Lights STILL dimming even using a 5 farad cap!!

[LazerBlueP5]

I noticed tonight I still get a minor headlight dim when the bass hits. I figured having a 5 farad cap (alumapro cap 5) would alleviate this?! Should it have?!
I'm running two amps a 300/2 and a 500/1.

 

[LazerBlueP5]

No it's 5 full Farads, trust me. lol It's like buying 5 of those 1 Farad can style capacitors but is the size of a small amp.

 

[sttl013]

I've been fighting this battle for 10 years, and made some enemies out of car audio salespeople for saying this:

There are 2 different reasons that the cap didn't help your dimming problem.
First, capacitors aren't designed to stop lights from dimming. They're designed to aid in keeping constant power flowing to any device needing an immediate burst of power, in this case your amplifier. When the bass hits, the amps requires more power to operate, and if the electrical system can't supply the juice needed as quickly as it's wanted, a cap will help provide it. One of the possible pleasant side effects of this is that other electrical devices don't get robbed of the power necessary to run them properly (your dimming headlights). Factors determining this are: 1) capabilities of your existing electrical system [80 amp alternator, anyone?] regardless of your battery; 2) current draw of your amplifiers; and 3) size and quality of the capacitor [we'll cover this one in a minute]

So, we start with the electrical system. Like I said, an 80 amp alternator is the minimum that this car can get away with, having all the power options that it does. The battery, to a point, is irrelevant since it mostly is there to power the car when the ignition is off. I've never seen a battery that performed as good on it's own as it did with an alternator behind it. Don't believe me? Find the person with the most expensive battery you can find, and measure it's voltage with the car off, then with the engine running. Guaranteed it's going to be higher with the car on. So, once our current draw exceeds 80 amps, it's all up to the battery, and chances are, it's going to drop.

1stMP3 can probably fill us in on how much current those amps actually use. I don't have the slightest idea. Just add that amount to the current draw of the ignition system, the other electrical accessories in use, including the headlights, parking lights, taillights, neon tubes, etc. and you see where we're going.

As far as the size and quality of the capacitor, I read the spec sheet for a Pheonix Gold cap similar to yours, and was pretty pissed to see how they came up with the figure of 15 farads. I'll look for it to show you, but it was similar to how some audio companies rate amplifier power at max. rating with 10% distortion at 1KHz. Not an accurate measurement. I highly doubt that your cap is capable of what 5 can-style caps would do, although I would still hesitate to buy a bunch of caps to stop my lights from dimming.


Wow, I really know how to over-analyze, sheeeze! Hope this plethora of info gives you some insight into your issues.

 

[sttl013]

By the way, I saw the pics of the install. Awesome job, I hope you get the nics inside fixed up (I didn't see them in the pics).

 

[MikeBlueP5]

Just get HID's. Mine did it too even with my stinger cap. its 1 farad and I was only running one amp at the time. The HID's only use like 35 watts, and not many volts. They dont blink.
Mike

 

[Rider69]

When they did the install, did they run new, larger wires from the battery to the alternator and chassis. I found that just by running a 1/0 gauge from battery to chassis helps alleviate alot of the dimming. As a matter of fact, I have no dimming whatsoever right now.

 

[1sty]

I am not suprised that the lights still dim slightly. The JL amp is power hungry but puts out like a champ. If your lights aren't really dimming then the 5 farad cap is doing its job.

For anyone that wants the specs on the JL amps and the 5 farad cap, all can be found on www.carsound.com, review section.

 

[blynzoo]

I was actually going to ask, 1st, was it you who replaced the alternator?
To restate what sttl said so well, no matter how good your conductivity, if your original power source is insufficient, it wont make a bit of difference. Kind of like running a 4 hp generator through those high-voltage power lines all over the country and expecting everyone to get power without dimming.

I am stereo ignorant, but from a physics standpoint I'd say the initial source (alternator) is the culprit. And with the alternator, most cats who go big-power use supplementary batteries, charged during driving (like the stock one) that the stereo can pull power from when that one ass-shakin' cootchie flippin' (sorry, had to use imagery here for my own pleasure) bass note hits. However, before someone flames me, for most stereo applications, I do not believe supplementary batteries are necessary if the alternator is doing a good job of providing juice to the battery.

Hey, speaking of the 4hp generator, why not just put one of those in the car, route the exhaust through the stock pipes, and do a "how to" page on it?

Orrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr not.
PM 1st and see what he has to say.

 

[1sty]

I did replace my alternator.
Even a larger alternator can't stop the dimming but once again it helps. Basicly the alternator needs a breif second to realize the new loads and react to it. Hell my alternator cranks at over 15 volts and can do an idle current of over 100 amps but will still dim when the 1000/1 hits quickly, but it does recover.

 

[Gyre]

You could maybe put a cap on your headlights

 

[1sty]

Better yet a seperate battery.

 

[LazerBlueP5]

So it's drawing from my battery. Does this mean it's going to croak in a few months.
Now beings I DO have 5 Farads and my lights still dim DOES this mean the cap isn't installed correctly?!

 

[1sty]

It does not draw from the battery!
If the car is running then it only draws from the alternator. However a seperate battery for just the head lihgt, AMAZINGLY OVERKILL, would stop the dimming.
The cap is working fine. If youthink it may be bad have them disconnect it quickly to see the difference.

 

[dominoy2k1]

i have a 2000wattamp with 1.5 farad pushing 2 12in impps and the dimming is very minimal with everything on.......

 

[1sty]

What is the amps model number and manufacture?

 

[dominoy2k1]

well its a precision power amp need to go check model number.......it might be a 1400......... let me check when i get off work.............