Dual Alternators?

Has anyone here ran dual alternators? I was wondering how difficult of an install that would be and if i would lose anything in doing so. This is going in a 99. Thanks and let me know.

Instead of adding the complexity of installing dual alternators, why not just add a bigger alternator? They sell alternators that are over 200 amps.

Who sells them? I would definately be interested in THAT.

I have been looking for a while, but not too heavy yet.

I have given thought to the dual alternator thing, but seems too complicated and highly custom, too much complexity off road.

The simpler a machine is, the less likely it is to break down.

My 2 Cents...

I have a couple of them, but the place that I bought them from isn't in business anymore. I'm not surprised. Both broke right away, and one was packaged with a staple going right through the regulator. That company kept me waiting a month everytime I placed an order, but charged my credit card immediately. They also made me pay for shipping the regulator back to them with the staple in it. Try these places: WWW.Alternatorparts.Com.
WWW.Powermastermotorsports.Com. WWW.Taeservice.Com/home.html?src=overture&OVRAW=alternators&OVKEY=alternator&OVMTC=content.
WWW.Wranglernw.Com.
I haven't bought any parts from these guys, so if you have a positive, or negative experience with any of them, please let me know.

THANKS!

Ill get back with you.

I'm running dual yellow top batteries right now.

I am running dual 15 inch electric fans on a temperature relay and 4 cheapie off-raod lights on the front.

This destroyed my old dual batteries (duralast) so i got the deep cycle Yellow Top Optimas. When I have to ride at night, or in the rain, it drains pretty good, and I am worried I will destry my new ones too.

Thanks again

How many amps is your stock alternator? Are you using an isolator with the dual battery system? If so, how many amps is the isolator rated at?

I am using the stock configuration, with the Batteries wired in parrallel (hot to hot grnd to grnd).

I think its a 90 amp alternator, Mountaineers ahd the bigger ones... maybe even 100 amp...not sure.

It has no problem with it all, the ammeter doesnt move at all when I turn on the lights and windshield wipers and stuff...I am just worried.

No I am not using an Isolator, Should I be??? What does it do?

In those links, I saw alternators with ratings between 160-350 amps! I wonder how they manage to get that much power out of one of those with a stock case that originally had about 130 amps? The ones that I have are rated at 225-275 amps. I have a rebuilder test them, and said that his machine didn't go that high, so he couldn't verify the exact output. He told me that the rotors are stock, but the stators are custom wound. For some reason, the rotors in the ones that I bought only lasted about a month, and I had to replace them with stock ones. The rebuilder charged me $50 a rotor. The brushes, and holders burned out within a year too, and were replaced with stock ones. He said that those parts were also stock parts. This makes me think that if you order a performance stator, and diode trio, and just add it to your stock alternator, you could probably get a high current alternator at a much lower cost. I assume that the diode trio is not stock, since it has to handle twice to three times the amount of current. AlDive has a write up on a performance pulley for about $40 that makes the alternator turn a little faster at idle, and at higher rpms to avoid a low voltage situation while at idle. The pulley is a little smaller than the stock one, so you would need a smaller belt.

Definately something to check out....I will do some research about that one, since $369.00 is hard to come by right now.

You should use an isolator for the batteries. The second battery should be wired to your accesssories like lights, and other high current draining things. The other battery is your primary battery for the engine, starter, and stock electronics.

Check this thread: http://www.explorerforum.com/forums/showthread.php?t=159655, and my post #14 with diagrams of a dual battery wiring schematic.

I see your point...

That way if one of them gets drained at least you can still crank up and drive home, your accessories dont effect your starting capability....

Do you know a good place to get a commecially built isolator, or is that something I need to build myself?

I will research it out, too. Thanks for the good info, I will work on this immediately.

Harbor Freight, AutoZone, PepBoys, and J C Whitney sell isolators. With an isolator, both batteries charge simultaneously, but don't drain off on each other if one is a little low from a current drain. They are isolated. That is why it's called an isolator.

Well i need dual alternators in order to run a 16 volt car audio system.

Not necessarily. There is someting called an active inverter that steps up 14.7 volts to 16 volts, but has a small current drop (because of Ohm's law). An active inverter is a dc-dc inverter. It takes 14 volts dc, inverts it to ac, steps it up to 16 volts, and then rectifies it into dc again. A passive regulator only regulates when the voltage sources (goes up), but does nothing when it sinks (drops down). An active regulator performs both functions. It is actually similar to the power supplies in desktop computers which work by pulse width modulation (PWM). Some newer style voltage regulators in cars work on a similar principle (active regulation), but most still use linear regulators that are passive.

I think expo 5.0 might has/had a dual alternator setup at one point. Try PM'ing him.

The battery splitter/isolator is definitely the way to go if you are using more than one battery. The safety side alone would warrant it so you do not kill your starting battery. a larger alternator may help, even a lot, but wire size and proper grounding is also very important. The stock wiring will only carry so much amperage before the voltage drops on the hot and ground circuits kill much of what your alternator is trying to give you. Try upgrading the wiring before you through a bigger alternator in the mix you will be pleasantly surprised. Here is a web site where you can plug in the numbers and see the voltage drop per foot with the amperage you are trying to push in a 12 VDC circuit.
The calculator is toward the bottom of the page.
http://www.powerstream.com/Wire_Size.htm

I remember an advertisement from JC Whitney a long time ago about an alternator that had dual outputs. That would simplify things greatly, since you wouldn't need a dual battery, and isolator. They also had one with dual 14.7 volts DC, and 120 volts AC outputs. I don't know if they still sell them.

West Marine has very good dual batt. isolators and switches. All marine grade.

Mutineer said:

Do you know a good place to get a commecially built isolator, or is that something I need to build myself?

Click to expand...

Any good boat shop will sell them (E&B Marine, West Marine, Boat US all come to mind). Any boat with dual engines will have one installed. They also make a manual one, (Which I had on my boat) but that would be a pain in the butt on anything less exposed than a tube-framed rock buggy.

-Joe