Alternator Question

Here is what i need:

-Alternator-
-Minimum 120a
-Near 200a would be optimal
-Less than 300 would be nice
-Externaly Regulated (id like to run it at 14.4v) or
-Internaly Regulated to 13.5v
-It has to be a Hot altinator
-Id like it to be bolt fo' bolt on the truck in the siggy (2000' Mazda B3000/ Ford Ranger 3.0l)
-If it isnt bolt for bolt it needs to fit with only some bracket fabrication and a belt replacement. I will find out what type of belt i have and post it later in an Edit. its 35 degrees outside right now.
-If it isnt bolt for bolt do i need to insulate the bracket or make a bracket that isa good conductor (is it single pole or bi pole)
-Under 300 peaz...

Incase you are wondering why i need 120minimum but 200a optimal. I'm evenually going to be throwing about a 2000w stereo system (my siggy soon to be modified for what i want). and eventually near 3000w. Yes, it will be loud. I'd also like some advice on bateries. i am thinking Optima Deep Cycle Marine. Oh and incase you are wondering why i just dont ask the audio guys. well most have no idea where to find altinators. ie, myself, Soundillusions.net, etc...

check if any RV's use a similar unit. You may find a stock unit from one that will fit right in there. Brackets are easy to make if not. Good Luck

You're on the right track with amperage, but don't use a deep cycle of any kind. Just stick with a good regular battery unless its a show-only vehicle.

Consistent cranking and the constant full-charge state will not be good for the battery.

Deep cycle batteries are desined like a bucket. Dump a bunch of water out at once, then refill it quickly. Regular batteries are designed like a bucket with a tiny hole and the alternator trickles juice in to keep it full. Although it doesn't seem like much there is a huge difference. Deep cycle bats are designed to cycle deeply, but when the truck is running, they won't cycle AT ALL.

As far as sourcing the alternator, find out every vehicle that used this engine or family of engines. Then go to the parts store and look up the alternators available on all of these vehicles and chances are you'll be able to find at least one or two steps up in amperage. If that's not enough, you could run two alts, or break out the welder and start fabricating. Summit sells a 140 and a 200 for pretty cheap. They are designed on the 12SI body GM alternator. Find a serpentine pulley for it and fab up some brackets. I did that once on a Dodge Caravan and it was pretty simple.

are you sure about the battery. Battery reserve is what really matters when you are talking stereo's and that is where deep cycles shine over regular batteries. so what battery do you suggest? Optima Red? (im pretty sure Red is regular yellow is deep and blue is marine deep)

True, reserve capacity has some to do with stereo prowess, but you don't have to worry about it. Let's say for instance you are running 3000w RMS. At its absolute peak, you're probably pushing 4000w during an extreme bass hit at the highest non-distorting voltage you can achieve. Although it might be rated for a peak wattage total of 6000w, unless you've truly perfected your system with every speaker with a sensitivity of well over 100 dB and enough Xmax to draw 6000w, it will never use that much. At 4000w that's about 275 amps for a brief split second. On the average your system will probably draw more like 80 amps. With the volume at zero, it probably wont draw more than about 15 amps. Your starter draws anywhere from 200-300 amps for much longer times than your bass hits last. And think about how long you could hold the starter engaged before you drain the battery.

So, if you look at the system as a whole, with the stereo cranked and bass vibrating the neighborhood, you'll be basically cycling the top 1-2% of the reserve available from the battery every few seconds. Hardly deep cycle. This type of amperage draw will be handled by your alternator. a 200 amp alt will easily be more than adequate to replace the split-second 275-amp draw. A bass hit with that system would look the same to the battery as briefly bumping the starter. A deep cycle battery is not required for that type of draw.

I strongly suggest at least two, one-farad caps. That will remove the amperage spikes from the alternator and battery and buffer the whole thing. Then your caps will supply the bursts of amperage, not the alternator and battery. They are designed much like a deep cycle battery that is designed for extreme discharge and charge in very short periods.

If you crave more reserve capacity, run two batteries. That will double your reserve without asking a deep cycle to perform like an automotive battery.

Although I've never run more than 750w, I just use a good Exide store-brand battery and I've never had problems. My Impala SS in the photo below has its stock 140-amp alt, 750w of RMS power (although recently I removed the sub and about 400w with it) but believe it or not, I just recently replaced the FACTORY ORIGINAL Delco battery. 80k miles and 8 years of punishment from 750w of stereo. I replaced it because it leaked, not because it died :) That is rare and I'm sure I just got lucky.

Since you are planning as much as 3000w, I would shoot for maybe the Optima cranking battery (whatever color it is). They have darn near perfected battery technology and it is a darn good battery from what I understand. I've yet to make the jump to Optima because I've had great luck with good old Exides. Anyway, if you need extra juice you could run two of those.

Good advice from curtis.
As for an alternator, 4x4/off road specialty stores and websites offer custom modified alternators which have the specs you are looking for.
Many people happily place 1000 watts of off-road auxilary lighting, hence the need for a serious alternator.

koolness, i understand where you are coming from curtis. will do. im about setteled on a mean green. form what i hear 170a@2500RPM and 100-120@idle. im starting off with a BX1800 or somehting like it which really only does about 1400wRMS. but curtis, i think you need to step into the world of XBL^2 and see what real excursion is....

:D :D I hear you on the XBLs. I met a guy with a late model caprice with two subs on the back deck. I forget which ones they were but they were known for their Xmax. His problem was at the back of the deck where the glass was close, his surrounds could contact the glass on heavy hits. Now THAT's some excursion.

I usually deal with SQ instead of SPL. I'm a jazz and classic rock kinda guy. Two sealed 10's are my pick. I used to have an SPL car; a beretta. I had two MTX 18s in the trunk driven by about 2000w of Altec Lansing amp. They were ported encolsures and had to be assembled in the trunk since it was so huge. Like 3.5 cu ft per sub. Each one had two 4" ports at about 11" long. It was just painful :) I could also open the trunk with the subs. I had to be careful driving down the road that I didn't pop the trunk open :D

Ah, yes... 1990. I could blast Bel Biv Devoe all day and it was cool.