Thread: Stereo System Thumping = Lights Dimming?

Originally Posted by KeithGTP03

Its well documented of these cars and their bad grounds...but you can not track them all down. Every Gp Ive owned has dimmed under amp loads. I would like 1-800 to post the setup of the friend thats runnin the 2500 watts with no dim on a stock alt. And how the dimming was solved. ( without auxiliary batteries)

There's no secret to his setup. He has 4 1/0 runs to his trunk and did the big 3. He has an extra battery in the trunk but that's for the competitions where the engine is off. Just as it's been mentioned already, grounds are typically insufficient; quality vs. quantity.

Surface contact, locations of actual groundings, corrosion, proper crimps/soldering, etc. These are all issues related to insufficent grounds...even nickel plating copper wire. Personally, I have run class a/b amps that presumed output of almost 1500 watts altgether. I did not have dimming issues unless clipping sub signals. I upgraded the battery to fender ground and added an 8awg wire to a strut bolt. The amps in the rear are grounded to the strut tower bolt as well. Since then I've moved to a new class D amp that is 150x6. It's been tested to put out almost 186 per channel and 192watts a-weighted.

Anyways, I don't have dimming issues. But I've even gone as far as using large washers and scraping off paint in order to increase surface contact for my grounding points. The other guy I mentioned used 1/0 wire from the welding section in lowes or something rather when he did big 3. I've posted his process for melting solder between the wire and terminals too if you feel like searching.

scratch that. i have very slight dimming isses when idling at ~700rpms. It was getting that low when my egr valve was problematic. But then again, even the fan blower was having problems with output at that low an rpm. Also, I had calculated ~30 to 40amps worth of draw, depnding on music, with the class a/b amps and my head unit cranked. The amplifiers' internal fusing combined for 170amps total. I had the 4awg wire for power fused at 80amps next to the battery. Just because you're rated for 728448 jigawatts doesn't mean you're using it. Oh...and a-weighted i was hitting ~115db's and I could get as high as 130's for c-weighted.

Originally Posted by zx7r4u2nv

^^^^^ good setup. Ya, dimming lights could be many issues but usually not enough power on supply.

You can only pull what the system is grounded for. If you pull more than that your voltage can bottom out...causing your lights to dim.