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View Full Version : Do I need a cap?


itsbmw
09-05-2008, 03:58 PM
I don't have the money for a new alternator but I do have the money for a capacitor. Last night I was in the parking lot waiting for my dad and I had the music on subs on and everything and I noticed my head lights were dimming, it wasnt a lot but still. I thought that maybe it was because the car had been idling(I never have this problem when I'm driving) and the lights stopped dimming after I ran it for a 5 seconds at 4k rpm(then a few minutes later they started dimming again but not as much). I was wondering If I need a capacitor or if I should save up for a HO alternator. Or do I even have anything to worry about..

YALEROYNOT
09-05-2008, 04:13 PM
a cap should not be used to fix that problem IMO. check your battery,wires, alt output, voltage regulator and connections amp wire size is important to. I have always used caps but for the purpose of giving the amps clean voltage. if you ever had a meter (multimeter) on a car you will notice the voltage jumps all over. this jumping is not good for sentive electronic equipment (amps, computers,etc). in a sence I use the cap as a voltage regulator. also amps are useally rated at X watts at 14.3 volts and people hook them up they think they are getting X amount of watts, they aren't at 12 volts this is another reason that I like to use a cap so that I can adjust the voltage to the amps for them to run there best. (this is the reason that I use them not saying that I am completlly right, but there are other reasons problelly that you are having a problem IMO)

sk8rsteve2004
09-05-2008, 04:14 PM
I would invest in a cap. That is something im going to get to whenever I can get a better amp for my subs. But I would also get the H.O. alt when you can afford that.

itsbmw
09-05-2008, 04:18 PM
ok. First Im going to see if anything happens if I do the big three, I just gotta buy the wire. if that doesnt help then I'll just save up for a HO alternator :p

YALEROYNOT
09-05-2008, 04:22 PM
ok. First Im going to see if anything happens if I do the big three, I just gotta buy the wire. if that doesnt help then I'll just save up for a HO alternator :p

go to auto zone and have them check the alt and battery (for free) save a lot of time and head ach .

itsbmw
09-05-2008, 04:24 PM
^^ok Ill have to do that this weekend thanks.

Ryan from Ohio
09-05-2008, 07:19 PM
Doing the big 3 should fix your problem. Just run 4 Ga wire.

itsbmw
09-05-2008, 09:37 PM
Doing the big 3 should fix your problem. Just run 4 Ga wire.

ok. great thanks ryan. the amp only pulls a max of 760w so I didnt thing this would be happening :p. But yeah my wiring under the hood sucks. Ill upgrade to 2 or 4 gauge. my wiring kit is 4 gauge so I might as well do 4.

Beholder88
09-06-2008, 08:46 AM
A capacitor still wouldn't be a bad thing to invest in. I had one with my old system. I had a Pioneer 760W Amp running two Pioneer 500w 12" subs. My lights dimmed all the time at idle, even with 2ga wiring and an HO alternator. I just took my alternator to a local shop and had it re-wound for higher output. Cost me $50 and it worked great. Went from I think 90a to 150a output @ 2000 RPM. Autozone will test it for free too, if you decide to go that route. After I added the CAP, no more dimming!

itsbmw
09-06-2008, 08:54 AM
A capacitor still wouldn't be a bad thing to invest in. I had one with my old system. I had a Pioneer 760W Amp running two Pioneer 500w 12" subs. My lights dimmed all the time at idle, even with 2ga wiring and an HO alternator. I just took my alternator to a local shop and had it re-wound for higher output. Cost me $50 and it worked great. Went from I think 90a to 150a output @ 2000 RPM. Autozone will test it for free too, if you decide to go that route. After I added the CAP, no more dimming!

Ok. awesome. Can the factory alt be rewound? or would just getting a new HO be the best?

Beholder88
09-06-2008, 08:56 AM
I'm not sure which would be the "best" option. If you want brand name stuff go with the new HO. I had my factory alt rewound, most alt or battery shops will do it for you. Sometimes the voltage regulator or some other stuff might need replaced too. It's usually cheaper to get one rebuilt anyways, rather than to get a new one.

Ryan from Ohio
09-06-2008, 09:44 AM
Doesnt matter if you have a 200 Amp alternator if you only have 10 Ga wire going from the Alt to battery and ground to batt, batt to engine... You can still only suck a small amount of amps thru it.

Reason the lights dim is your system is sucking enough power thats currently available via the small supply wire and causing the voltage to sag below the nominal 13.8 Volts. Thus you see a slight dim.

itsbmw
09-06-2008, 11:18 AM
Doesnt matter if you have a 200 Amp alternator if you only have 10 Ga wire going from the Alt to battery and ground to batt, batt to engine... You can still only suck a small amount of amps thru it.

Reason the lights dim is your system is sucking enough power thats currently available via the small supply wire and causing the voltage to sag below the nominal 13.8 Volts. Thus you see a slight dim.
That's what I thought. yeah the factory wire is small I was lookin at it and I was like wowwww. well im returning my street glow accent lights today so Ill have 100 dollars I should get some new wire or an Iphone(I can sell my blackjack for the other hundred) I dont know yet :p

deathwish666
09-06-2008, 12:16 PM
i just bought a cap off a friend for 20$...when i hook it up ill let you know how it goes

itsbmw
09-06-2008, 02:59 PM
^^ok cool. I'm going to murrays today to get new wipers(mine suck you can see better through the rain then after they wipe the window) I'll have them check my voltage and everything while I blast it