Why do my headlights dim when my sub-woofers start to hit?

Question

Whenever i turn up my sound and my sub start to hit out bass, my lights dim. Is this because of low battery power or because of a less powerful amplifier. If i buy a better amp, will it stop dimming? Or should i change the three grounding wires? If so, please explain the steps to me.

Answer 1

Well you have the basic idea right in terms of the Big 3 wires, i cant explain to you in detail how to change it but try this site
http://www.the12volt.com/installbay/forum_posts.asp?TID=73496&PN=1

Basically when bass hits, it draws so much current that a voltage drop occurs therefore it will reveal any weakness in the car's electrical system. Upgrading the big 3 along with your amplifier wires to a lower gauge will help ease the current demands and should be first order of business. (make sure your ground wires for your amp is properly grounded, sand the area if possible) ask your installer if unsure. A capacitor should be next in line if problem persists and last resort usually is changing to a better alternator but that is if you are competing in SPL contests, etc.

Hint: your battery is only needed to start the car (have it checked just in case), it becomes just another load for the alternator to charge once the engine is running.

Answer 2

Quite simply, your electrical system cannot handle the load you are putting it under and the voltage is dropping.

The first step would be to do the big three. This is the wiring under your hood. It will let the electricity flow through your system with less resistance and can alleviate, if not eliminate the problem. Google "big three" and you will find plenty of answers. Also, you might want to consider getting bigger power wire if your current wire is too small.

If that does not fix it, you need a more powerful source, i.e. an higher output alternator. This can be expensive, so make sure you try the first step.

If a new alternator does not fix it - a new battery is in order. Although hopefully your problem is fixed with the first step. Whatever you do, don't buy a capacitor. It only strains your electrical system further. A typical 1 farad cap can only provide a second's worth of electricity - so once it drains, it just puts more stress on your alternator and battery.

Answer 3

I had the same problem for awhile. It appears that the altenator is one source of the problem. You see a typical altenator is put on a vehicle to run only what that car will use at max. with all accessories running, for example a/c,headlights, etc. you will need to upgrade your altenator to one that can put out double the amps of as so your altenator does not have to burn up and die from trying to fight with your stereo system and vehicle demands. Another thing to consider would be to add a second battery and place it next to your amp.This would of course need to be wired in series with your existing battery. Most shops can do this fairly cheap. I tried using 2- 1 farad strike caps but the dimming issue never changed. Good luck on it.

Answer 4

Because the sub-woofers are drawing power from the electrical system, that the lights were using.

Get a new battery, and have your alternator checked. Also, don't turn on your stereo until after you've started the vehicle, and when you stop, turn the stereo off first.

If your lights are staying dim while driving, try leaving the stereo off for a while.

If none of this helps, trade in your sub-woofers for softer ones that don't need their own nuclear-reactor for a power supply!

Answer 5

The amp is not the problem you need to go and buy your self a capacitor.It is like having a another battery.You can buy one at wal mart.It hooks up to the positive on the amp real easy fix and your sub might even hit harder because the amp is getting full power.Good luck

Answer 6

Here is a guide that will help determine power wire size, correct gain settings and whether or not you need an alternator upgrade:
http://www.datafilehost.com/download.php?file=6d26c621

You'll need Microsoft Excel, a multi-meter (AC volt meter) and a way to burn an audio CD from an MP3.

If you don't have Excel, let me know and I'll send you the required info in an E-mail. [e-mail]

See my site for more info http://spkrbox1.spaces.live.com

Answer 7

Your lights dim because of the surge in current flow to your amps. In order to fi this problem, you need to get a capacitor, which stores up energy for when those low notes hit.

Answer 8

The power from the bass is drawing too much power from the battery causing the lights to dim. you need more total battery power.

Answer 9

The reson your headligths are dimming is becuase your battery dosent have enough juice going to your amp. You do not need a new amp. This can be solved by getting a capacitor from crutchfield.com or your local audio store.

Answer 10

It's your alternator, it's not putting out enough amperage. The alt. powers all your electronics and keeps your battery powered up. All the battery does is start ypur car so the alt. can kick in.