I want to run a Solobaric S12L7 with a MTX1501D. I think that amp puts out around 1000w RMS. Then I have a little jensen amp for the components, I think thats about 200w RMS. Does that much power call for a diff alt or can I get by with a cap? Thanks

 

Andy...there are a few things that you want to do before you consider an alternator. First is the battery, cold cranking amps are important but reserve time is more important. I use Optima batterys in all of my vechicles. Mostly the red tops but some yellows. Next is the wire gauge. With that kind of power I recomend 0ga. I know it is overkill but not by much. You can add a cap (1 farad or larger will do the job) and you can upgrade the cables going from the battery to the alternator and the ground. The ground is very important in current flow. I do all that in every car I build for serious sound or competion and have only had to change the alternator in a handful of them. Later

 

If I use all that 0ga cable and buy an optima, it may just be cheaper to get a 200amp alt. I think I ve seen them for around 200 bucks. All I'm really concerned about is the ability to continuosly maintain the battery's charge while the car is running with the stereo on. I won't do any real competition so the motor should be running in most situations. What about that?

 

If you can afford a higher output alternator, buy it and keep your stock battery provided its in excellent condition. Just make sure your next batt is an Optima. That woudl be your best bet. Having the right wiring is given.

 

Well the installer I was talkin to advised 4ga. That may not be quite as efficient as 0ga, but I don't think it would be dangerous either. Yeah, I can afford a bigger alt, but do I need one is the question.

 

I would first try running the system with your stock alternator and a 1 farad cap. And see how it holds up the Jensen amp really isnt much of a concern because it will be driving your speakers and Jensen amps have very low current draw. As far as wiring I would recommend running 2 gauge wire and also upgrading your ground on your battery to 2 gauge wire. After that see how your system holds up at night with the lights, ac, and blinkers on and if it dims alot then consider an alternator. A capacitor doesnt allow you to always run bigger amps but rather it helps to regulate your system and keep it as constant of voltage as possible. If you get constant flashing of your lights it puts a huge strain on your battery and alternators. Also if you get an Optima battery get a Red top and not a yellow. Yellows are deep cycle batteries and are designed to be drained regularly, and from my experience it affects how well they start in the cold weather.

 

A quick note on capacitors. They are not a battery and do not regulate voltage in a system. A capacitor is a current regulating device. It supplies large amounts of current when needed by an amplifier. It charges and discharges instantly. A battery has problems when it is needed to deliver high amounts of current. As far as wiring it is easiest to look at this way. A piece of wire is like a garden hose. The larger the ID of the garden hose the more water will flow. So the larger the wire (actually the more strands to make the wire larger) the more current will flow. The more current available to the amplifier the less it has to work to try and get the current.

 

Kinda contradicting yourself there arent ya? Caps do help maintain a certain voltage in a car. But if your system is drawying more power than what the capacitor can keep up with then you should consider additional capacitors or a higher output alternator. Problem with adding too many caps is then not only is your charging system being dragged down by the stereo but its also trying to fill up those caps you have just drained.

 

How is EatRice contradicting himself? Voltage and current are 2 different things.
BadAndy, as far as your guage goes, don't listen to your installer. Go with 2 guage if you can find it. Otherwise just go with 0 but that would be an overkill but its still better than 4 guage.

 

A capacitor is is only truly working when an amplifier needs more current than is avaible or as some call a spike. When an amplifier plays a long low note it draws more current thuse it needs the current that is stored in the capacitor. A capacitor charges and discharges in nanoseconds. Once a cap is connected to a 12v source it is charged. If you arc a cap then it is discharged. It is not a battery. I have never seen a properly installed cap do harm to an electrical system. Also, every single amplifier available has capacitor inside to do the very same thing that is done when you install a large one on the power line.

 

Well I have I had one kid who purchased a 50 farad cap and hes killed his alternator in about a month cause it couldnt even keep up with the cap.

While all amplifiers do come with capacitors they are not of the same capacity of a external cap.

 

If the kid has killed his alternator then it was not the cap unless he installed incorrectly in which case the cap would most likely explode. I have installed and have seen installed hundreds of 1 farad or larger caps and have NEVER seen it cause damage to any electrical components. As for the amps no they do not have the same amount of capacitance is true. That is only die to the size of the cap and the size of the amp. I am sure if there was a way to get 1 farad in a smaller size then the amps would have that much capacitance in them.

 

I have a 1 farad super cap and probably need a higher alternator. With music full blast at night time, my battery gauge will jump from 13.x volts all the way to red. I'm going to try to upgrade my wiring to stock alternator first and see if that helps. What size wire should I run?

BTW, I'm running two SoundStream Van Gogh VGA320.4 (80x4rms) amps. Only 2 channels are bridged and the rest are in 4ohm load.

Thanks!

 

wow, an old thread, lol.

check your ground on the amps.

I believe the factory alternator puts out 140amps. I'm sure it's not at low rpms.

You are not drawing to much power. I would say maybe 500 watts rms or about 50 amps. Look at the fuse on the amp. That will give you an idea. 30amp = 300watts, 50 amp is 500 watts, etc. The fuse will give you an idea how much power the amp draws.

You can change the battery as another fix. Like I said, you are not drawing allot of power. It could be a sign of an alternator going bad, or a bad ground.

If you do the battery. QUOTE ME here because I know that some are using the redtop optimum batteries. Do not use them. Use the yellow top, the red ones are not supported for stereo equipment in the car. This is from optimum directly. The battteries won't hold up or could get damaged. The yellow top are designed to have a slow draw and remain constant level outputs no matter how much strain on the system. The red is designed for emergency vehciles that need extra batteries. Like I said before, they are not support and will not be warrantied by optimum if you are using them in a high powered car audio system.

 

I'm running 2-8ga power wires (pulls more current than 1-4ga plus had 1-8ga already ran). Running a 4ga ground that's got a "T" connector with 2-8ga off of it to the amps.

I'm running a decent amoutn of power. 640w RMS powe ror 1280 peak. The peak is where it's hurting.

I have a red cap now. always heard/yellows are deep-cycle and used for when the car isn't running. anyways I got a really good deal on the new battery and my AcDelco was done with anyways. Everything was fine when I was running only a 65x4 rms amp. when i installed the new amps, I can tell. lights dim really bad too.

I'm going to upgrade the wiring first and see if that helps. do you think 4ga from chassis to battery and another from chassic to block? 4ga power from battery to alterator as well. Think that's good enough?

thanks for the help!

 

haven't read a lot, but:

capacitors are bandaids. high-output alternators are the solution.

optima battery will do nothing more than a good ole autozone battery. don't waste your money. everyone goes on and on and on about the yellow/red top batteries, and truth be told, they will perform nearly the same next to each other. the "optima batteries are the best batteries you can own," is the second biggest ls1 owner brainwash up next to the, "zaino is the best thing to put on your car" one.

the way to get the most out of your battery is to upgrade the stock ground connection to 4 gauge as well as the wiring that runs from the battery to the 12v accessories on the other side of the engine battery. if you want a good battery to run your stereo on when your car is off for a long time, sure, buy the optima. i doubt you'll need to do this.

as far as "will you need a high-output alternator," it depends on how much lights-dimming you can handle. i have 2 10"s at 700 watts RMS and my lights dim to a noticeable effect. if you can handle it, then so can your alternator

and 4 gauge wire split into 2 separate 8 gauge wires will be good up to about 1200 watts RMS, then you need to upgrade. just make sure to keep the 8 gauge power wires and ground wires as short as possible.

 

peak is usually translated into "bullshit." so you have an RMS power and a bullshit power, and usually the bullshit power number is bullshit because it's just a selling number. sometimes it's relatively true, but not usually. base your power on the RMS number, not the other numbers.

 

True that, but actually (this is the only case I've seen) my amps are model VGA320.4 and that's actually the RMS power. I said peak just because...

 

Any suggestion on how many feet I'll need? Maybe 3ft of ground and 3ft of power?

Here's a little video I did yesterday to show the how much the voltage drops...
Fixing to order some 4ga wire. What do you think?
http://infinitereality.250free.com/V...oltageDrop.WMV

 

that file is too big. it can't be over 250k.

if you are staying above or around 13 (according to the voltometer, although it's pretty inaccurate), you should be fine.