You must be running a really innefficient system and/or don't have much experiance with car audio systems. Unless you are running like 10k watts or some crazy amount (like major show car) a second alternator is far, far from neccesary. With the proper amp(s) subs caps and wiring, you should not even need an upgraded alternator let alone more than one battery, assuming the proper battery is used in the first place! Even when more power is used, a secondary battery would be much better than a second alternator or even an upgraded alt.

 

Man don't you love when someone gives advise (wants to sound smart) without even knowing whats going on? I suggest everyone read all the replys to the threads before spouting off thier "words of wisdom" to others...Might save you the taste of Feet...

 

FYI im using 3 batteries... all currently mounted in the car

 

he does bring up a good point why not use some caps as well. they are quite necessary for that kind of setup

 

so at the end of the day u got a 16 sec cobalt with 200hp..danm,lol

 

compare a few 1f caps that have the capacity to send a few amps to the amp for less then a second before they are drained to a second alt and 2 16v kinetik batteries.... when my setup is complete can basiclly run a sine wave for a while without loosing power.... i said basiclly because the max output on the alt is 245a so at max output and at 16v (although to charge the batts the alt will be at ~17 or 18v) it produces 3920w of raw power, the amp is rated at 3688w at 14.4v so at 16v+ its should bump it up a bit (for demo purposes we can assume its 3920w) but since the alt wont be running at max amprage at all times the batteries with a capacity of 62ah each will kick in for the exra power.... So in real world terms at ~3600 rpm i can fun the amp at full tilt for an hour with little to no voltage drop. Now since the subs cant handle that much for that long i should never have any problems with power loss. Oh and to all you technical peeps that are going to say i never calculated resistance and efficency of the amp, Im going to be using 2/0 wire (5929 stands of copper) for EVERYTHING in the secondary charging system along with 8g speaker wire for the subs (quad coil with each coil getting its own 2 terminals) so while there going to be some loss in terms of resistance there isnt going to be much and in terms of amp efficency the weak link is going to be subs here so even thou i wont get every single watt going to them they couldnt handle it anyway so a few watts lost is fine

actually more like a 16 sec cobalt with 240hp. but i really dont see how people can spend the cash they do on going fast and talk **** to everyone else that doesnt do the same. Its a cobalt and fwd so if i was looking to really go fast i would have bought a different car or done a conversion to rwd or awd or somethin... plus pretty much everything im doing is unique and custom which imo is going to get more attention then someone with all the preformance mods that a ton of members on the site have (not saying they are bad but custom>common) and i can guarantee i will get more trophies for my 16 sec cobalt then your 13 sec cobalt

 

i actually highly doubt it. i know alot of 13 sec cobalts that have a combo of performance and looks that have won 10 plus trophies in just one season. just out of curiousity are you only having subs or are you amping your interiors as well

 

yes everything is being amped and changed out. im not even going to be using stock speaker locations

 

You also know that the vast majority of the power output of alternators is in the mid to upper rpms? so... unless you plan on driving your cobalt around the competition, you might want a more efficient setup

 

yes i am aware of that but i was giving an example of optimal run time. for competition all i need is ~3 seconds of power for spl and 30 seconds for streetbeat (amp only uses ~half the power)

 

Well at least you know then that's good Question though, why do you think you need as much output from your alts as you are getting from your amps?

 

on my jimmy i had a rewound alt...it used to be a paramedic supervisor truck, had all the lights and sirens taken out before i bought it though ...and stock was 140 amps and this one was pushing 200 or so and what they[a local shop] did was get a core one rebuilt it and "rewound" it...I wonder if you could have done the same here, just found a wrecked balt, pulled the alt and took it to a shop to "rewind" it

 

i dont need it... and its pretty close to overkill for what i have planned but thats the goal. I should never run out of power especially for daily driving.... plus it leads the way to get more amp power if i ever decide to do so

 

Great job Emp.

Nice to see SOMEONE knows what they're doing. Phuk the haters. They don't even know.

What RPM's does that alt. charge at? I suppose with an external regulator it will help it run cooler and should put out at a lower RPM.

 

could of but that would be too much effort for not enough gain. Stock at would have ran me ~ $50 and say 150 to get the rewind (no idea how much it would have been) to what 200a? i wanted more so dual alt it is

 

me, i'd always rather go with multiple stock sized alternators, rather than a single high amp, or even dual high amp.

reason being, typically the higher the amperage, the higher the rpm has to be in order to get that full amperage. Now, you may think you've upgraded by just putting in a 200a alternator, but in all reality, your going to be getting less power at the idle than the stock alternator.

So, thats why I'd go with 2 stock sized, or just above stock. no sense in having the power output you want, if you gotta rev to 2,500-3,000 rpm's for it.

 

thats what the batteries are for... capacity for when the alt isnt producing all the power. But i agree with you somewhat. Hence keeping the stock alt and just adding the big one

 

It'll be nice once 42 volt systems are the norm. Won't have to deal with this anymore.

 

EmperorJJ1, your badass man.

yes the batteries is a way, but i assume that like you, we don't wanna litter things with extra batteries. :-P

 

Read his premium member thing: "Car Audio Guru". Now put one and two together.......let it marinate in your head a moment......car audio.....two alternators.....got anything yet? It's b/c its neccesary to either run dual alternators or a beefy alternator from like MSD when you start getting serious about running big audio setups. Not being rude, im just cocky like that.

 

lol my 3kw amp doesnt make power out of nowhere... gotta have something to feed that monster

 

We will see what my Stetsom 7kd amp does with no extra alternator lol. It sure wouldn't hurt to have one with 7000+ watts but the amp will only draw up to 650amps. Really awesome amp. I was going to run two of them but dont think im going to compete like i use to due to time so i think i will be fine.

 

I really want to see one of those in person (really the insides).... but i dont think ill be getting one anytime soon. But who knows ill see how much the fosgate really likes high voltages and go from there

 

There a good size i have seen a few. I would like to see the inside also thats one think i hadnt seen yet. Maybe i will take one apart lol. Those RF are nice too very powerful. I had 16 MTX 1501 in my truck that was charged up to 22volts they really liked the high voltage. It increased the power like crazy. It was measured at 20000 watts with 8. I had 8 on each sub :-)

 

Are you guys saying that giving your amp more then 14.4 volts is not bad for it, but infact, allows it to put out more power? (I know how the equations work, just didn't think going overboard was smart) I always thought operating range was something like 11.5-16.5 and any more or less would do damage?