Does anyone out there have dual alternators or the 140 amp, and if so is there any difference between the dual, the extra-heavy duty, and the base alternator, and for what reason did you opt for the two alternators. I am going to order a vehicle next month and I am looking at the goodies list and this is an option I am unfamiliar with.

 

Hey Warthog, I just ordered a truck too. I think two alternators would be a good idea if your running electric equipment off the truck or you were running like 6 off road lamps. I decided against it because of the drain it would cause on overall horsepower, and its just another thing to break down.

 

I ordered them with mine. 6.0. If you do a search there is some other threads out there on this and the concesses was it a worth it. My thought is that is was a good backup that hopefully would not leave you stranded. With duel batteries in the 6.0, it makes sense to have duel alts.

Once you have spent 35-40k whats a few bucks more.

 

Yea, it would be nice if one was set up with a clutch, like an A/C compressor so you could turn it on and off as needed

 

dafuz....Is there that much of a drain on horsepower, like the A/C kicking on?

boomer21...I agree with dual battery/dual alternator?

Thanks to all...can't wait to order....!

 

I ordered my 05 with the duels. My main draw for now is the plow. I might add lights. + I think it would add some resale value. JMO. Tim R.

 

My 05 F350 PSD has dual alternators (bought from located dealer stock). I also thought 2 is better than 1 (guy thing).

Up side is higher/quicker charging, and it is NOT practical to add later (there are considerable differences in many areas). Recharge for short trips (to recoup the glow plug drain at start) and if vehicle has "more lights" is a plus.

Down side is that they both mechanically run although the 2nd one is seperately controlled by the ECM. Another issue is the HP loss (there is a second belt that connects the water pump to the 2nd alternator, if this was removed, the ECM may illuminate the MIL, not tested). The largest issue I see now, is the turbo outlet to intercooler pipe is crimped to about 1/2 diameter to allow wrench clearance for the 2nd alternator. I don't know how much impact this has on engine performance, but this is the biggest down side. My engine produces ~ 25-30 PSI boost, and I believe this is after the intercooler (at manifold), so it appears that this may not be an issue (looks bad though).

If it is ordered, that is a good thing. I'm OK with my duals and would have ordered them if I had not found a 99% correct vehicle on a lot (dual alternators were on my desired, but not essential list of options).

 

I don't think they work like that. I don't think a battery discharged by one start is going to draw any more current than one alternator can handle, and having two isn't going to somehow "shove" more energy into the battery faster. The point is to handle more sustained draw, like more lights, extra equipment, etc. As I understand it, most of the time just one alternator is actually enabled anyway, and it changes which one from time to time (every start?) There's also the plus of redundancy, though that only helps in some cases. If the primary alternator shaft physically siezes, you have worse problems than a secondary alternator is going to be able to help you with.


I don't think it's crimped down to anywhere near 1/2 the diameter, and I don't think the cross-sectional area is really reduced much if at all. (Air will flow through an oval pipe just as well as a perfectly round one.) Here is the pipe:

http://www.backglass.org/duncan/2003...oler_1_med.jpg

Duncan

 

Well, thanks for the info...I don't think I am going to be using the truck for lighting purposes, or for any type of work that requires a heavy power draw, but I tend to go with the theory that two are better than one, maybe it is a guy thing, thanks for the help...Brian

 

Well here's my $0.02,

I ordered the duals with my 6.0 because I plan (Springtime) to install a power inverter to power my camper. Probably about 3000W. Also as a Firefighter/Paramedic I have some aux. lighting and radios, which on their own wouldn't require more juice. The biggest thing, I think is I also got the aux. idle control to go with it. There are other threads about this, but it's (only) $300 for duals and idle control (each), but I think one relies on the other. The control will automatically adjust the engine speed to compensate for voltage/amperage requirements. Since it would be tougher to add later I opted for both. Glad I did. Also, the cool factor when I jump out of the truck w/the e-brake on in Neutral (6-spd) and 2 second later the idle jumps up. Kind of takes people by suprise. Been asked a lot, "what is that"?

Hope this helps,
Mike

 

I had a salesman discouarge me on dual alts. He said a guy came in wondering why he got such bad mileage <10mpg. They found out he had dual alts and was costing 1 or 2 mpg. What do you guys think of that?

 

Thats a salesman pitch. Not sure I would want one of them servicing my truck.

 

Shouldn't a pitch be to help sell equipment though. Not discourage it. This is not the same dealer as my post in the new buyer forum.

 

Any automotive alternator will not draw enough load to justify poor fuel mileage unless it is working so hard that it is in itself powering the whole vehicle. Common to popular belief an alternator is a battery maintainer, not a battery charger. This means it is designed to bring up the normal battery drain after starts, etc. But if an alternator is overworked too much it will fry prematurely. Case in point- anytime a new alternator is installed in a vehicle, the box it came in has a big bright note saying to fully charge battery before starting engine as if it is faced with that high of a load it will literally die instantly.

 

I can't imagine a second alternator hurting mileage that badly. I get 17-18mpg normal driving and 14 towing 8000 lbs. If what the salesman said is true, turning on the A/C should cost 3-4 mpg.

Mike