Light dimming question

Discussion in 'Automotive Electrical' started by 6.5ldiesel, Jan 16, 2011.

  1. 6.5ldiesel

    6.5ldiesel Full Member

    I am running a total of 3,000w RMS in my system, all high quality equipment. Rockford amps, and 12w7 subwoofers, and ID components.
    I have 2 1000CA duralast batteries under the hood, and a 220 amp HO Alternator. I do not have a crapacitor and am running 1/0 gauge wire, the ground is about a foot long for both amps.
    My lights dim, but the voltage doesnt drop below 13.5 volts on a good thump...

    Anything to get rid of this annoying problem?

    My theory is the batteries are not discharging fast enough, or the wire? (It is XXX brand)
     
  2. morespl

    morespl Full Member

    how do you know your voltage is only dropping to 13.5

    Were you measuring with a ddm if you were it might not be fast enough to pick up the real voltage drop and also your system alone is roughly pulling 222 amps of current at 13.5 Do you just have the one alt. Your car needs the alternator that came with it which is usually 80 to 110 amps depending the vehicle. So your batterys are always gonna drain if you burp the system for a full 5 minutes it will probably drop alot lower. My bet is that unless you run three batterys and the proper amount of alternator the dimming will go away.but I doubt anything else will completley stop the dimming.
     
  3. 6.5ldiesel

    6.5ldiesel Full Member

    the 3k w RMS is with about 1/3 of that is headroom. I was using a fluke meter to test the voltage
    another note, it dims on half and full power... at half it doesnt drop below 14.2 but still dims the same

    I have decent experience in the car audio field and this is just a pain in the A...
     
  4. TheViking

    TheViking Well-Known Member

    morespl is correct in the fact that most DMM's will not respond fast enough to detect transient dips and peaks, at least the display isnt fast enough. If your DMM has a min/max recording setting use it and it will show you what is going on. As for the dimming lights, be SURE you have done the big 3, and be sure both batteries are grounded very well. But really, in any large sytem dimming lights is going to be an issue. One of the ways to help alleiviate the problem is to have a battery close to the amps.
     
  5. morespl

    morespl Full Member

    yeah ck your grounds

    make sure there grounded in the same place the shorter the better like viking said but I have never seen a system where the light would not dim my buddy had 5 kinetic hc 2000s two ho 300 amp alternators on 5500 watts he still had dimming. I have a 300 ho alternator three kinetics 2 hc2000s 1 hc 2400 and a estactic bat cap 300 lights still dim I'm running 4800 watts rms. Also once your batterys discharge they will keep dimming til they recharge fully
     
    Last edited: Jan 16, 2011
  6. 6.5ldiesel

    6.5ldiesel Full Member

    I used that min feature, I do not have my amps grounded to the same spot, each are grounded directly to the floor where the metal is double as thick with a 1/2 bolt
    It is impossible for me to fit another battery in the back by my amps, there is absolutely no room, unless i have one small enough mounted to the side of the platform (will it take the vibrations?)
    Both batteries are grounded directly to the frame AND engine, EACH, they are connected in parallel and the one batt has all the audio hooked into it, the second battery is hooked into that (Came stock with 2 batteries)
    The stock wiring was 2 gauge, I added 1/0 gauge to that in different grounding points.
    The amps are being fed the power they need

    Ive seen systems that didnt have the dimming, and ran twice the power i have, with 2 batteries and a 200amp alt. (But with all memphis wiring)

    This is why I think its the cable ive used.
     
  7. morespl

    morespl Full Member

    doubt this

    Ive seen systems that didnt have the dimming, and ran twice the power i have, with 2 batteries and a 200amp alt. (But with all memphis wiring)

    This is why I think its the cable ive used.

    6000 watts did not run off that with no dimming.If it did it was only running for a couple minutes if you think its the wire double it up the grounds are supposed to be ran to the same point I have mine grounded to the frame the less weld joints in between the better.What kind of batterys you running.
     
  8. tommy2tone

    tommy2tone Full Member

    Maybe I'm stretching here but what about the big 3.Do you have it done already?90% of the time,it's the fix for this type of problem.
     
  9. 6.5ldiesel

    6.5ldiesel Full Member

    Duracrap 1000CCA (largest that'll fit under the hood)
     
  10. 6.5ldiesel

    6.5ldiesel Full Member

    Ive used 1/0 gauge on each battery ground to the frame, and motor per battery and one battery is connected to the alt with a 1/0 gauge wire
     
  11. morespl

    morespl Full Member

    If you have the big three

    Try to run two deep cycle competition car audio batts ground the amps at the same point You could also have a week link at one of the grounds did the lights always dim theres just to many options It could be most people eventually give up because the electrical system is so expensive.I would also have your batts load tested prove if they work can't remember if you did that alreadt as I'm typing
     
  12. TheViking

    TheViking Well-Known Member

    Sounds like you got most of the bases covered, But i would like you to do one more thing....run a ground cable from the battery(s) to the actual BODY of the vehicle. The way I understand it you are grounded to the frame, which IS good! But the amps are using the body to transfer their electrons. And the body or cab has lots of rubber isolation from the frame and chassis. Another option.....run ground cables from the frame to the body near or at the amps ground points..
     
  13. 6.5ldiesel

    6.5ldiesel Full Member

    Ive never thought about that, I will be giving this a try!
     
  14. 6.5ldiesel

    6.5ldiesel Full Member

    I just load tested each battery individually with the starter, Batt one dropped to 10.5 V which i consider VERY healthy

    Batt 2 dropped to a disgusting 3.5 volts

    Should i save my money up for 2 kinetics, or other car audio batt or replace the 1 with the same batt? (one is 1 year old, bad one is im not sure of)

    Found my problem, but I will do what viking suggested.
     
  15. morespl

    morespl Full Member

    let us know how it worked

    Always interested in the end result
     
  16. 6.5ldiesel

    6.5ldiesel Full Member

    Id like to update, I put a 1/0 cable directly to the frame directly to the cab. Before I did this it would read 2-2.5 ohms from where i grounded the amp, to the frame (sanded down)

    I installed the wire with 1/2" bolts and star washers, sanded down and it reads .1-.2 ohms, perfect
    My voltage will drop to 14.2 at full blast now, with the junk battery and HO alt
    If you have an older chevy truck id suggest putting a frame to ground cable, don't know if I was suppose to do originally but it helped, alot.
     
  17. TheViking

    TheViking Well-Known Member

    outstanding. glad to hear it helped