Do I need a cap??

[SlimJim1284]

Ok I have 2 10" MTX thunder 6000's, a kicker 400.1 amp and I want to get an in dash dvd unit (and since I have monsoon, I heard I will have to get some adapter shyt to make it work) Will I need a cap??
If I do then I got two questions: where/what do I get and how much do they weigh??

[FireFighter]

do your light flicker? they are only maybe 3lbs for a 1 farad cap, and any audio place should sell them.

[camaro_speedemon]

Go battery, it's so much better than getting a cap IMO. If you feel you really need a cap, then get both.

[AllTheGoodNamesAreGone]

batt.. then alternator.. then cap..

[96firebird311]

I'm gonna have to disagree with the two previous posts. If you have slight dimming problems, a cap may be your solution. Should be about $75 bucks for a decent one. If you have moderate to extreme dimming problems, then a high output alternator is a must. Look for one that is high output AT IDLE! That is the key for a daily driver. I could hook you up with one that does about 140amps at idle and 190 max for probably around $250. Stock output is 105amps max. A battery is useless when the car is running. Let me say that again for the other two people... MULTIPLE BATTERIES ARE ONLY FOR WHEN THE CAR IS NOT RUNNING! More batteries will only allow your system to run longer while the alternator is not charging. With only a 400WRMS amp.... a cap should be plenty.

[AllTheGoodNamesAreGone]

<blockquote>quote:</font><hr>Originally posted by 96firebird311:
I'm gonna have to disagree with the two previous posts. If you have slight dimming problems, a cap may be your solution. Should be about $75 bucks for a decent one. If you have moderate to extreme dimming problems, then a high output alternator is a must. Look for one that is high output AT IDLE! That is the key for a daily driver. I could hook you up with one that does about 140amps at idle and 190 max for probably around $250. Stock output is 105amps max. A battery is useless when the car is running. Let me say that again for the other two people... MULTIPLE BATTERIES ARE ONLY FOR WHEN THE CAR IS NOT RUNNING! More batteries will only allow your system to run longer while the alternator is not charging. With only a 400WRMS amp.... a cap should be plenty.<hr></blockquote>


right.. keep thinking that..

EDIT:
man f-this.. here comes a rant..

ok.. think about how you run the lines for your stereo.. off the batt right?? if that dosent affect it, then i dont know what does..IMO i can crap in a bottle and call it a capasitor and you can give my 75$.. you will be better off.. you can talk all the theorherical electon engening BS you want.. but i will tell you.. nothing beats a battery.. yellow top = $150.. best money you can spend..

I have been buliding stereos for about 7-8 years now.. I just finished one for a friend pushing over 1500 watts.. and we dident even waste our time with a cap.. its not worth it.. and with the numbers that that amp puts out and the other gear you are gunna need more then a cap..

anyway.. bottem line.. dont be suprised when your lights start dimming with that cap.. and you have a $75 paper weight..

[ July 21, 2003: Message edited by: AllTheGoodNamesAreGone ]</p>

[camaro_speedemon]

<blockquote>quote:</font><hr>Originally posted by 96firebird311:
battery is useless when the car is running. Let me say that again for the other two people... MULTIPLE BATTERIES ARE ONLY FOR WHEN THE CAR IS NOT RUNNING! More batteries will only allow your system to run longer while the alternator is not charging. With only a 400WRMS amp.... a cap should be plenty.<hr></blockquote>

Please shut up, because you have no effing clue what the hell your talking about. My friend is pushing about 5000 wattsRMS, and he has 3 batteries in the back of his truck, and 0 caps and he has very minimal voltage drop. He knows what he's doing. Caps are only good for one or two powerful hits, that's all. If you're pounding your stereo at full volume a cap will not help your voltage problem, your drawing power faster than the cap can charge.

And let me explain something to you. Our stock alternators put out 105A. Tell me genious what happens when you excede 105A? Well, I'm gonna tell you, if you're drawing 120A, it's gonna draw he extra power from your batt. And do you even realize how much a 140A alternator costs?!? Be prepared to spend some serious money.

I've been working with car stereos for 5 years, and have a lot of friends that are into stereo competitions. I may not know everything, but I know that caps are pretty much a waste of money IMO.

Oh yea, check your battery before you go adding more batteries, caps, alternators. I had a serious voltage drop issue, than I relized that my battery was fried. I replaced it and have 0 voltage drop. And I'm pushing about 600W RMS on a NON CLASS D amp, which is a power hungry amp. I have no extra batteries, no cap, no upgraded alt.

EDIT: Oh yea, and if you wire up that cap wrong, just hope you have fire insurance...

EDIT2: And 400W shouldn't need ANYTHING.

[ July 21, 2003: Message edited by: camaro_speedemon ]</p>

[96firebird311]

I'm not gonna fight with you "experts". If you would like me to pull up some reading material for you two, then I will. And I'm SURE I can find a dozen other people to back me. Maybe pull up a couple old topics? You can't argue with physics. Sorry. :(

EDIT: Slimjim, if your in the market for a H/O alt. lemme know. I told you the deal I could get. They're not nearly as expensive as some may think.

[ July 21, 2003: Message edited by: 96firebird311 ]</p>

[AllTheGoodNamesAreGone]

"and he has 3 batteries in the back of his truck"

why isent he running caps??

BECAUSE THEY SU*K!! thats my whole point *** ..

with all that gear he has i gaurnetee you a 1-2f cap wont cut it..

[HotWheelz]

<blockquote>quote:</font><hr>"and he has 3 batteries in the back of his truck"
why isent he running caps??

BECAUSE THEY SU*K!! thats my whole point *** ..
<hr></blockquote>

If you're running 5000 Watts, then yes caps aren't going to do you any good. But to me, running multiple batteries for a system running just a couple of tens and a 400 watt amp is one thing....overkill!

So, Slimjim, speaking from PERSONAL experience, a cap should do you just fine. Before I bought the amp I have now, I was running two 12" Audiobahns off of a 600 Watt Kenwood, and I noticed I would have a slight dim in my lights sitting at a stoplight and such. I bought a small cap, and that fixed the problem right up. So don't try and tell me that a cap won't do me any good with a 400 Watt amp, when mine was bigger. So I'd say a couple farad cap should do you just fine, and probably end up running you less than an extra battery.

On the other hand, if you ever plan on upgrading to something with more power, buying another battery might be a good idea to save you money in the long run. But if you plan on keeping what you've got, go with a cap.

[ July 22, 2003: Message edited by: HotWheelz ]</p>

[camaro_speedemon]

<blockquote>quote:</font><hr>Originally posted by 96firebird311:
I'm not gonna fight with you "experts". If you would like me to pull up some reading material for you two, then I will. And I'm SURE I can find a dozen other people to back me. Maybe pull up a couple old topics? You can't argue with physics. Sorry. :(

<hr></blockquote>

Dude, are you stupid? If you have your system turned up all the way, then a cap is as useful as a umbrella with wholes in it. I'm no electrical engineer, but here is the basics on how caps work.

If you're listening to a song at half volume, then you get one low note that requires an instant increase of power, then yes a cap will prevent voltage drop because it has the power the amp needs imediately available. Then it will have time to charge back up for that next note.

Now if your listening to a song at full blast, then the cap is gonna supply that 'extra power' it has for one, maybe two seconds, then it's gone, your not producing enough power to charge the cap back up AND supply your amp with power. Once the power is gone, your relying on your battery and alternator to provide sufficient power. Caps only act as a buffer they can only do so much.

Think of caps like the anti-skip on your portable CD player. Yea it prevents it from skipping for a few seconds if you shaking it. But you keep on shaking it, your expending the buffer memory in the CD player, and eventually you're gonna run out and it's going to skip. Have I simplified this enough for your little mind?

Ok, one more time:
Caps are good for small bursts.
Batteries are good if you want to pound the **** out of your stereo and not have any voltage drop.

EDIT: One more reason an extra battery is good, you'll never really have to worry about having a dead battery. Go the extra $10-20 and by a deep cycle battery. Another friend of mine had his main battery under the hood die. It was probably dead for a good 2 months before he finally replaced it. You know why he went that long? Because he had a battery in the back that kept him going. Not something I really recommend doing, but you honestly won't have to worry about being stranded some where with a dead battery.

[ July 22, 2003: Message edited by: camaro_speedemon ]</p>

[96firebird311]

You two seem to think that I'm preaching on about caps. I'm not. For a small system and a small amount of headlight dimming, a cap is a cheap solution. Yes, for medium to larger systems they are useless. Everybody knows that. And they sure as hell don't supply power for even a second or two. We are talking microseconds here bud. There's no need to TRY to explain it to me. Here's a couple of old topics I dug up from ECA.
Topic 1
Topic 2
And here's one that I made especially for you guys! ;) Two replies from a mod and another well respected user. So please don't insult them or myself by saying that they don't know what they are talking about. :( And I'm done with this thread, and you two.

[CAMAROWITHBASS]

When playing your system really hard. Your lights dim because your
alternator can't keep up it's charging voltage (around 13.5V) and therefore,
demand exceeds output. When this happens, your electronic devices are
dipping into the power storage of the battery. Since the battery stores
power at ~ 12-12.5V, there is a 1.3 to 1.8V drop in voltage available. This
in turn is why your lights dim down.

HOW MUCH POWER DOES A CAPACITOR STORE?

1 Farad = 100 joules or 100W/second
850cca battery = ~2,200,000 farads

For storage purposes, you'd need ~2,200 1 Farad capacitors to equal the energy of your battery.

Due to its impedence (ESR & ESL), a cap's energy is only 50% available. What's worse, is that in order for a 1 Farad cap to discharge, first the alternator output must have maxed out, and the voltage must have dropped around 1.5 volts. But I thought a cap was supposed to prevent that (voltage drop)!!!!!????? Yep, you got the point.


IF A BATTERY = 2,200 CAPS, THEN WHY BUY A (PUNY) CAP?


SO, WHAT IS A CAPACITOR GOOD FOR?

1. Audio Jewelry- impress chicks with large cylindrical shiny thingy
2. Extra weight in winter time
3. A very POOR... BUT expensive distribution block
4. A projectile in the event of a crash
5. Rolling pin--for cooking purposes
6. A neat thing to tell your friend, "..Hey man, lick the top of this..

[camaro_speedemon]

<blockquote>quote:</font><hr>Originally posted by CAMAROWITHBASS:

6. A neat thing to tell your friend, "..Hey man, lick the top of this..<hr></blockquote>

[img]graemlins/rofl.gif[/img]

You forgot to add they are also fire hazards. [img]tongue.gif[/img]

[AllTheGoodNamesAreGone]

CAMAROWITHBASS,

that post was mint!
caps are ok for tiny little fixes..

but get a batt, and if that dosent help then an alternator.. yellow top all the way MOFO's..