alternator size

[idi traveler]

I would say that is correct, the path of least resistance should determine which one is dominate.





Yeah, so long as it is a parallel wiring. Parallel will double the current draw from the regulator - but the old mechanical ones are pretty robust. Wiring in series will lower the voltage of the signal to the second alt, which will only activate the first alternator in series and leave the second one off.

Now that I can see the schematic, I'm confident that sharing the F and S signal lines would work really well. I'm tempted to remove the regulator from my 3g and see if an external unit can drive it. Dual 3g's would seem like a lot of fun

wiring in series will lower the voltage to both alt., and neither will work. all you need to test the out put of an externally regulated alt is put 12V across F and S a good alt will produce a good output. If you are able to get a heavy enough reg. then parallel driving of the the 2 alts. might work. I don't think that there will be a dominant alt. though. The atl's will be unaware of each other, all they will see is the control voltage from the reg.

What I can foresee is if one alt has a diode, field or armature short you could back feed from one alt to the other and possibly make smoke somewhere other than the exhaust pipe.

another option would be to charge 2 batt's with one alt and 2 batt's with the other. Use deep cycle batt's for you stereo and you reg batt's for starting the truck. Seperate systems, no smoke, no get stranded.

 

[LCAM-01XA]

What I can foresee is if one alt has a diode, field or armature short you could back feed from one alt to the other and possibly make smoke somewhere other than the exhaust pipe.

They do make battery isolators which are nothing but two huge diode-like things inside them, so something like that may work for this application as well - both alternators feed into it, but since their common point is on the other side of the isolator there will be no current backfeeding into any of them from neither the other alt nor the batteries.

 

[runaway!]

What I can foresee is if one alt has a diode, field or armature short you could back feed from one alt to the other and possibly make smoke somewhere other than the exhaust pipe.

If the alt shorts out, you won't need a second alt to make smoke - the batts will try to drive it like a motor. I just put a 100+ amp ANL fuse in line with the alt. If anything fails the fuse will blow before the fireworks begin.

 

[CDX825]

Wiring alternators in parallel can be done and they do make voltage regulators for such a setup.

The alternators would have to be the same though otherwise one would be doing all the work.

In my opinion this is not worth it unless your running multiple leece nevilles. Two 1Gs output could be made by a single alternator.

A 3G or high amperage 3G would be the way to go and if thats not enough look into a leece neville.

There is a point though witch you will just start slipping a single v belt setup.

Here is an interesting video! These guys put the car stereo crowd to shame with their alternator setups!
http://www.youtube.com/watch?v=RRDA64OegJY&feature=channel

 

[idi traveler]

Just one of these might be just what you need! http://www.motorcityreman.com/leoe48a01.html

check this link out and use the drop down menu for their 250 amp 3G!!!!!!! http://www.motorcityreman.com/high-amp-alternators-ford-cars---trucks-f-series-truck.html

 

[sootman73]

Wiring alternators in parallel can be done and they do make voltage regulators for such a setup.

yea you can order dual alternators on the new superduties.....

 

[runaway!]

I'll have to take the VR off a small case 3g, see if it is just a field and stator connection to the actual alt. If so, one could use an external VR, any case size 3g, and fab up a bracket. I have the AC delete pulley on my PS pump, could drive the other alt off that...

 

[runaway!]

yea you can order dual alternators on the new superduties.....

I'd be surprised if that was an external VR though. Aren't 6g alts ECM controlled?

 

[timothyr1014]

in the process of rewiring one of mine, along with doing a serp belt conversion...because i have always had good luck with them (and they're cheap) boneyard delco 300 amp 1wire...

 

[LCAM-01XA]

300 amps? What GM vehicles did those come in?

 

[timothyr1014]

was standard equipment on all early 90's cadis with the heated windshield option; find them all the time for $25 at mmy local pick and pull.

 

[LCAM-01XA]

Is that the big RWD Fleetwood Cadillacs, or the smaller FWD ones?

 

[timothyr1014]

smaller fwd''s, the most common are 90-93's all body styles except the rwd ones. easiest way to tell if they have the option package is to look for the "de-ice" switch...on the seville and eldorado its on the seat-heater lumbar switch on the center console between the seats, on the devilles and fleetwoods its on the dash just to the right of the information center below the "window lock" switch.

 

[LCAM-01XA]

Good to know, thanks for the info - guess that's one more thing in my list then...

 

[MIDNIGHT RIDER]

these rated power outputs are usually at 2000 rpm.

Exactly.

Just like electrical powered products and lawn-mowers, advertised capacity is usually only available just before disentegration and the actual usable capacity is often quite a bit less.

Also, a lot of pulley math goes into acheiving optimum alternator performance.

It is also important to know whether a specific RPM figure is ENGINE RPM or ALTERNATOR RPM; with most pulley set-ups, alternator RPM will be about double engine RPM.

if you are idling at 650 for extended periods of time then the alternator will prob not keep up with how much power you need.

EVERY truck engine should be equipped with a locking throttle-cable and any period of idling more than a minute or so should be done at at least 1000-RPM, 1200 is better.

Every aspect of an engine is better at a higher idle RPM.

I've heard of regulators failing closed, and burning up all sorts of stuff - always run a fuse off the alt!

Just recently, the regulator on the wife's 91 Dodge/Cummins failed "closed" and immediately dramatically shot both new Sylvania SilverStars and boiled the big Group-31S nearly dry during the last three miles getting home.

An alternator/regulator can fail in the middle of the night with no one around and bad things happen.

Many is the house, garage, and barn that have burned to the ground due to an alternator shorting out while everyone is in the bed asleep.

I was in our shop one night when the alternator on a tractor decided to short out; had I not of been right in the building when it happened, we would have lost the tractor and several others, some trucks, and the building.

Every bit of insulation burned off the wires before I could get a cable off the battery.


Along with fusing the main charge-wire from the alternator, a big cut-out switch should be installed in the main charge-wire and turned OFF any time the vehicle is left parked in a building.