How to achieve 14.7 voltage?

[jrwalte 10+ year member]

For under 1000 RMS you do not need an HO alt. Do the big three if your stock wire isn't at least 4g and get a battery for the rear. Yellowtop would work but powermaster/kinetik are better.

 

[helotaxi 5,000+ posts]

The need for a HO alt is largely misunderstood and thus greatly exaggerated.

 

[TSGP]

people don't understand...upgradding your alt is basically like adding 2 batteries.

a decent single battery is good for 100 amps of draw over long periods of time.

But keep in mind with factory alts when you start stacking batteries on it its eventually going to fail...and ho alts are designed to run under loads like that

 

[Saint211 10+ year member]

^^ agreed. The way I understand it is the batteries act as a cushion/reserve/whatever your word is, in a sense. Problem is once you reach the point of drawing off them your alternator is under strain. While the power is on tap during the time when it is needed, and in parts of the song where there isnt extreme bass, your alt should charge your batteries. Thats where the whole "music is dynamic" thing comes in. Any stock alt under these circumstances though is taking more strain than it was really designed for and its life wil be shorter than normal.

While the part about a h/o alt being like adding two batteries is correct, its still better to have a good solid h/o alt because they can go further before straining, are built to handle more strain, and have more capacity to charge the batteries.

Of course thats just my view on it, I could be totally mistaken.

 

[TurdFergueson2 5,000+ posts]

anybody know a website i can go to lookup the amperage of my jeep?
Also, i know this question is asked alot, but would buying a yellowtop for the back keep up well with my daily demands? (less than 1000WRMS)

EDIT: I have a redtop up front already

I believe yours might be a 130 like my 300M had. You could go to autozone.com and price one. I wasn't seeing 14s till I swapped it out with a 250 amp Mechman. I had a red top up front as well.

 

[photocrazy8 10+ year member]

The need for a HO alt is largely misunderstood and thus greatly exaggerated.

this man is my hero when it comes to car electrical //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[helotaxi 5,000+ posts]

^^ agreed. The way I understand it is the batteries act as a cushion/reserve/whatever your word is, in a sense. Problem is once you reach the point of drawing off them your alternator is under strain. While the power is on tap during the time when it is needed, and in parts of the song where there isnt extreme bass, your alt should charge your batteries. Thats where the whole "music is dynamic" thing comes in. Any stock alt under these circumstances though is taking more strain than it was really designed for and its life wil be shorter than normal.

This post almost perfectly exemplifies the common misconception about the relationship between the batteries and the alt. You don't have to even approach the capacity of the alt to begin to draw from the batteries or get the lights to dim. All you need to do is have a rapid spike in the current demand. The alternator only produces the amount of current that is being demanded at any given time. It takes time for the regulator to detect a voltage drop from an increase in current demand and adjust to compensate. During this adjustment period, the battery or batteries are taking up the slack. More batteries allow for a bigger spike without a huge drop in voltage. Depending on the nature and duration of the current the alt may not contribute to it at all. For example the spike from a musical transient may well be over before the alternator reacts. As such there's no strain on the alt at all and it must only replace the charge lost from the battery. The amount that the voltage drops during the transient depends on how much reserve current you have in the batteries. Regardless of the size of the alt, this same thing will occur. All you need from the alt is to be able to cover the average current draw of the system. The batteries allow the peaks to be averaged out so the peak draw of the amp is only important in determining the amount of reserve you need in the battery bank. Adding more batteries adds no more real strain on the alt until you're talking about a trunk full, or you've got such a high average draw that the batteries are being discharged continuously. With music, the latter is nearly impossible unless you're listening to stuff that has a very small crest factor on the bass (I'd hardly call that music).

While the part about a h/o alt being like adding two batteries is correct, its still better to have a good solid h/o alt because they can go further before straining, are built to handle more strain, and have more capacity to charge the batteries.

Adding a HO alt is rarely needed. They add no capacity for transient demand. They also usually provide less current at low RPMs which could allow them to be overwhelmed by the system and the batteries to be discharged.

The use for a HO alt is when you're adding devices that have a continuous high drain such as compressors for an air ride setup or a winch or a ton of lighting.

 

[MikeyB 5,000+ posts]

^ Word.

 

[Saint211 10+ year member]

I know alternators only produce current on demand and obviously music has spikes in demand. But in theory explain this to me....If I do a 50 hz burp, with 2000 watts rms on a 130 amp alternator wouldn't it be demanding ~200 amps of current from the electrical system. Obviously with batteries you can make that demand, but wouldn't the alternator be attempting to provide said demand as per your words? Now how about a 50 hz burp with 4000 watts rms.... demanding ~400 amps?

Honestly, I dont know everything... thats why I post here, so I can learn more. But I dont see where an alternator thats constantly having to charge batteries and get surges in current demand(which you said the alternator still tries to compensate for) isn't going to be under more strain than an alternator that only needs to charge one battery and provide headlights for a grocery-getter.

Im not hyping up high output alternators, but I would rather have a nice built from the ground up high output alternator than a stock one. When you get into rewound alternators is when you lose the low RPM current supply. A good h/o will still do better output at idle than a stock. I am a believer in your electrical system only being as strong as its weakest link.

 

[helotaxi 5,000+ posts]

Burping and daily are two totally different things. I'm talking daily. If you're planning on competing in an SPL class that allows you to run the car during burps and you plan to power the system off the alt (which I would as much as possible) you're going ot want several big alts and you'll still need a bank of batteries.

As far as for daily use, the alt will try to compensate for a for a transient spike but by the time the amp starts upping the current, the spike has passed and the little bit of charge taken from the battery only needs to be replaced. A battery or batteries only needing a little bit of charge doesn't draw a lot of amperage from the alt, only a couple amps that quickly tapers off. You also have to consider that the transient isn't going to pull full power out of the amp and thus it isn't going to go to max draw. The realistic average draw for a normal system in the 1kw-ish range is probably going to be less than 20A. It depends somewhat on the crest factor of the source and the volume habits of the listener but my point is that most people grossly overestimate the amount of current that their daily system needs to keep the batteries charge and not cook the alt.

 

[Jameseypoo 5,000+ posts]

Have you tried marbles?

 

[BlurredVision 10+ year member]

So I want to put about 3000 watts total in my Explorer. So a few deep cycle batteries are the key to keeping the power steady and voltage up? And you just need the ho alt to keep the batteries strong to not to keep up the voltage and draw?

 

[Andrizzle 10+ year member]

Iraggi, 5 Kinetiks, lots of 0/1

 

[Pioneer~Saturn 5,000+ posts]

x10000000000000000000

x2...as long as it's any kind of respectable voltage, worry about having backup for that voltage //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[Pioneer~Saturn 5,000+ posts]

Iraggi, 5 Kinetiks, lots of 0/1

You adjusted that just for the pic, didnt you? //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif...jk //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif