Lets start things off with the most info I can give. I have a 2006 Dodge Ram 1500 ST. It is a single cab 2wd with the V6 3.7L. The alternator is a 136 amp. The voltage regulator is built into the PCM. Now I am running a Soundstream PCX1500d and will be pulling the full rms (of 1500) during competition. I have a single run of 2/0 from front to back with 2 shuriken sk-bt60 batts under the hood. I am getting ready to do the big 3 any day. My current voltage is 13.8-14.1 on a normal day. When it is cold it will run 14.4. I want to increase my voltage to 15v. Now here is what I am currently investigating. I am in search of a wire diagram to find the feed signal from the alt to the PCM. Now my theory is that I can find a resistor of x size to make the PCM think it is running a lower voltage thus increasing my overall voltage. Now here are the questions. Is this first off just some insane idea I shouldn't be messing with or am I on a good starting path. Second what resistor values should I start playing with to change my voltage? Now keep in mind that this is just an idea and I am simply trying to get some external input. I have not done anything at this time to the alt. or PCM. Thanks.

I have uof my good friends learned of it on a Subaru forum and told me about it. Is it safe long term? I do not know the answer to that. He has done it and it's been 5/6 month with no problems.

I am in the same boat as I want my alt to charge higher like it does when cold all the time. Currently it charges 13.6 hot and 14.7 when cold. I am going to try the VCM from XS Power personally. It allows you to set a voltage and keep it there. I hope this does the trick.

I have uof my good friends learned of it on a Subaru forum and told me about it. Is it safe long term? I do not know the answer to that. He has done it and it's been 5/6 month with no problems.

I am in the same boat as I want my alt to charge higher like it does when cold all the time. Currently it charges 13.6 hot and 14.7 when cold. I am going to try the VCM from XS Power personally. It allows you to set a voltage and keep it there. I hope this does the trick.

I looked at that as well but it was only listed for GM's.....

they are making them for all kinds of vehicles.l it just takes time

I can see where it would work quite well, like it is for lancelot's friend. To find out the value of the resistor you need, all you need is Ohm's law, BUT if you want to make it adjustable all you need is a potentiometer. If you wire the potentiometer as a rheostat, you can turn the voltage up and down and adjust it a little if you'd like to.

Here, found a good page that explains the operation of a potentiometer as a rheostat even. Thought it might help: Potentiometer as a Rheostat

Alton you are the man. Thanks for the link. I came across the potentiometer once in my searching but never found that link. It explains a lot. Thanks again.

You're welcome. If you go the potentiometer route they're cheap enough I'd buy several difference sizes (i.e. 50ohm, 100 ohm, 500 ohm, 1k ohm, etc.) so that you can get the best adjustment without making it real touchy and being able to turn it up to say 24v by accident. I doubt the regulator could hit that mark but to be safe start with the smallest.

That was exactly what I was thinking. But now the problem is the search for the wire that he PCM gets it's voltage signal from. I may be over thinking this because it also makes sense that it would be one of the wires on the harness on the back of the Alt. itself.