# Sigh... Big 3 done, lights still dim, what now?



## darcness (Mar 13, 2008)

Well as the title says, I've done my big 3 upgrade and my lights are still dimming. I just don't get it. My system isn't all that intensive. A class A/B amp @ 230w and a class D @ 500w and I'm still getting dim. This is driving on the e-way about 80 and the dim is very noticeable.

It wouldn't be THAT big of a deal, but it must be causing voltage drops to substantial levels because my CarPC inverter is kicking into protect mode. This is HIGHLY annoying because then I have to turn off the inverter, turn it back on, and then reboot the PC. 

I did my big 3 with 4 gauge, thinking that 0/1 gauge would be overkill with the mild setup I have. Now I'm starting to wonder if this was a mistake. However, I don't want to go out and spend a bunch more money on cable and then not have it work again. I did the big 3 properly. Sanded AND filed all ground points, used terminal rings, and upgraded/new battery posts. 

I don't know what to do next. I'm thinking the battery may be the weakest link at this point. It's just a regular car battery, and I'm fairly certain it's older. It starts my car fine, but I think it may not be enough for the audio system. Is there any way to test the battery? Also, would getting a new battery be my best bet?

Alternatively I thought a HO alternator would be a good bet. However, this is obviously going to cost me more money. I'd rather rule out the battery first. 

I know all the wiring is good as I just put re-worked it all. I have 4 gauge going from my battery 12v+ to my distro block. Then 3 8 gauge outputs to my 2 amps and my inverter (longest one being ~ 2ft). The ground wire (also 4 gauge) is about a 2 foot run from my chassis (ground and filed, then bolted) to my distro block. Then 3 8 gauge outputs to the above loads (again ~ 2ft for the longest run). I double checked all connections and they are all sound. Also, the wire is brand new. Only thing I can think that may be causing an issue with the wiring is the 8 gauge to the mono block, 500w amp. 

Please help. This whole thing is making me crazy.


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## cheesehead (Mar 20, 2007)

darcness said:


> Well as the title says, I've done my big 3 upgrade and my lights are still dimming. I just don't get it. My system isn't all that intensive. A class A/B amp @ 230w and a class D @ 500w and I'm still getting dim. This is driving on the e-way about 80 and the dim is very noticeable.
> 
> It wouldn't be THAT big of a deal, but it must be causing voltage drops to substantial levels because my CarPC inverter is kicking into protect mode. This is HIGHLY annoying because then I have to turn off the inverter, turn it back on, and then reboot the PC.
> 
> ...


Well here are my thoughts for what there worth...........

I am running more power than you on my stock electrical system without dimming. I am also running 4 gauge power to distro block and then 8 gauge to amps. My guess to what is causing your problems either lies in the battery or the alternator. Do you have a volt meter on your vehicle? Have you noticed any changes?

Here is what I would do. Take your vehicle to Auto zone/walmart auto/ Advanced auto ect. and have your battery checked for free. See what they say. It may be the battery is not able to sustain the surge that your system is giving it. Maybe a larger battery would do the trick!


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## darcness (Mar 13, 2008)

This too is what I'm thinking. I don't have a voltage meter on my car, but I do have access to a nice DMM from work. I could use this to test the battery. Just don't know exactly what to look for.

If it is the battery, I'll likely be replacing the starter battery with a Kinetic. I was looking at the HC800 as an "all-in-one" battery. Seems to be fairly powerful and priced nice on Ebay. I just don't want to go spending $100+ on a battery if it's not the problem.


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## cheesehead (Mar 20, 2007)

Well wait a couple of hours for the professionals to wake up. Someone will be able to help you with some more technical help.

As for me....I am just running stock electrical, 4g - 8g wiring, and the biggest cca battery walmart had. I have yet to have any dimming issues. 

So my guess for you is either the battery is weak/not big enough or the alternator is not charging like it should.

G/L


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## t3sn4f2 (Jan 3, 2007)

Your problem should not be wiring, bad wiring will restrict the amount of current your amps can pull which would help with dimming not make it worse. I say its your battery, no reason that the reserve capacity of any new battery can not handle the amount of current _your_ system pulls. Especially with the help of a stock alternator at highway speeds. 

It seems your alternator can not keep up even at highway speed and is revealing your battery problems. This doesn't mean you need to upgrade to a high output model though, since a high output model will still need help from a good functional battery at anything other then higher RPMs.


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## chad (Jun 30, 2005)

My dimming went away with a good battery, and this is also dimming that occurred with the AC clutch/fan kicking on at the same time, the EPS (Electric Power Steering) while parallel parking, and the stereo, all gone. No changes to the wiring aroud that time.


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## 60ndown (Feb 8, 2007)

i think almost any major store will take a battery back within a week, go buy a nice battery, try it, if you still dim, take the battery back and tell us.if the dimming goes away, come and tell us


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## tommyd (Nov 7, 2007)

I am in the same situation as you right now. Same electrical runs as you as well. Still have dimming b/c of a crap napa battery. Just for ****s I hooked my friends optima up. Dimming solved. Now I just gotta buy one.


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## chad (Jun 30, 2005)

What kind of car is it and what size battery?


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## durwood (Mar 7, 2007)

First, what are your PC specs that you require an inverter? Is it possible to buy a good DC-DC solution or are you too cheap or too powerful to use one the options available?

Second, are you sure it's the voltage drop and not the voltage spike sending the inverter into protect?

Third, how old is the battery and have you had it checked out with a good load test?


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## chad (Jun 30, 2005)

tommyd said:


> I am in the same situation as you right now. Same electrical runs as you as well. Still have dimming b/c of a crap napa battery. Just for ****s I hooked my friends optima up. Dimming solved. Now I just gotta buy one.


**** man, I had a spare Duralast gold I popped in the civic for ****s and grins just to test inthe driveway, it was too large to fit and drive with.... But/.... dimming solved 

When I comment though yall need to keep in mind that I don't have a flamethrower equiv of amplifier power


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## darcness (Mar 13, 2008)

durwood said:


> First, what are your PC specs that you require an inverter? Is it possible to buy a good DC-DC solution or are you too cheap or too powerful to use one the options available?
> 
> Second, are you sure it's the voltage drop and not the voltage spike sending the inverter into protect?
> 
> Third, how old is the battery and have you had it checked out with a good load test?


Already ordered an M2-ATX (DC-DC) PSU last night. 

Sounds good about the battery. I'll pick one up this week when I get paid. Thanks for the input guys!


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## Whiterabbit (May 26, 2006)

darcness said:


> Well as the title says, I've done my big 3 upgrade and my lights are still dimming. I just don't get it.


http://www.betteraudio.com/geolemon/newmain/battcapalt/

Start halfway down.


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## tcguy85 (Oct 29, 2007)

Whiterabbit said:


> http://www.betteraudio.com/geolemon/newmain/battcapalt/
> 
> Start halfway down.


nice.


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## darcness (Mar 13, 2008)

Hrmm, now this article is completely contradicting what I thought. This guy is saying to use a capacitor at this point. Just stirring the pot. I think I'll try the battery first. I can always take it back as suggested, if it doesn't fix the issue.


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## Whiterabbit (May 26, 2006)

sheeple are very quick to throw around buzzwords like "bandaid" when it is popular to bash gear.

Chances are you have a local friend with a cap or two you can borrow for a test. I know a guy up the road a bit who has three or four, I've got two in the garage. I'd be using it too, if I had the real estate. And if I had dimming problems you better believe I'd be MAKING the room if a test proved beneficial.

It's been awhile since I've read the article, but also remember if not mentioned there, the ability of a cap to prevent negative ripple is pretty limited. If you see light dimming on bass test tone music, theres nothing you can do about the dimming. If it's on something less harsh.... maybe....

Something else to consider: The yellowtop idles at what, 13.4 volts? So if your cheap old battery rests at 12.8, and the drop from 14.2 on the alternator is resulting in light dimming, buying a new battery MAY BE the only needed solution. Dropping .8 volts wont dim the lights as much as 1.2, right?

"""But talk about a "bandaid!" you arent solving the problem, you are just using a battery with a larger idle voltage to reduce the drop!"""

the rhetoric sounds familiar, doesnt it?  We can go on calling anything a bandaid if we want. The best example was when Vestax called a signal processor a bandaid for a bad install. He's right, isnt he? And yet noone here argues about how processors are the most evil gimmick around, etc.

bashing a cap is IMO out of style (though plenty are doing it).

It's a damn cheap test when you can ebay or craigslist them for less than 20 bucks.


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## vactor (Oct 27, 2005)

try a capacitor. i know things have been said that they don't work, but, try to borrow a half or one farad cap with low ESR and just plug it in your system. i'd bet dollars to donuts (only a dozen please) that you notice that your dimming problem gets drastically better or disappears altogether. and heck, 1 farad caps are cheap!!


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## chad (Jun 30, 2005)

1 farad caps that are of the quality required and are actually one farad are NOT cheap


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