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Best Options for Headlight Dimming, Big 3 Upgrade or Capacitor?

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Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
Printed Date: January 24, 2022 at 12:05 AM

Topic: Best Options for Headlight Dimming, Big 3 Upgrade or Capacitor?

Posted By: tidbit96
Subject: Best Options for Headlight Dimming, Big 3 Upgrade or Capacitor?
Date Posted: September 09, 2018 at 11:38 AM

i have a 2003 Lincoln TC, w/a Soundqubed HDS315-D2 1200RMS & an Orion cobalt 2500.1D 1ohm stable amp, which is what it's wired to. I only have 4ga100%OFC ran for pwr/gnd which Im sure you'll say is too low of ga. I actually know & agree on that fact, its just my financial circumstances left me unable to afford the luxuries of larger ga. Pwr/Grd. & I owned all the 4ga wire i ran. W/how pricey the 15+feet of 0/1ga OFC id need for my boat of a car I'll just stick it out w/what i got for now cuz i wont run that cheap cca crap only OFC in my setups.

   Anyway, my issue is when the heavy bass hits my headlights & even occasionally dash lights dim on the really big thumps. ive read up some on the big3 upgrade & have plenty extra 4ga OFC left to use if i decide to go that way(which after seeing my stock set up & realize that they're only 8ga at best, I imagine 4gaOFC would provide a much needed boost in efficient power supply.) However, i dont know a terrible amount about capacitors. obviously i know enough to understand what they do & realize adding 1 would probably be a certain solution to my problem, however i chat on a few different forums & Ive heard mixed opinions on the topic of capacitors. Now obviously I'm sure your thinking, "duh get a capacitor, you already said you know it would solve the problem!" But as I mentioned earlier, you must keep in mind my financial situation is just a few dollars above trading food stamps for spare speaker wire on the streets lol ok its not that bad but just wanted you to remember all the variables of the problem on the way to the solution. Basically I'm asking for opinions on weather or not yall believe I could get enough result from the big3 in order to save me the cash a new capacitor would set me back? ive priced capacitors & figured i can prolly splurge to $70-$80 tops on hopefully a half way reputable brand of capacitor if you believe this way to be my best choice. So also consider that as part of the equation, would I be able to find a capacitor, in that price range, decent enough to make it worth buying anyways? If they're anything like Amps, I've had too many costly lessons on the truth behind, "you get what you pay for" I started w/a BOSS A/B class amp, so as you might imagine, I've already received that expensive lesson straight to the family jewels! Lol so I'm looking for strong, yet price efficient choices plz.

i hope i included enough info for y'all to be able to give me a few thoughts on what route/routes I should choose in my attempt to solve this annoyance. if any1 has ?'s for me regarding my setup or if I left some crucial needed info out, plz feel free to enlighten my novice butt lol id be happy to help give you whatever info's needed if your willing to help me make, hopefully an affordable & effective decision. Thanks, everyone!

Tidbit stays deep in the T-Wat


Posted By: i am an idiot
Date Posted: September 09, 2018 at 12:52 PM
Not the capacitor.

Posted By: DYohn
Date Posted: September 17, 2018 at 7:43 PM
Upgrade the alternator and the big 3.


Posted By: tom.carlover
Date Posted: November 07, 2018 at 9:35 PM
Always high output alternator and Big 3. Only if your problem persists would I ever consider a capacitor.

Posted By: deaner_gs300
Date Posted: November 12, 2018 at 9:18 AM
The previous three answers should tell you what you need to know... I will throw my $0.02 in here too just to help drive it home though. I would say: Don't get a capacitor if all you can afford is $80-100 worth because they don't do much for you and you're much more likely to get cheap s#*t. One of the car audio channels on YouTube had a video of them where they had cut open two capacitors and the active material inside was minimal compared to one that cost about twice as much. I also think that they have their place in car audio but they get used way more than they need to and often for the wrong reason.

I don't know if this is just in Austin, TX or if they are running this special or one like it in all their stores but Wal-Mart has been running this special on car batteries for almost a year now where you can buy one of about ten different sized 12 volt car batteries for $48.XX and these are decent BRAND NEW batteries. I actually have bought two now. I have one on my work bench currently and I use it to test out electronics (briefly) but I really bought it to have an extra on hand in the event the old one in my car decides to fart out on me one day soon. I didn't want to pass up on the deal. In fact I'm thinking about going and buying at least one more and doing it like I would suggest you do here. Adding a second battery and putting an isolator on it so that it charges but it stays separated from the other battery when the car is not running and charging the system.
If your Wal-Mart has this deal then you can get the whole setup for under a hundred bucks depending on the amperage you're running. I think you can actually get the Stinger SGP38 80-AMP Battery Isolator and Relay for $15.88 with free shipping on Amazon right now. I'm guessing that with the issue you're having that this might be too small of an isolator relay but you smell what I'm stepping in anyway...… Just something to think about really, and I would certainly go that route before I gave any of those scheister's a dime for a crappy capacitor (not that they are all bad... just lots of them) Honestly I have a similar situation. I have a small voltage drop even after doing the big 3 and I think with these batteries so cheap it can't hurt and will likely make it all much more efficient.

Good luck!!

Alpine CDE172BT - Infinity PR6500CS 6.5's - Zapco ST2X SQ - SSA Evil-6.5's Mid-bass - Zapco ST2X SQ - Sundown SD3 12" D4 - VFL Comp 2K... 1995 Lexus GS300 - The Frankenstein build & it changes weekly.

Posted By: series vii
Date Posted: November 28, 2018 at 12:05 PM
Adding an additional battery(s) might be a short term fix but in the end you need to make more power aka HO alternator. Whats the point adding a batt or even a crap if you cant charge them? Even with an isolator you will need to charge the bat eventually. Good chance you will fry the alt you have by draining the batteries down far enough the Alt works full force trying to fix the lack of capacity it had before. Also adding cheap starting batteries is just going to cost you money. They are not made to do what you want in this situation.

Alternator, Big 3, correct wire size. If you spend a lot of time with the vehicle off, then look into deep cycle batteries.

Posted By: deaner_gs300
Date Posted: November 29, 2018 at 4:18 AM
Don't waste your time with an alternator if you don't need it. A little dip in your voltage causing your headlights to dim isn't cause for alternator upgrades unless you were already planning on doing this surgery. The isolator allows both batteries to charge when the car is running while separating them, keeping them from discharging or sharing their charge while sitting with the key off.

If you like changing alternators though, by all means change it. It's likely that it's not the last time you'll change it AND I'm hoping that YOUR local auto parts store carries those HO alternators because it's likely not the last time you'll end up changing it and that's a helluva time to have to worry about shipping the heart of your charging system to another state for warranty work.

I will say that a deep cycle battery will be a better bet for longevity but if you're honestly not throwing 2000 watts at the stereo with a constant 100 amps of power you don't necessarily need an alternator and I'd take 50 bucks worth of adequate amperage over $300 worth of deep cycle that is truly overkill for the system you're running.

Pick your battles. Replacing alternators is one of those battles I rather only face once if I can help it.

Alpine CDE172BT - Infinity PR6500CS 6.5's - Zapco ST2X SQ - SSA Evil-6.5's Mid-bass - Zapco ST2X SQ - Sundown SD3 12" D4 - VFL Comp 2K... 1995 Lexus GS300 - The Frankenstein build & it changes weekly.

Posted By: deaner_gs300
Date Posted: November 29, 2018 at 5:12 AM
And as far as the big 3, I'm assuming that it has already been done. Which is a bad assumption. Yes, first do "the big 3" by upgrading your charging system with better bigger gauge wire to your alternator as well as the chassis ground and the ground on your engine block.
You may in fact find that doing this kills much of your problems with dimming headlights without having to go any further. The alternator is a third step. Add a second battery because the alternator you have will charge both as long as you're not just sucking amperage like that fat beast sucking down Diet Coke with her triple stacked Big Mac breakfast.
I'm guessing series vii sits around in his front yard with his car stereo on and the motor off cruising for chicks because he's obviously not read any literature on how the charging system works. I don't know why my solution means charging two dead ass batteries over and over and over. In fact if you never let the starting battery get below 12 volts then starting and running your car is never a problem and that being the case then the other battery will also not have an issue.
Ask a shop that upgrades cars for cops and ambulances. Sure the alternator is a major player but that's after you get to that point. A second battery can be charged enough for your system using a stock alternator without even noticing a dip in voltage.

Alpine CDE172BT - Infinity PR6500CS 6.5's - Zapco ST2X SQ - SSA Evil-6.5's Mid-bass - Zapco ST2X SQ - Sundown SD3 12" D4 - VFL Comp 2K... 1995 Lexus GS300 - The Frankenstein build & it changes weekly.

Posted By: eguru
Date Posted: November 29, 2018 at 7:43 AM
Adding a second battery will not help the light dimming issue. The second battery is in the same category as the capacitor. It stores energy and releases it but at some point the energy must be put back in. Only the alternator can provide the energy - so if the alternator can't handle the load that is currently connected, it certainly won't be able to also recharge an additional battery (or a big capacitor).
Reducing power lost in cables and connectors is a good thing but don't expect miracles - the limiting factor is still the alternator.

If the OP can only splurge $80 on a fix to his 2000W sound system in his Lincoln, I guess we don't have a solution that will work for him.

Posted By: series vii
Date Posted: November 29, 2018 at 12:55 PM

"I'm guessing series vii sits around in his front yard with his car stereo on and the motor off cruising for chicks because he's obviously not read any literature on how the charging system works." Sorry Sport, I don't have much time cruising for chicks these days, I'm putting my 25 years experience as an Installer and Audio Eng. to use. Never bothered with the literature on charging systems, I just hung out for years with Ron Jones at Wrangler. Anyone living in Phx during the 90's knew Ron. " It's funny how many chuckle heads give out free advise based on well, whatever... it all comes down to physics and the right and wrong way to do things". Heard this a lot around there.

Sounds like you are scared of alternators, so then replacement isn't the right choice? I have replaced more undersized, over worked Alts by 10:1 compared to failures with HO models. HO Alts for that TC is maybe $100 more than stock and an hour tops to change out. I'll take a HO for reliability any day of the week.

Ex: Your Alt is rated @ 100 amps hot. The vehicle, lights, fuel pump elect, systems etc draw 65 amps. Now add a 100 amp draw to that electrical system aka monster amp. The alternator now must contend with a 165 amp demand. The Alt is now overloaded and must take what it can from the battery. The battery is now being depleted. The system voltage has now dropped. Sitting at a stop light, you pause the track, your Alt is now hotter than balls trying to replace what the amp sucked out. As that batt tries to recharge and a reduced load on the system, voltage should rise, however your batt isn't charging until the voltage reaches 13.9v or higher. You get out of the vehicle down the road and turn it off. Now the batt which never saw a sufficient charging voltage is now weak. Say you have an Iso and a second Batt, now both are undercharged. Add in any voltage drop between the two batteries through wire/iso/battery differences. The number two batt may be getting a volt less charging further reducing it's available charging voltage. Start the vehicle, the Alt is now having to run the vehicle again, charge the main battery that just supplied a huge amount of current to start the engine then add on the second batt that is now linked to the main. They were under charged before shutting down, wearing and tearing both batts. Some gain is made due to the Alt being cold and supplying some additional power until it heats up. Rinse and repeat day after day and see what gives out.

Same example, enter a 200 amp hot rated Alt. and do the math. Now the Alt has a fighting chance to not only charge the battery (s) but supply enough voltage for the rest of the systems. Battery longevity and Alt reliability return.

Posted By: series vii
Date Posted: November 29, 2018 at 1:13 PM
Some interesting reading on the subject:

Posted By: series vii
Date Posted: November 29, 2018 at 2:50 PM
More interesting reading on the subject:

Posted By: deaner_gs300
Date Posted: November 30, 2018 at 10:59 AM
series vii wrote:

Some interesting reading on the subject:

This guys should get paid for this website! I can't te3ll you the amount of times this site has been posted on different boards for a thousand different reason's.

I said First do the "Big 3" then go from there. I would not add a capacitor because for the same price you can buy a battery which DOES actually do something when a $60 is likely garbage.

Alpine CDE172BT - Infinity PR6500CS 6.5's - Zapco ST2X SQ - SSA Evil-6.5's Mid-bass - Zapco ST2X SQ - Sundown SD3 12" D4 - VFL Comp 2K... 1995 Lexus GS300 - The Frankenstein build & it changes weekly.

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