Just for reference, I have a 2005 Grand Prix GT, and I do have quite a bit of background knowledge on car audio and electronics/circuits to begin with, so even if a suggestion or such that you have is complicated, I will probably understand or at least learn quickly. I'm no newb to electronics, one of my passions
Now I know the deal with capacitors in regards to car audio and high powered systems, as in they aren't worth it/will not REALLY do their job unless your electrical is already sock solid. If they help dimming on an undersized system, they're also putting much more stress on your alternator, and better grounds/connections will probably help.
I run about 1400 watts RMS strictly to my subwoofers, all OFC 1/0 gauge welder's cable, dedicated ground directly from alternator casing, silver soldered terminals, a dry cell in front and back, 250A max DC Power alternator etc. I made sure I did it right, because I'm prepping for a 3500 watt RMS build next year (I just may document it if people are interested) But as most people know, that still won't eliminate all headlight dimming on all cars, and it doesn't on mine, because headlights tend to react to even the smallest voltage changes.
My system charges at right about 15v, and only drops to a bit above 14v during sine waves, maxed out with no clipping. This is enough for noticeable headlight dimming. Now I found a guide to upgrade stock headlight wiring using some larger gauge wire and SPST relays, with dedicated power and grounds run from the battery, using the stock circuits simply for turn on/turn off leads, as shown here by one of our own member's personal website (for anyone interested in diagrams):BACKINBLACK's Grand Prix electrical mods page... You'll find the link below on that page along with many other very helpful electrical mods (like adding 2nd gear start!). My only initial modification is using a dedicated ground from the negative post of my front battery so the ground is as beefy as the power wire, and of course separate circuits for highs and lows as 04+ GP's have separate lights for high's and low's (why can't I add my car and mods to the "My Garage still?!).
Now that mod will brighten your headlights a bit/make them slightly more resistant to dimming due to higher voltage/lower resistance in the wires. But in order to COMPLETELY eliminate dimming, I'd like to wire capacitors in line as well to make them... "dimming immune" so to say. I figured a capacitor wired across the ground and power inputs (before the relay) as well as a diode on the power circuit would do just that. I just have a few questions before I "embark" ion this project with in the next week or two when it's not pouring outside.
1. What size capacitor do you think would have enough capacity to keep the voltage up even on longer bass hits? Sine waves are another thing completely, just those long loud bass hits in actual music. A 25V capacitor will be safe in terms of over voltage, but what capacity in microfarads do all of you think would suffice? I'd rather go a little big to be safe than too small.
2. I remember back in my electronics class a few years back in highschool, my teacher (who really should have been teaching in college at least by how much the man knew, he's a role model of mine to this day) spoke of using resistors somewhere inline to keep the capacitors charged even when the circuit is off. Would anyone know where I would have to wire one and of what value in ohms?
Here's a simple diagram, taken from blackgp's website a modified slightly to represent what I'm going for, and so it's easier to see/understand/explain the layout for anyone willing to help or anyone who'd like to do this after I do it myself and report the results.
^The blurred out parts aren't too important, if you'd like to see what they are, the link I gave has the original pic which isn't all messed up, idk what happened when I uploaded it to Image Shack...
I really appreciate any help, and I am always welcome to constructive criticism, if there's a better way I could be doing this, then feel free to suggest/explain it. If this works (I have no doubts it won't, just have to make sure the wiring is correct), I'd love to make an actual write up of it with pictures, and I'll most likely do it to all of my car's exterior lighting since LED's react soooo easily to voltage changes.
P.S. Anyone know of switchbacks for my DRL's (the yellow/orange ones that double as turns) that run white, but flash ONLY amber, and actually have decent output? I'd like to run ones that actually are helpful and match the color of whatever I decide on for fog's. Either LED's as well or bright halogens that won't melt my housings, any recommendations for those things would be appreciated too