Dimming issues.

[Frankensuby 10+ year member]

So, did Big 3. Actually made it the Big 5 with some extra connections.

Still dims at 550 watts or more, 3k rpms (70 amp alternator). So, my next question is...Should I just run a ground from my trunk to my Negative Terminal? I know I have heard of comp cars running straight to the battery, should I?

I just feel like there has to be something inefficient with my Big 3, because others with same year/model/type car have no dimming up to 1k on stock alternators with big 3. My voltage only drops to 12.5's at near clipping, but the lights dim bad.

I also have roughly 75 feet of 4 gauge lying around //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Thoughts?

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[audiolife 5,000+ posts]

could be a slow regulator

 

[Frankensuby 10+ year member]

Alternator is 21k miles old, and it has been doing this since I got the system installed (roughly 8k miles). I don't bump loud for long.

My alternator adjusts it's overall charge in seconds after I turn it up (Ie initial few hits drops the voltages low12.5, but after a few seconds it jumps up to 13.2+ semi-constant)

The reason I am thinking that my Big 3 needs a direct to gound is because new cars are basically glued together anymore, and there are alot of metal parts held in by 2 screws and then body sealer. I'm thinking that because I'm not 100% attached into the frame of the car, it isn't as efficient as I'd like it.

 

[audiolife 5,000+ posts]

sounds to me like it is the regulator. not saying its bad its just how its designed to work.

 

[blackbonnie 5,000+ posts]

what size wire did you use for your big three?

 

[Frankensuby 10+ year member]

4 Gauge, MORE than enough for the power figures I'm pushing. I ran an inline fuse of 125 amps I believe.

I'm even more concerned because I'm soon to be pushing another 200 Watts RMS total, which will really bugger up the lights.

 

[blackbonnie 5,000+ posts]

why would you not use 1/0 wire. you will definately get more current to your battery. i suggest replace it with 1/0 and you shoudlnt see any dimming.

 

[Calikid 5,000+ posts]

4 Gauge, MORE than enough for the power figures I'm pushing. I ran an inline fuse of 125 amps I believe.
I'm even more concerned because I'm soon to be pushing another 200 Watts RMS total, which will really bugger up the lights.

u should of used 1/0, on most cars they come with 6 gauge from factory so going from 6 to 4 wasnt a big difference.

 

[audiolife 5,000+ posts]

if you want to test what it is use a 30 second test tone if it dims then brightens back up to where it should be then it is what i thought....

 

[Frankensuby 10+ year member]

why would you not use 1/0 wire. you will definately get more current to your battery. i suggest replace it with 1/0 and you shoudlnt see any dimming.

I actually made a thread for another forum regarding this. The basic reasoning is that my longest stretch of 4 gauge was 13 feet long. Using the table regarding power capabilities of 4 gauge over a 20 foot run, I was in the clear with some headroom. I have 2 class A/B, with one being an efficiency of 68.2% on bench sheet. The other I'm going to assume is 50% or so. thats about a combine load of 59% or so.

Power I'm actually using is 760 RMS with sub and Speakers at peak volume. That comes in UNDER the rating of 1000 watts at 50% and 20 feet. The amps total capability is at 1,100 roughly.

My math:

13/20= 65% of total 4 gauge spec is being used.

.35*1000= 350; 350 + 1000 = 1350 total watts allowable for a 13 gauge run of 4 gauge at 50% efficiency of amps. add the 10% or so differential, makes it 1385 total.

This is all assuming I understand the nature of runs, and what I'm building off of.

My replacement amp is going to bring my numbers up to a possibility of 1700 RMS //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif , so at that point I'm going to double run everything in the car. I'm actually only going to use 900 RMS of that system until after college //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

But, that basically is my reasoning for why I chose 4 gauge over 1/0 for now. I also had a tremendous deal on 100' run of 4 gauge.