mine are the original that came on the truck from the factory. What amps do they put out? Does one back up the other or do they work simultaneously? Does this set up allow for more accessories?

Just trying to get a better understanding of this set up and what the limitations are. I have learned an awful lot from you guys here on the forum and this is another part of the truck that I need to have right. My voltage on the insight usually reads in the high 12s to low 13s. Sometimes I see a very brief drop into the 11s when at an idle. I have new Diehard platinum batteries with presently no accessories other than the factory Lariat package

 

I've been trying to figure out the same thing recently due to some power issues on my truck, so I'll pass on the info that I have.

The stock alternators on the 6.0 motor is listed at 110 amps, but that's the rated output at absolutely best case operating conditions (low temps and high RPM).

I believe that the dual alternator configuration uses the same 110a alternator, it just uses 2 of them, and the load on each one is managed by the trucks computer to try and keep them balanced - I'm sure that someone will correct me if I'm wrong on this.

In all actuality, the stock alternator running at the high temps seen in our engine bays will probably only put out around 60 amps or so at idle, and might see 80 at cruising speed.

I recently had an issue with my alternator and the battery light came on, so I started monitoring the voltage on my insight, and I'm seeing the same low, fluctuating voltages that you are (anywhere from 12-14). Since that kind of voltage swing shouldn't be happening, and isn't all that great for electronics, I did some testing and here's what I found....

The voltage directly out from the alternator is right at 14.1V and barely moves - this is good!

The voltage at the batteries is 13.6V +/- and barely moves - this is ok, though it could be higher. I'm writing this off to voltage drop along the small cable from the alternator to the batteries, and expect this to improve once I beef up the cable (that's in the works).

The voltage reading at the insight fluctuating like that must be either the way that its reading the data from the OBD port, or the way that the computer is providing that data to the OBD. I doubt that its on the truck side since if the voltage swings were really that drastic, I believe that the truck would be exhibiting some issues (which it isn't). That leads me to believe that the insight isn't just reading the voltage at a power pin on the OBD port, but is reading the voltage from the trucks computer, and its just not very precise (doesn't give me a whole lot of confidence on the other readings I get from the insight).

I wish I had dual alt's in my truck - I've looked into adding them, but it doesn't seem to be an easy "bolt-on" type mod, so probably will never happen. I am however upgrading my alternator to a high output one that is rated for 185 amps total, with 100 at idle, and upgrading the charge wire from the alternator to the batts, as well as doing the "big-3" upgrade.

A stock truck is probably fine with the stock alternator, and a dual alternator truck with no additional accessories is even better off, though I would still recommend the "big-3" upgrade and maybe the charge wire upgrade too.


Hope this answers your questions.



Good luck!

 

The top one is capable of putting out 140 amps, the bottom is capable of 120. Depending on electrical load, they will work together to put out up to 260 amps.

 

From what I recall, the bottom alt. works normally just like a single alt. and when needed the PCM controls the top alt. If my memory is incorrect I have no problem being corrected.

 

Money-Pit is correct 260 amps combined

 

so there is no need to do anything further unless you had need for more than 260amps. sounds like that was a good option to choose when i bought the truck. I had thought I would be running a winch when I ordered the truck and thought I would need the extra alternator Thanks for the clarification on how they run

 

I have the dual alts also and I see the volts swing from 13.1v to 14.1v on the Scan GuageII. JR2980 had the right idea, get the reading straight from the battery. Chances are it will be steady and a bit higher.

Would be interested in seeing the "big-3" mod.


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Big 3? What is that?

 

Maybe JR2980 can expand a little more on this.

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Well, I'm starting to be a little less concerned about the big swing in voltage that I'm seeing on my insight - seems like everyone else that's taking the voltage reading via OBD is seeing the same thing without ill effects. I feel pretty confident that as long as your output at the alt and at the batts is good, then you shoudl be alright, but I might add a gauge running straight to the batt to get a better reading.

As for the questions on the "Big 3" upgrade, you can find info all over the net (and even here at FTE) about it, and it can apply to almost any vehicle. Its essentially upgrading the 3 main wires in your electrical system since the wires are generally sized as small as possible from the factory in order to save money - if you're running alot of electronics (stereo, tv, etc), or adding loads to your electrical system (plow, winch, etc), or especially if adding a high output alternator, you should definitely do this upgrade or risk overloading the stock wiring and/or seeing degraded performance.

The wires you upgrade are the (1) alt to batt charging wire, the (2) batt to chassis ground wire, and the (3) engine to chassis ground wire. Now, on a truck with dual batts, it will be more than "3" wires, but you get the idea. How you upgrade them is your choice, and will depend on your load.

 

Thank you sir.

This seems like a good idea, I'm gonna put it on the "to do" list.



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