Headlights dimming because of subwoofer

[Sether]

Hey guys, just looking for some answers, I've got a Rockford Fosgate P3 12 inch sub with a fosgate r1200-1d Amp powering it. Well recently my headlights have been dimming pretty bad, with it, same with the dash lights. I've noticed very little dimming before but now its getting annoying. from my display in the car it says im never getting under 14 volts. I usually stay somewhere around mid to high 14 volts. Could be the battery because I dont even know how old it is. Any ideas guys on how to fix this *shoot*?

[96 SSEi]

fosgates pull lots of amps - I have an early 90's punch 45 ( 1000 w resistors in a 100 w amp - 45x2.

you may be overworking the system - alternator cant keep up with the draw. how much does the woofer pull? how are you setup?

check charging system or go back to stock.

[Sether]

fosgates pull lots of amps - I have an early 90's punch 45 ( 1000 w resistors in a 100 w amp - 45x2.

you may be overworking the system - alternator cant keep up with the draw. how much does the woofer pull? how are you setup?

check charging system or go back to stock.

The woofer has an peak of 1200 watts and is wired to 1 ohm so its reaching that 1200 consistently. Amp is bolted to a metal bracket in the trunk, which has a very short power wire running to the battery under the rear seat and ground connected to the same metal the amp is bolted to i believe. Could be the alternator cant keep up but I doubt thats the problem i mean the alternator is reaching consistent voltage on the meter in the car while its the sub is punching. It used to go lower then 14 volts but not it seems it will not drop under that yet it dims more. i still think it might be the battery because I do not know the age but do you have any ways of testing the charging system?

[RJolly87]

I recommend verifying the system voltage with an independent source, such as a Digital multimeter, or other device. It will help you track down where the voltage drop is. It's possible it's being fed a figure by the PCM, which very well could be a weighted average. It could also be unaffected by the voltage drop with the bass hit.

Big questions are whether or not it is affecting the whole car, and just not telling you, or if it is only affecting certain systems.

Also, do some probing around to check for loose/corroded major live and ground wires.

[nos4blood70]

This is normal and to be expected. You need to invest in a capacitor.

[JEFFSSSEI]

I second Nos4Blood70's comment, classic sign of needing a capacitor.

[Sether]

This is normal and to be expected. You need to invest in a capacitor.

Have tried capacitors, didnt work, probably not big enough for what I needed. Was thinking about just getting a second car battery for the amp and sub. But the single car battery should be able to power that thing.

[J Wikoff]

Capacitors have worked for me with similar sized components.

[Sether]

Capacitors have worked for me with similar sized components.

Ok any suggestions then? How many farads?

[J Wikoff]

1 farad. I had a RF brand cap for several years. It died. I got another, which, I think is the same brand.

[ddalder]

So, how loud are you playing this thing???

[Sether]

So, how loud are you playing this thing???

Uhhh...Decently loud, but not loud enough to hurt my ears XD I mean I've got a amp capable of 1300 watts and a 1200 peak watt subwoofer that is wired to have the least resistance possible so its pulling 1200 watts easily.

I will look for a RF cap but last time i looked into them they were like 60-70$ which is more then i wanted to spend back then.

[ddalder]

Hmmmm. Well, I was going to post another comment but I think it's more prudent to just keep it to myself.

[Sether]

Hmmmm. Well, I was going to post another comment but I think it's more prudent to just keep it to myself.

[redfury]

another Battery is going to cost you that much and then some. A sealed battery that has the reserve capacity you need to pull double duty as a buffer for the amp and the car is going to run you about $120 or more. Buy a decent Cap, take the strain off the alternator and battery. I'm running a 1200 JBL amp and a 12" Pioneer @4ohms and haven't had any problems, but I also have my amp tuned lower than the max rating and I generally don't crank it up much, so the load on my system is lower ( and I'm running a smaller sealed battery I bought from the junkyard.

[nos4blood70]

To be honest, even my little 300 watt RMS 10 inch sub will dim my lights if have a song with deep notes playing. Especially if there is already a decent load on the system from brake lights or the climate control.

First thing is first though, max wattage doesn't matter. Look up what your amp and sub are capable of in RMS wattage.

[Sether]

To be honest, even my little 300 watt RMS 10 inch sub will dim my lights if have a song with deep notes playing. Especially if there is already a decent load on the system from brake lights or the climate control.

First thing is first though, max wattage doesn't matter. Look up what your amp and sub are capable of in RMS wattage.

Dang, Im surprised that dims your lights, never had trouble with dimming until i had it loud on both my honda and my bonnie. The only reason I mentioned the peak power is because I have it wired to 1 ohm so its real RMS is going to be much higher, especially when the 600 RMS rating is for a 4ohm wiring.
So the max in this situation does matter.

[bmnicks48]

What type of capacitors have you tried? That should work - if not your only option is to get another battery which is going to be expensive and annoying.

[Sether]

What type of capacitors have you tried? That should work - if not your only option is to get another battery which is going to be expensive and annoying.

It was a *shoot* brand, BOSS audio. At the time i didnt have a full time job and didnt want to spend what a good one costs and tried it in my honda and it did not help because the brand is awful and I should of known better. Infact I should of known better when posting that reply months ago when I said I tried one. I Will invest In a Fosgate cap at some point. Just waiting till I get the motivation to do it or when the dimming lights annoy me enough to break down and buy one. Hasent been dimming recently through!