Alright. I read the replies but have been a little busy lately with work. I wanted to do a little research with this before posting a reply. I understand the idea about too much current or not enough current. But what I am am confused about, is these devices use the current needed, based upon voltage and resistance applied, correct? So since there is a dirty voltage from the vehicle, if I were to regulate that down to 9vdc, then place an array of LEDs, dependent upon forward voltages, in this case 2.4v, I should be able to place 3 in series with a 100ohm resistor correct? I am to understand that series shares voltage, thus the limitation of 3 LEDs in series to consume the bulk of the 9v source, with the additional resistance to control the current flow? Now, on to the parallel side of things... I can place led series' in parallel to split current on the source, correct? So in theory, I could place as many arrays in parallel as my source could support, right? Having that been said, I have rethought my plan and backed down the number of LEDs to 12, to make things more manageable, which brings my total current consumption to 240mA. I have spent a little time revises a new schematic, and will attach it below. I am hoping this will shed some light on what I mean to do exactly. In theory it works. What are the issues, if I can assure a stable voltage? I thought Ohms Law would ensure strict current control if I had control of resistance and voltage. Am I wrong?
I do not mean to sound contestant or arrogant. I am really curious, because this was the basic electronic principles I learned in class a few years ago. I want to make sure I got it right.
As for switching that array, which was what this thread was really about, I think I may have found the solution. I have been eying these little Reed Relays. Specifically one that has a 5vdc coil and nominal current of 20mA, which I thought was really cool, kinda like driving a LED. They have a diode built in to deal with the back feed issue AND only cost a few bucks. After I get some insight on this array issue, I think I will buy a couple of these and try them out. I have included them in the schematic.
Thanks for all of your help guys, I really do appreciate it. It is a learning experience for me, and I hope someone else can find the information useful too. Let me know what you think.