Dual Alternators - Diesel Forum

LariatPSD · 12-15-2006, 11:34 PM

My truck has just about every possible option except dual alternators. It was too late for me to order an '06 the way I wanted it so I bought the one I've got which is darn close. My voltage is always 13.6 - 13.8 but I'd love to see 14.4. Now, has anyone converted from single to dual? Any benefit vs a single aftermaket high output? Wouldn't duals cause significant drag on the motor? The pulley kit on my Mustang freed up about 10hp.
Thanks in advance.

SAVAGESAM · 12-16-2006, 07:29 AM

I've got duals and from what i've read here and IF i understand it correctly the alternators "take turns" doing the work unless there is a huge demand. AFAIK the one not putting out has very little to no drag at all. Cost would be prohibitive to convert, much cheaper to have a H.D. one made for you. Out of curiousity what kinds of heavy demands do you have?

Zj0187 · 12-16-2006, 12:06 PM

I have duals and I see anywhere from 13.1v to 13.4v thats all. (normal driving)

SPL2K · 12-16-2006, 02:43 PM

Adding the 2nd alternator will not increase voltage, only amperage.

You would be better off getting a high performance aftermarket alternator if you really "need" more power. Powermaster is the best.

ford_doctor · 12-16-2006, 05:01 PM

[ QUOTE ]
Adding the 2nd alternator will not increase voltage, only amperage.

You would be better off getting a high performance aftermarket alternator if you really "need" more power. Powermaster is the best.

[/ QUOTE ]

Absolutely!

The dual alternator set up is nice but it is near impossible to add it and would cost more than it's worth. Several of my customers had learned the hard way on 2004 trucks with respect to amperage and winter usage; running extra lights like beacons, strobes, salt spreaders and plows. Most had a specialty shop re-gut their alternators with higher output parts.

LariatPSD · 12-16-2006, 09:29 PM

Thanks Guys, sorry I didn't say why I wanted it. I'm running upgraded lights, a pair of off road lights (soon to be two pair), and around 1500 watts of stereo equipment with a 15 Farad capacitor. I wanted to maximize the the output of my amps and keep up with all the demand on my electrical system. My friend has a Silverado with a big stereo that consistently puts out 14.8-14.9 volts. That tells me that it's at least keeping up with the demand. Is there a way to bump Amperage as well as Voltage?

SPL2K · 12-16-2006, 10:24 PM

[ QUOTE ]
Is there a way to bump Amperage as well as Voltage?

[/ QUOTE ]

http://www.powermastermotorsports.co...ternators.html

RatherBNtheWoods · 12-16-2006, 10:47 PM

I wouldn't think you would/should raise the voltage, just the current charging capability. As for dual alternators mine usually run around 13.4-13.6v. The two alternators are wired in parallel so they simply share the load constantly. I think the Motorcraft batteries have a different electrolytic composition that requires slightly less voltage than some other batteries/vehicles.

ford_doctor · 12-16-2006, 11:46 PM

Controlling the voltage output of your charging system is very important and I urge caution if you attempt to raise it. The first thing is that the set voltage of the regulators in your Super Duty trucks varies with temperature and is typically higher in cold temperatures than in warm temperatures.

While higher output from the alternator(s) will aid in better charging of cold batteries in winter, too much voltage in hot weather can cause the batteries to over charge causing damage to them.

For those of you with diesel engines you need to know that excessive voltage can quickly damage your 12-volt glow plugs. During certain conditions, the glow plugs are on after the engine starts to reduce emissions. If your diesel truck is equipped with dual alternators, the PCM actually turns off the lower alternator to help prevent the possibility of such damage.