i was talking to a guy at a custom audio shop yesterday, and i was talking to him about my system...well obviously i only have room for one battery (i have room for more, but i refuse to run more than 1 battery becuase weight is already getting too much in the rear....)

anyways, im gonna run the biggest batt i can find, most likely a kinetik HC2400, or a Powermaster 3100.

now, i wanted to upgrade the alt, which is a PITA to get to, as most of you know, so this guy was telling me to get a 300a alt , and i can mount it (i have the room) in the engine bay located in the pic below (i would have to cut some of the plastic away, who cares)

problem is, getting a pulley from the stock alt, to the location of the 2nd alt.

any ideas on how i can make this work?

 

No idea HOW to do it... but I'm curious: what kind of parasitic effect is that going to have on performance with such a small engine?

 

lol sorry, its not for that, its for audio, to keep my voltage maintained

 

I figured as much, but I was more asking about the physical turning of two alternators instead of one. I'm guessing that has to put a little more strain on the engine, right?

I was just curious as to how much it would strain the engine and if it would have any negative effects on the stability and performance.

 

Hmmmm, ... not sure why wieght would be an issue for you at this point. But I do think that a second battery is a better way to go rather then a second alt. Not sure anyway how you could hook up two alts to one battery without it just shutting down the the smaller alt. I think this would be a ship load of problems, right down to a freeked out ECU.
If weight really is an issue then look into ODYSSEY batteries. Very light and very powerful for thier size.

Also, two alts would rob you oy a ton of power I would think.

 

why not run four Braille (or similar) batteries in a series/parallel config to give the same load but more run-time? dual alternators on a car not meant for it is not for the faint of heart. Working out the belts, the isolators, etc....other ways to skin this cat.

the best way to deal with the alternator is to buy a spare OEM replacement one and have it rewound for a high output version. You might want to call Rockford Fosgate or JL, as they have done show systems in a MINI before and have had to cross this bridge before. Most use 120v supplies onboard with a 12v output, so that might not be the help I would think it could be.

 

im refering to weight being a problem just becuase i dont want too much and sagging down the rear, or possibly messing up my transmission in the long run (can that happen?)

also, adding more batteries on a stock alternator wont do much. when the amps draw current, and drain the batts, theres still only 1 weak stock alternator to charge up, not 1, but multiple batteries...that much more stress on the alt, and itll take that much longer.

so adding more batts with no way to keep them charged, does nothing really.

i actually might just keep the stock battery on the stock alt for the car (as the starter battery) and add a dry cell and a HO alt (IF i can find out how to get one installed) for the system, so technically itll be 2 seperate circuits.

 

cutting that plastice leads right to the wheel well and from having my mini apart there is not allot of room in there.

 

hmm 48V in a 12V circuit. better wire that in parralel.

I would say to just swap your existing alternator with one that creates more amps. With that of course, you will be in need of heavier wires, not to melt any you are already using.
Before you do anything, how many amps will you need to blow your brains out with your desired setup. Figure that out before spending money on second alternators/batteries, etc. Remember function > fashion.

 

I think he's trying to do more then blow his brains out. Even a small 350w amp with a 12in sub can make my hair dance and my ears bleed. His setup borders on blowing brains out withing a 1/2 mile radius.

 

2nd to none has it right, you need to find out what your load is first, then size a new alt accordingly. And he's right, upgrade the size of the hot lead too.......a 2nd alt won't help as much as one alt sized right for the load.

However, if you decide it has to be two, I don't think it will cause problems if you buy a "one wire" type and hook it dierctly to the main lead to the battery.

2 smaller lighter batteries with greater storage ability is also a better idea.

 

Ill have 3 amps total.

1 amp is 750w rms x 2 @ 1 ohm (for 16 mids)

The next amp is roughly 250w rms x 2 @ 2 ohm, for 16 tweets.

The one that will be the biggest problem is the sub amp. 3000w rms @ 1 ohm, and that's under rated. They do more like 3500-3600w rms.

 

5.5kw on the output side. Probably more on the input side to keep up with power loss within the amp itself (amps arent 100% efficient [in fact I have no idea how well they work]) but if you look at it like a computer PSU which usually run close to 80% efficient then you are looking at close to...

6600 12vDC watts for the sound system alone.

Then use W=VA you get...

550 amps (at 12volts) just for sound. Then add on things on top of that you could be looking at over 600amps total. That is one massive alternator.

What class of amplifier are you using? Obviously that is going to play a major role on how much amperage you are going to need.

 

After riding in the car, Cap'n Sparrow says:

 

The 3000w is class D, the other 2 are class A/B.

 

Could put a gasoline powered generator in the boot and route the exhaust
out back. Might be noisy with the sound system off, but it looks like you
could drown it out.

 

sub amp: http://www.mtx.com/caraudio/products...under92001.cfm

mids amp: http://www.mtx.com/caraudio/products...under91002.cfm

tweets amp: http://www.mtx.com/caraudio/products...hunder8502.cfm

 

The human eardrum instantly perforates at 160db.

You know... just an FYI.

 

ive sat in vehicals that do 160 dB

 

What's that? WHAT?

Could you speak in ALL CAPS so I can hear you?

 

ahaha

 

Not even going to ask how much that costs...

Do you plan to use the whole system all the time or is this for competition? That will play a role in how you solve this problem.

 

Just having some fun,
I'll stop now.

 

its a daily driver

 

Oh... Now it gets fun then.

Solar panels maybe? (joke btw) I am really out of ideas. Putting on a second alternator big enough to power all of this is going to drain a lot of power from the engine.

Is this a situation where money is no object or is it something else?