim85IROC

iTrader: (2)

It's been said twice. Third time's a charm. Get a bigger alternator.

Formula3501989

I have to Agree a Better alternator is a good idea, But i also used 0-guage wires for my grounds and installed a 2 farad cap. My amp is rated for 1,800 watts rms, pushing 2 - 12 inch subs, and let me tell you it sounds like a stadium in my Formula. I am still using my stock alternator and my lights never dim at any volume, and my voltage guage never drops when the bass Hits.

Good Luck! and have a great day

Sonix

iTrader: (1)

hmm, is there an echo in here?

but yea, "the big 3", should be the first thing you do, also make sure the grounds are good and clean, use copper antiseize and or dielectric grease to keep things from corroding and to get a good connection. Those star washers are a good idea. If those solve the problem (only 700W RMS), then peachy, done deal. But I wasn't sure if you have a 20 year old 60A alternator in an '82 firebird, or a brand new 105A in a '92 Camaro (put your car info in the sidebar !!!!).

If the big 3 don't solve it, alternator time.

NEEDAZ

Me to, me to. I want in.
Yes, do the 'BIG 3', that should do the trick, if not, bigger alternator. Forget the cap.

IceCold2006

Well I shortened my amp grounds to about 1 1/2' (instead of 3') and stuck the distribution block right next to the amps (instead of 5 ft away). Its made an impressive difference and now (still running the sub at 3/4 for break in) battery voltage still fluctuates a little, but has no problem staying over 13V. This of course, on an idle.

Thanks alot guys . It just shows the laws of physics. The longer and/or thinner the wire, the higher the resistance, the more the battery has to work.
----------
Actually, thinking about it, would a cap be worth its money (in terms of sound quality, cuz thats all that matters in my book)??? If so, 1 or 2 farads? o_O

Gummie

Haha. The big 3 involves underhood grounds too. Click the link I posted earlier, it should improve things a lot.

IceCold2006

How big a wire do I run from alternator to battery, and ground to chassis??

Formula3501989

The cap i have is a 2.0 farad it provides the amp with 14.4 volts of power.
From my experience the cap is good if you want to give the amp more power.
But i also agree with the post above.. make sure All your grounds are good

IceCold2006

how am I spose to know if my grounds are good?

Ive noticed the stock alternator is rated for 100Amps, so it should be fine right?? o_O

NEEDAZ

Wrong, there are no 'volts of power'. Volts are volts (EMF) Power is current. Two related, but different things.

Wrong, but to long to explain. Search.

Because we said they're not. Not really easy to "test" a ground connection with equipment most people have. But if yours are stock, they're bad. Check the link Gummie posted for all you need to know about the BIG 3 upgrade.

*F-BodyFanatic*

iTrader: (2)

x - one more than whatever number of people already said this

Do the big 3 first. Use some 4g or 0g wire. That should help you out a little bit. Then after that, look into an aftermarket alternator. I'm sure there's threads on here about what to look for - but you can't go cheap in this area, else your idle output won't be that high, and you'll be right back where you started. Look into iragi alternators... this guy is good and warranty's his work. Not sure if his number is located anywhere on this forum, but I know its posted in a sticky at the sounddomain forums in the electronics section.

Anyway - cap won't do you much. All it does is just supply the amp with some quick power when the battery can't keep up. But if the battery/electrical system can't recharge it, then it to is pointless.

Also, if you're having a lot of draining problems, I'd consider getting a bigger battery - maybe an optima red or yellow top, or something of the like. They're deep cycle, so if you happen to drain it you're not doing as much immediate damage. But defintely do the big 3 and alternator first.

G'luck.

Birdman92

Your best bet is a battery. This comes from experience as a shop manager at a stereo shop, we have built a Bird hitting 150 dB stock alternator. A big battery from a company like Stinger will out perform the other options. All of the above will help, but I used to stall my beater at lights until switching batteries, now I have no problem. My vote would be with battery, then alternator. A cap isn't going to do anything for headlight dim, or your motor shutting off just help keep power to your amp.

Gummie

My vote would be for the grounds first. It's the cheapest thing you can do and it will only take you about 10 minutes. I did them all in 2 gauge wire and my light dimming completely disappeared with my stock alternator and cheapo energizer battery (I don’t think they even make them anymore).

If this doesn’t fix the problem then your charging system can’t keep up. Adding another battery might fix the dimming very short term but if your alternator can’t keep up with your electrical demands it was probably having a hard time charging the first battery and it defiantly won’t be able to charge both batteries and keep up with the power demands of the stereo.

IceCold2006

Problem solved. A bigger alternator was not needed. Stock 100Amps is plenty. I didnt do the big 3, although I probably will sometime. Ive already got a good battery (interstate), works fine. Turns out a cap did the trick. Its taking the hits instead of the battery and that is keeping me over 13 V at all times.

Birdman92

A GOOD battery will be a fix. I have ran my system for close to 2 hours near it's max while playing basketball and the car started right up when finished. I said nothing about a second battery, just replacing the stock battery with a battery from Stinger or another car audio battery (not optima).

NEEDAZ

Congratulations on spending way to much money on a band-aid that did not 'fix' the problem, but covered it up.

ScrapMaker

I had the stock alternator with the Yellowtop... 1AWG wire power/ground... never once did I see my lights dim, or the voltage drop below battery level with my 1300WRMS of power...


one thing people also don't seem to realize, is that most high-output alternators actually put out LESS amperage at idle than the stocker...

if you are looking for something to power your stereo while idling, like at a tailgate party, then you can look into a few high quality alternators that put out something like 90A @ idle...

remember: NEVER CHARGE A LOW/DEAD BATTERY WITH A-N-Y ALTERNATOR!! -- they aren't meant for it, and it can and will damage the alternator...

if you want to play your system with the car off, you MUST use a battery isolator setup... where the drained battery either DOES NOT get charged, ever, by the alternator, or there is an actual charging circuit that can regulate the flow without damaging the alternator...

Birdman92

Stock Alternator and 2200 rms from sub amp and 440 rms from high amp. Stinger battery has no problem keeping up. At an idle my voltage gauge on the dash drops on a good bass note but come right back up and the voltage gauge on the cap never moves.

ScrapMaker

as long as you have a good battery and adequate cabling, you have no need for a cap, and as long as you aren't playing your system all day, you really don't need a high-output alternator either... but it can't hurt

Xophertony

ok, in was reading this thread cause it sounded interesting (i was right). but now i have a question. i am not running big audio. just a little more draw then stock. i have NO electrical issues.... but i do occasionaly lend my alternators services to people with dead battaries by using jumper cables because i am a nice guy. am i harming my alternator by doing this? i have a 5mo old alternator. in that time i have probably given about 7 jump starts. (4 to my other bird). am i hurting my alternator?

Kestad9

Your hurting it big time if you let the jumpstarting car run that is for sure. If not, well it's not that bad. Many people don't know that when you jumpstart a car yours should be shut.

ringo234

Actually power = watts

Current = Amperage
Watts = Volts x Amps

Xophertony

i know now. thanks.

NEEDAZ

Good catch, don't not how I got that wrong. What I meant to say was
"Wrong, there are no 'volts of power'. Volts are volts (EMF) Power is current X voltage (P=IV) measured in watts. Two related, but different things."
Must have been a brain fart, good catch.

aaron7

iTrader: (7)

I always felt bad selling people caps when I worked at beast buy... as I knew they were just wasting their money! But, most people rather cover up problems than fix them... to each their own, right?

ScrapMaker

you shouldn't feel bad... if they're stupid enough to buy it... then so be it