Capacitors and other ideas
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=30800
Printed Date: April 26, 2024 at 2:27 PM
Topic: Capacitors and other ideas
Posted By: casedeez
Subject: Capacitors and other ideas
Date Posted: April 21, 2004 at 2:09 PM
Hey guys, First post here. I am installing 4 jl 12 w3 d4's into my 98 dodge dakota. Im going to be running them off of two kicker zr 360's. I couldnt find what spec my alternator is but ill be working on that here soon. I have the tow package so im guessing its at least 130 amp. Anyway with the system im going to be running what size capacitor would you recomend running? Or would you do something different? Keep in mind Im on somewhat of a tight budget and would like to do this the cheapeest way I can. From what ive found a capacitor is a capacitor, so if you think otherwise let me know caps you would recomend. Thanks
Replies:
Posted By: DYohn
Date Posted: April 21, 2004 at 2:27 PM
Realize that caps won't help you if you have too small an alternator, so if you need to upgrade it, do that first. Caps can help your amps sustain peak output levels, but can't help with weak electrical systems. Caps are caps, for the most part. When comparing, look for ones with lower ESR ratings. ------------- Support the12volt.com
Posted By: casedeez
Date Posted: April 21, 2004 at 11:36 PM
Ok now say, Im running two kicker zr 360's. max output is 800 watts said by kicker. However they can put out more power than that under the right condidtions. In any case Im going to be running two of them, what size alternator should I use? From that point what size capacitor should I use? thanks
Posted By: bfog99
Date Posted: April 21, 2004 at 11:51 PM
With what i found about those amps, you probably will not need a high output alterator. The highest rating I saw was 360 watts RMS x 1, but you will have 2 amps, so 720 watts RMS. That will draw roughly 56 amps. If you have a 130 amp alt as you stated, you have plenty of room.
Posted By: casedeez
Date Posted: April 22, 2004 at 12:01 AM
On the birth certificate I have here of the amplifier, it states that the amp ran at 477 watts continuosly and this was at 4 ohms. Imagine the possibility of running this same amp which is stable at 1 ohm stereo and 2 ohm mono at either one of those. I would be drawing more than 360 watts. I realize they could have ran the amplifier at 14 volts but as any kicker enthusiast knows the amps kicker makes or at least the zr series was severely underrated. The amp is a beast and can push more than what kickers saying. Just for kicks If I am running with 720 watts and my alternator is roughly 130 amps, where would I be ok going with just a farad capacitor? On a side note I had a honda civic si which I believe that the alternator on it was at least 70 amps. I had the amp 2 12's and a farad cap hooked up and I was still getting the dim light deal when the bass hit. Is there another explanation? Thanks for all the help
Posted By: haemphyst
Date Posted: April 22, 2004 at 12:32 AM
This is a canned response to everybody for the next week that asks if they can "fix" their problem with a new battery, another battery or caps... DYohn and forbidden and I have been trying to get people to realize this for ever. Your alternator is too small. You have to upgrade it. I din't care how many caps you put in your system, it will not fix a low current supply condition. Even if your alternator is rated 70 amps (and I think it is probably smaller than that, being fairly familiar with many things Honda - I have an LX with power everything, and mine was only 55 amps) that is only 1008 watts being supplied by the alternator. AC will draw somewhere in the 25 amp range (360 watts) your headlights are around 5 amps(70 watts, on low beam 110 on high) clearance lights will pull a total of 8 amps (115 watts) brake lights 2 amps (30 watts), the engine just running uses 9 amps (130 watts)... 1008-360-70-115-30-130=303 watts. How you gonna run a 700+ watt amp with only 303 watts? Do you see where all this is going? Your alternator is too small! A cap will not magically "make power", it just gives you power in different ways i.e. high current for short periods of time, but when it is empty, it is just another load for the alternator to supply power to. Also, a class AB amplifier will NEVER be 100 percent efficient, 50-75 percent is more like it, so, if you are putting out 700 watts to the load, you are also blowing off 350 watts in the heatsink, for a total of 1050 watts or 73 amps! You can not forget that an electronic device is NEVER 100 percent efficient. If that were the case, there would be no such thing as heatsinks, because there would be no heat. If your lights are dimming, you need more alternator. There is NO OTHER WAY AROUND IT... not caps, not batteries, not battcaps, A-L-T-E-R-N-A-T-O-R.
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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."
Posted By: speedwayaudio1
Date Posted: April 22, 2004 at 12:46 AM
haemphst, and DYohn could not be any more correct. Caps are cool to look at. They do help when you have plenty of current feeding them. Get the alt. To find out what amp rating your alt has call a parts house and ask them to look it up for you. GET the alt.
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Big Dave
Posted By: casedeez
Date Posted: April 22, 2004 at 1:41 AM
haemphyst- Thats what Im talking about. That information you gave me is pretty much what I was looking for. It explained a heck of a lot to me. I appreciate it. On the other hand I did not have a problem yet. All of my stereo is sitting in my room waiting to get put in after I build the box. In the mean time I am getting all the information I can to make the system as flawless as possible. Instead of blindly installing my system I want to work the kinks out before I install it. See, up here (Oregon) people all over the place happen to install whatever they buy right from the stereo store. Most people I know only have the knowledge of hooking up an amp and a couple subs. The really smart ones can bridge the amp. I was there once, however I am working on learning more. This is where this forum and other installers come in. I by no means know everything. The information you gave me was excellent. It was detailed and answered a whole lot of questions. The information I knew previous to this was that a capacitor basically charges your amplifier rapidly. Other than that I was told "a cap will make it so your lights dont dim..." BTW the alternator that was in the honda which happened to be a 91 civic which doesnt come with may power options did not have the stock alternator in it. (Among other parts that werent original) Lastly, say I have to get a new alternator. Is there a brand/ place that I can go to and get a good alternator at a relativiley inexpensive price? On that note is there a way I can accurately caclulate the amperage I need from my alternator based on what I am using in the truck. IE amps, power everything, lights etc? Again thanks for all the help you guys have been giving up. Its truly appreciated.
Posted By: kickerstang
Date Posted: April 22, 2004 at 6:53 AM
YOU KEPT SAYING YOU HAVE A 130 AMP ALTERNATOR AND YOUR PULLING 720 WATTS, THE WATTS ARE NOT WHAT YOU ARE PULLING, YOUR PULLING AMPS AWAY FROM THE ALTERNATOR. LOOK AT YOUR AMPLIFIERS, HOW BIG AND HOW MANY FUSES DO THEY HAVE? NOW ADD THEM TOGETHER. NOW TAKE ABOUT 75% OF THAT, THAT PROBABLY CLOSE TO WHAT YOU'LL BE PULLING FROM THE ALTERNATOR. I HAVE A MA AUDIO HC1302, 130 x 2 @ 4ohm , 1300 x 1 @ 1/2 ohm, IT HAS 3 30AMP FUSES ON IT, SO YOU'D FIGURE IT PULLS 90 AMPS RIGHT? WRONG. I DID A TEST TO SEE ABOUT HOW MANY AMPS I'M PULLING, I REPLACED ALL 3 30 AMPS, WITH 3 20 AMPS AND CRANKED ON IT FOR A FEW HOURS, DIDN'T EVEN GET WARM. SO I'M PULLING LESS THAN 60 AMPS ON AN AMP THAT SAYS IT PULLS 90. ------------- what!?!?! you want some??
Posted By: flatulatta
Date Posted: April 22, 2004 at 9:04 AM
could you put bigger amp fuses in an amp 2 get a higher draw or will it fry the amp?
Posted By: DYohn
Date Posted: April 22, 2004 at 9:43 AM
flatulatta wrote:
could you put bigger amp fuses in an amp 2 get a higher draw or will it fry the amp?
NEVER change the fuse size in an amp! The fuses are chosen by the manufacturer to protect the electronics in the case of a failure, and to protect YOU and your car from catching on fire. If an amplifier fuse blows, there is something wrong with the amplifier. The fuse size does not determine the power output, the internal electronics determines the power output. ------------- Support the12volt.com
Posted By: Lifesavermobil
Date Posted: April 22, 2004 at 5:13 PM
Back to the basics. 1st, listen to the people, get a bigger alternator. Once you've done that, you need to get power to your amp with a wire. based on how much power your amp(s) draw(s), you need a certain size wire(s) to handle more than what the amp needs. To protect the wire(s) put a fuse as close to the battery (+) terminal as possible, 12 inches or less, to protect the wire. A fuse smaller than what the wire is/are rated is ok, a fuse larger defeats the purpose of having a fuse. If you distribute power to more than one amp or change wire gauge, put in more fuses for each segment rated at or below what they are rated. as for the fuses on the amp, you can go smaller, never bigger, just like the person did above. I've seen fried amps with solder melted, caps busted, boards charred and I seen installs where no fuses were used and the wire over heated, insulation melted, battery sweld, nearly every OEM fused blew and everything electronic in the vehicles fried too. spend the time and money to protect your equipment. The 12 volt site is a great place to find the information you're looking for.
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LifesaverMobil
Posted By: casedeez
Date Posted: April 22, 2004 at 5:21 PM
At this point I think I understand the dynamics of the electrical system. Now I need to know where I can get a good inexpensive alternator. Also I would like to know what size alternator I would need. I found out I have a 137 amp alternator which is original on the dakota SLT with the tow package.
Posted By: flatulatta
Date Posted: April 22, 2004 at 5:28 PM
id say somewhere around 200amp...or bigger if u can afford it... my friend was telling me that u can get urs rebuilt for around 55-100$$
Posted By: haemphyst
Date Posted: April 22, 2004 at 10:33 PM
You ain't gonna find an inexpensive good one... When referring to inexpensive in the heavy duty world, what you are really saying is "cheap". I do not recommend rebuilding or re-winding... what happens if the new one dies at some point in the future? Buy a new one, built specifically for the purpose, check with Alterstart in Texas. Good guys, I have dealt with them in the past, and good gear as well. My 165A for my Civic cost me 318.00, shipped next day, with lifetime warranty. I went with an actual new alternator instead of having my OEM re-wired, because now, if something happens, I have the original alternator to replace the dead one, until I get the heavy duty one back.
One more thing, and this question is for kickerstang... What ARE watts? Watts are POWER, which is voltage (14.4) times current (Amps) Yes, you ARE pulling power (watts) from your alternator, it is a power source. Watts are not specifically dedicated as an output rating on an amplifier. Watts is a measure of power, or work done, or energy converted. Have you ever wondered why nuclear power plants (alternators, or power sources) are rated in megawatts? It is to POWER all of the 120 watt (or 120 volts at 1 AMP current draw) lightbulbs (and other things) in our houses. You and I are pulling power in amps and watts from that power plant. It is the same thing in your car. Every load and power source is rated in watts. I apologize if I am coming off a little strong, here, but it did not sound like you completely understood the concept of power, and it's relationship to loads and energy conversion, and please take it as constructive, NOT destructive. ------------- It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."
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