by Son of Zarn » Thu Mar 05, 2009 3:20 pm
If you're trying to cure light dimming problems due to a high output sound system, then the only way is to completely isolate the amplification power supply from the vehicle's charging system. Any change in voltage in the charging system due to a load change is easily noticed as a dimming or brightening of a light that is powered by the same charging system.
Installing a higher output alternator, even a 500 amp monster, won't completely eliminate dimming as the cicutry inside it must adapt to the changes in load. This adaptation is not instantaneous where your eyesight is concerned, nor can the alternator sustain a full load output, (as in the case of loud, low frequency bass notes) 100% of it's operational time.
A capacitor can help smooth out the voltage changes but again, your eyes are very sensitive to subtle changes in light intensity.
What I suggest is that you install a second charging circut (alternator and battery combination) in addition to the capacitor that you already have:
Run new heavy gauge wire for 12V+ power and ground. Keep the 12V+ power wire completely insulated from any of the vehicle's power (or for that matter, ground) wiring. Use an inline fuse or circut breaker which is rated at no more than 10% of the total of the amplifiers fuse ratings and mount it close to the new battery on the 12V+ cable. Run this cable to the cap first, then from the cap to your amp(s). You can still use the vehicle's chassis for ground but you will need to run the heavier ground wire from the chassis to the new battery and alternator and sufficiently large ground cable from the amp(s) to the chassis and from the cap to the chassis.
Unfortunately, the most difficult step is mounting another alternator to the engine. Difficult, yes but not entirely impossible. I'm sure someone can fabricate all the necessary brackets to do this for the right price and you may be able to find a small case high output one-wire alernator or one with with a remote voltage regulator. Again, this won't be cheap but it's the only 100% cure.
As for the second battery and isolator idea, if you plan on driving for extended periods while listening to music at high volume, you will have to eventually switch between allowing the alternator to charge the vehicle's main battery and the ampifier's battery. Each time you do this (or if it has automatic switching capabilties) you will see the lights dim or brighten.
