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Old 02-17-2013, 04:00 PM   #1
jmix
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Default Should my lights be dimming??

I have two amps one being an Alpine MRP-M350 powering a 10" Alpine sub (running at 2 ohms) and the other being an Alpine MRP-F300 powering a set of Alpine components in the front and type-s's in the rear. Now I've done the big three with 4 gauge wire and added about 8 more grounds in the engine bay with 8 gauge wire. I also took all the stock grounds and cleaned them up. I added a forester 110 amp alt and an optima red top. The amps have 8 gauge wiring running to them (one of the amp manuals said to use that size and the other said nothing). I also have an Alpine head unit and when I turn it up past 17 (max I go is 21 out of 35 with both amps being at half gain) my headlights and my odometer light will flicker/dim. Do I really need to up size my alt even more? I don't feel that I'm listening to it ridiculously loud or anything by going to 21 on the HU. Now I do believe I have a bad RCA cable on one of my components but would that cause the problem I described? I'm hoping it's just the RCA bad and not the head unit as I swapped the cable from left to right and it followed. Thanks for any HELPFUL input.
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Old 02-17-2013, 04:39 PM   #2
S1CkWrx
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go to 4gauge wire. 8 gauge is too small.
make sure all grounds are 100% perfect. even if you have to sand a little paint down to get a better ground do it
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Old 02-17-2013, 05:15 PM   #3
jmix
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So you don't think it's an issue with the alt being too small? That would be good since I don't want to drop a couple hundred on a new alt.
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Old 02-17-2013, 06:03 PM   #4
jmix
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another thing to note is that I don't think the terminals on the amps will accept 4 gauge wire. I'll have to look and double check but I think that when I installed them the 8 gauge fit the terminal hole perfectly.
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Old 02-17-2013, 06:08 PM   #5
jmix
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never mind, i just found these wire gauge reducers.

http://www.sonicelectronix.com/item_...22.html?from=3
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Old 02-18-2013, 11:14 PM   #6
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8 awg wire is plenty for the RMS of both amps combined. Check all your grounds for a solid connection make sure your battery terminals are free of corrosion and are making good contact. Maybe try adding a capacitor
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Old 02-19-2013, 05:47 AM   #7
jmix
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So does anyone know if a bad RCA could cause the issue? I'm going to check the grounds but they should be good since I cleaned them all and added extras in the past year. I would rather not spend money on 4 gauge wiring so if 8 is fine that's cool.
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Old 02-19-2013, 10:03 AM   #8
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I dont see a bad RCA cable causing your lights to dim.
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Old 02-19-2013, 05:05 PM   #9
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Check your battery too. Old batteries are going not going to be able to run the power you need. I always run coppertop. Only battery I know of that is actually to factory spec battery.
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Old 02-19-2013, 05:07 PM   #10
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Quote:
Originally Posted by jmix View Post
So you don't think it's an issue with the alt being too small? That would be good since I don't want to drop a couple hundred on a new alt.
The alt size is fine for your application
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Old 02-20-2013, 10:01 PM   #11
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check grounds, sand any connection spots and maybe add a little di-electric grease.
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Old 02-20-2013, 10:29 PM   #12
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A 110 amp alt should be plenty big enough for the amount of power your running, actually the stock alt would probably have been ok, but it never hurts to upgrade. It also sounds like your wiring setup is pretty good. Do you have 4ga wire going to a distribution block that splits it to an 8ga for each amp? or do you have 2 separate runs of 8ga? how are the amps grounded? Have you had your battery checked? there could possibly be a problem with your battery or the alt itself.

You should not be getting significant light dimming with the amount of power you have, even with a bone stock electrical system, much less with the upgrades you've done.
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Old 02-20-2013, 10:49 PM   #13
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Whatever you do dont do this..

Quote:
Originally Posted by Van Johnson112 View Post
Maybe try adding a capacitor
Like others have said your stock alternator should be fine for your power requirements. You need to find the source of the problem rather than put a band aid on it.

Also just curious, does the dimming occur only while stopped or also when you're driving
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Old 02-21-2013, 09:22 PM   #14
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Yeah a capacitor will fix you up. Recommended 1 Farad for 1000W of power. Its easy to wire up
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Old 02-21-2013, 09:44 PM   #15
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Quote:
Originally Posted by dirty wrx View Post
Yeah a capacitor will fix you up. Recommended 1 Farad for 1000W of power. Its easy to wire up

GOD... I just can't even look at this forum anymore
guess everyone has to learn the hard way.
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Old 02-22-2013, 12:04 PM   #16
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HAAAHAHHAHAHHAA Caps are BANDAIDS!!! They dont fix a thing. They are merely for show!
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Old 02-22-2013, 12:33 PM   #17
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I would go to an audio forum for audio advice, there is a lot of crap floating around on here
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Old 02-25-2013, 10:51 AM   #18
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Typically, any issues with dimming is because your sound system is sucking power from your car and the alternator cannot supply enough electricity to all the cars accessories...so when you turn up the volume your amp steals power from the headlights/interior lights.

Stock amps are good up to about 1000 watts RMS , but I would suggest a bigger gauge wire for your big 3 (the bigger the better) and amp power/ground cables. That might help the dimming but maybe not eliminate it. Check grounds again.

CAPS SUCK and a spare battery does not help either (just another thing your amp would have to supply power).

High output alternators are expensive and if they are your last resort, just run thicker gauge wire.

Also check your battery, could be low on voltage

Last edited by razzmatazz_21; 02-25-2013 at 10:56 AM.
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Old 02-25-2013, 12:44 PM   #19
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Old 02-26-2013, 10:08 AM   #20
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Quote:
Originally Posted by S1CkWrx View Post
HAAAHAHHAHAHHAA Caps are BANDAIDS!!! They dont fix a thing. They are merely for show!
Pull the start capacitor off a motor and tell me how good it works with out it...

Than again the alternator you swapped could be on its way out. If a 110 amp alt can't keep the battery charged enough for 550 watts of audio and maybe another 200 for accessories.

Last edited by Van Johnson112; 02-26-2013 at 10:20 AM.
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Old 02-26-2013, 11:36 AM   #21
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A capacitor will only strain your charging system more, another device to power/charge. Capacitor should only be used for stiffening the volts to the amps.
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Old 02-26-2013, 02:21 PM   #22
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What followed the RCA swap? You lost me there. You said you switched the RCA from left to right and the problem followed. Do you mean the lights on half the car dim?
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Old 02-28-2013, 07:01 AM   #23
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Sorry for the late responses, I didn't think anyone had replied to this thread lately and I haven't checked it...I swapped the RCA cable on the amp for my components since my right front speaker was cutting in and out so I could see if it was an issue with the speaker or the cable/headunit. It moved to my left speaker when I did so leading me to think it's either my cable or something with the head unit. I'm not considering running a capacitor and I'm not really trying to see/read a big debate about it in this thread. I have the amps running their own 8ga power wires from the battery and then I grounded each amp under the legs/feet of the front seats as my amps are mounted under them(one ground under the driver's and one under the passenger's). I cleaned the paint off when I did that and put dielectric grease on those areas as well. It seems like the lights are dimming moreso when I'm cruising but I think they do it as well at a stop.
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Old 02-28-2013, 07:03 AM   #24
jmix
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Also the alternator and battery were just replaced again. I initially thougt it was a voltage regulator problem with the alt so I sent it back to maniac electric for a warranty swap and I had an issue with my optima not holding a charge so I just sent it back for a warranty exchange as well.
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Old 02-28-2013, 11:14 PM   #25
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You need to run either a 2nd battery or a cap to help. I had the same problem when i had my 2 15's and a 2,500 watt amp. I am sorry to tell you this but you will more than likely have to do this to make it stop. The amps draw more power than what is being stored/generated and for that split second leaves the battery lower than it should be. Unless you spend huge money on an ungodly alt I can't think of anything else. Oh ya a bad ground would cause the amp to cut in and out. If I think of any other solutions I will let you know.
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