multi altenator wiring question.

[triple7wva]

heres a question for you guys who have done multi alt's on your veihicles. im finding that im realy taxing my stock charging system on my 4.3ltr blazer running my 93t,3pill and 10pill. ive got a 320amp leece that i was planning on using but is that too much? or would i be better off going with 2 smaller leece's?

i need to be able to run my 32pill comp box on this but ill mostly be running a 6 or 10pill. how do i do the wiring? what about external rectified? i know im gonna need voltage regulators. what brand do you recomend? thanks.jas

[Sheriff Bart]

The alternators out put goes to the positive post of the battery or batteries. If you have an alternator that is not internally regulated, you'll need to buy a regulator you can dial from inside your car. I would run 0/ga. welding cable from the alt. to the pos. side of the battery and likewise ground the negative side of the battery to the frame of the auto using the same ga. welding cable. Only thing you need to do next is provide a way to turn the field on and off because when you don't need to have the leece on you don't need to lose the rpm's. The size leece you have is adequate, I would use it and only if I found it now powerful enough to handle all my needs would I consider lacing on another (or third) alt.
hmmm, I see you have a 32 pill also...okay I would have 3 (total) alts. One the stock alt. that keeps the mobile running. The 320 leece for the 10 pill and at times the 32 pill and a smaller leece around 200 amps for the radio and 3 pill.
Remember this though, multiple amps mean multiple battery systems. As an example, you use two 1000cca batteries for your 320 leece, you need two 1000cca batteries for the 200 leece. You cannot dump both leeces into the same battery (batteries).
Wiring is simple, an on off switch and regulator. If you use two leeces you need two on off switches and two regulators.
If you have one leece and two batts. you will wire one side of the switch to the pos. post of the battery that is linked to the leece. The other side of the switch goes to the regulator and the regulator is wired to the field terminal on the leece. All grounds are common.

[North Texas Mudduck]

keep in mind 320 leece gets real hot
so after few minutes of keydown time your 320 leece is going to be in 250 to 270 amp range

so if you have say 2 smaller leeces in the 250 range this will have you at the 500 amp cold start then drop back to the 400 to 400 amp range

me personally and i dont know to much about this stuff
but with a 32pill i would have 4 alternators dedicated just to the main amp
now thats just me
im sorta overkill type person maybe thats why i get my name called

and the 4.3 liter is going to be taking a load and you be going downhill 80 to 100 to get everything you can

[Sheriff Bart]

texas mudduck, you gave triple 7 an ideal competition setup but I didn't think he wanted anything but to bump it down in skipland. Since he already has the 320 leece I gave him a blueprint where he could utilize it, get another smaller alt. for his driver and radio and have an efficient system capable of 2Kw to 2.2Kw with the 10 pill 3 pill driver setup and between 6 to 7 Kw with his mule inline. (not hitting the 32 pill too hard)
triple 7, what northtexasmudduck says is true for an all out competition setup. Now I will say your 4.3 will turn that 320 and another alt. in the 200 or less amp range along with the stock alternator without any problems. That 4.3 has the same slugs as a 350, just minus 2 cylinders. I had a 4 cyl. volvo that had no problem with 3 alts. and only needed to take my rpm up to 2500 to throw 2.5 Kw with a 3 pill hitting a 12 pill.

73's

[triple7wva]

well i got my new 4.3 put in today. got my heads,intake,carb and msd box put it. built a mount that will hold 2 more if i need them. the msd box rasied my redline and what not. i hit the limiter at about 7800rpms acording to my monster tach. if i find i need more power from the motor ive got a 355 and turbo 400 trans in the garage that will slide right in. i sold my damn suburban a few weeks ago. couldnt aford to drive that sled around with the 396 in it. tore my **Censored** up in gas.

this is just gonna be my skipshootin mobile. i may add 2 smaller leeces and go to the watergate city break and key in the 8pill or 10 pill class but im not even gonna fool with the 32pill for that. i may get a wild hair and sell the 32pill soon to get a new radio..who knows..lol thanks for the advice guys, i printed this page and got it in my shop for reference....jas.

[Big B]

A 320 amp alternator is NOWHERE NEAR large enough to power a 32 pill amplifier. Adding batteries in a failed attempt to apply a band-aid fix to the problem won't do the trick either. More batteries just increase the load on a charging system. I've posted it before, but I'll say it again. Allow 20 amps for each 2SC2879 when figuring alternator output. This will avoid drawing more current from it than the rated output, and give the alternator a little headroom. As the alternator rectifier pack's temperature rises, the output DROPS. With some poorly designed (cheaply made) alternators, this drop can be pretty substantial. The best aftermarket alternator manufacturers/remanufacturers/suppliers are confident enough in their equipment to rate products at specific operating temperatures. Take this to the bank.............

[dud muck]

A 320 amp alternator is NOWHERE NEAR large enough to power a 32 pill amplifier.

Big B hit the nail on the head.
Probably should be sufficient to have one leece for 16 pills and another for the other 16.

At 32 pills you've reached the point of absurdity where you need to move to AC operation.
Most of the power loss is from running at such a low voltage.

Just thinking out loud:
I was reading up on alternators, and it seems that if you remove the rectifier and regulator, you can get upwards of 30,000 watts out of an alternator (120vac @ x,000rpm). But rubber belts wont do, chains are required. Anybody do chain driven setup? The limit becomes stress on the alternator shaft bearings. 30kw is about 40 horsepower. But at 14vdc out at 320amps, only 4 to 5kw can be had.

Most alternators it seems run at 2x the engine speed. might be more effective to run at 3x engine speed?

[Big B]

Reputable suppliers will provide a customer with their recommended alternator operating (RPM) range, and can provide a selection of pulley diameters to help keep the alternator in this range.