# Lights dimm after Big 3 Upgrade



## jcof88 (Mar 26, 2013)

Hey guys had a quick question, I have 2 kickers running on a 1600 watt rms amp and I did the Big 3 Upgrade, Added 0 Gauge to the power wire from the alternator, Added 0 Gauge from battery to transmission ground. then to Chassis ground. Its a new battery I just got from the Nissan Dealership. I think its a 130 or 140 amp stock alternator. Should they still be dimming after I did the big 3 upgrade because a lot of people say their dimming lights go away after doing the Big 3 Upgrade but mine didn't. Thanks for any help


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## Beckerson1 (Jul 3, 2012)

Well could be a couple things. Do some of the easier checks first.

1) Make sure your grounding points are clean of any paint. Also check and make sure all connections are tight (be it at the amp, up front, ect...)

2) make sure gains are set correctly.

3) if you can give the battery a good charge overnight. Generally for storage purposes they are only around % 80.

Now agm batteries do tend to supply burst current better then non agm lead acid batteries. Usually it's a good idea to go agm. But it's no reason to go out and get agm since you already have a new battery. Also depends on the size of your battery.

Do those checks and report back. Also I see you used 0 Guage for the big 3. I assume you also have 0 run back to the amp?

Worst case scenario is you need to grab another battery or two.


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## LaserSVT (Feb 1, 2009)

My truck with a 180 amp alt, the big three wire upgrade and only a 500w amp would do that at night if the AC was on max. Every bass note and it would dim. Voltage only dropped a small bit but the alt regulator takes a second to catch up. Swapped from a oreillys new battery to a new Motorcraft battery and the issue went away.


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## captainobvious (Mar 11, 2006)

Were they dimming before the "big three upgrade"? You have to understand that when your vehicle is started, your system is puling power from the alternator (as is the rest of the cars electrical system). The "big three" is not going to solve a lack of output or a faulty alternator. You may just be taxing the stock alternator too much, or it may be on the way out the door and need replacement. You may want to have the alternator checked out at your local autozone/similar store.


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## ATOMICTECH62 (Jan 24, 2009)

The big 3 has nothing to do with it.
If you truly are getting 1600 watts from the amp then that means you are pulling about 200 amps of current when you add in the current draw of the vehicle's electrical's needs.
So you have completely taxed the alternator of all its current and you are pulling the excess from the battery.
If you put a volt meter on the battery with the system cranked you will probably notice it reading min/max from 14.4 to 11 volts or so.
Going from 14.4 to 11 volts will be a 40% decrease in output with unregulated things like headlights.A 50 watt headlight will only produce about 30 watts at 11 volts and will cause noticeable dimming at night.


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## T3mpest (Dec 25, 2005)

yeah a little dimming is pretty normal, it's always good to get a voltage meter in there and see how bad the drop actually is, as long as your staying over 12volts your not taxing anything too hard in most cases. 1600 watts RMS is pretty serious power for any stock alt and some dimming at full tilt should be expected.


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## Lou Frasier2 (Jul 17, 2012)

T3mpest said:


> yeah a little dimming is pretty normal, it's always good to get a voltage meter in there and see how bad the drop actually is, as long as your staying over 12volts your not taxing anything too hard in most cases. 1600 watts RMS is pretty serious power for any stock alt and some dimming at full tilt should be expected.


how about with a second battery? i have my power bass xta 5000 running at 2ohms and my ppi p900.4 running at 2ohms and another small amp at 4ohms,front stage all hooked up to the front battery and xta hooked up to near battery for my subs and have never seen a light dim,big 3 done in o gauge


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## sirbOOm (Jan 24, 2013)

Probably should put 9/0 gauge wire in


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## jcof88 (Mar 26, 2013)

Beckerson1 said:


> Well could be a couple things. Do some of the easier checks first.
> 
> 1) Make sure your grounding points are clean of any paint. Also check and make sure all connections are tight (be it at the amp, up front, ect...)
> 
> ...


1) All points are solid and tight, My only concern is the ground I have for my amp, The actual point is good its under a seat belt mount in the back seat I took a grinder to the pint on the car and the seat belt bracket to make sure its getting a great connection but I don't have a terminal on the ground I just have the wire spread out on it. 

2) gains are all good, I used a Multimeter and a O-Scope

3)Charged battery but the charger said it was good, Still Dimming tho.




captainobvious said:


> Were they dimming before the "big three upgrade"? You have to understand that when your vehicle is started, your system is puling power from the alternator (as is the rest of the cars electrical system). The "big three" is not going to solve a lack of output or a faulty alternator. You may just be taxing the stock alternator too much, or it may be on the way out the door and need replacement. You may want to have the alternator checked out at your local autozone/similar store.


Got the Alternator checked out, They said it was charging normal and is in good shape



T3mpest said:


> yeah a little dimming is pretty normal, it's always good to get a voltage meter in there and see how bad the drop actually is, as long as your staying over 12volts your not taxing anything too hard in most cases. 1600 watts RMS is pretty serious power for any stock alt and some dimming at full tilt should be expected.


Its staying around 12.5. 

So I am guessing I have to upgrade to a High Output Alternator because I plan on running 2 JL Audio 12w7 in the near future with 2 JL Audio Slash V3 12000 Watt but for now I am staying with the kickers until I can get them, I just don't want to pay $600 for a damn 270 amp alternator that's just crazy expensive. Also I heard hooking up a 2nd or 3rd batter is only good if you plan on playing my system with the car off and no use when the car is on and puts strain on the alternator to keep the batteries charged is this true...Thanks


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## Sine Swept (Sep 3, 2010)

Next step - Dedicated ground wire from Front body ground to rear distro block to amps. HID's, just saying.


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## Beckerson1 (Jul 3, 2012)

jcof88 said:


> 1) All points are solid and tight, My only concern is the ground I have for my amp, The actual point is good its under a seat belt mount in the back seat I took a grinder to the pint on the car and the seat belt bracket to make sure its getting a great connection but I don't have a terminal on the ground I just have the wire spread out on it.
> 
> 2) gains are all good, I used a Multimeter and a O-Scope
> 
> ...


Lol if your wanting to push 12k your going to need alts (and I mean multiples). Adding batteries can help stabilize your voltage but does introduce stress on the alt. Your adding capacity to the system. Instead of say 130aH the system would see 260aH.

Takes longer to charge which causes the alt to work longer, not harder. Adding batteries is a temporary patch. 

If I were you and seeing your future plans I would suck it up and get the alt. It's a big investment I know but you will benefit down the road.


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## jcof88 (Mar 26, 2013)

LOL sorry I didn't mean 12k, I meant to say 1200 not 12000 wow that would be a lot of power, So all in all when its all said in done I will have (2) 1200 amps = 2400 watts pushing (2) 1000 Watt W7 Subs Sorry for the mix up


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## kyheng (Jan 31, 2007)

Consider upgrading your power cable from battery to fuse box also.


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## minbari (Mar 3, 2011)

Lou Frasier2 said:


> how about with a second battery? i have my power bass xta 5000 running at 2ohms and my ppi p900.4 running at 2ohms and another small amp at 4ohms,front stage all hooked up to the front battery and xta hooked up to near battery for my subs and have never seen a light dim,big 3 done in o gauge


an extra battery will not solve the dimming issue if your alternator is not able to supply ALL the current. 

battery = 12.5 volts
alternator = 14.4 volts.

If you pull more current than the alternator can supply instantaneously it will pull down to battery voltage and you will see a dimming of lights. doesnt matter how many batteries you use.


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## Negolien (May 17, 2010)

I run over 14 volts always with my stock 110 alt and big three on a standard battery. As for an alt running 2400 would mean you'd need around a 300 amp alt correct?


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## jcof88 (Mar 26, 2013)

Negolien said:


> I run over 14 volts always with my stock 110 alt and big three on a standard battery. As for an alt running 2400 would mean you'd need around a 300 amp alt correct?


The only alt I can find for my car is 270 amps, Would this be enough ?


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## Negolien (May 17, 2010)

That would push around 2000 good including car electrical maybe someone else could chime in more it's pretty close though. Have you tried Singer and Mechman?


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## jcof88 (Mar 26, 2013)

Negolien said:


> That would push around 2000 good including car electrical maybe someone else could chime in more it's pretty close though. Have you tried Singer and Mechman?


Singer has not got back to me yet, and Mechman has only a 270 amp

but from what I understand and correct me if I am wrong I really know nothing about it just from reading all over the internet, If I take what my amp runs RMS 1600 and / by 14v from the alternator I would get 114 and that would be the size on alternator plus 100 for the car its self so about 214 amp alternator from what I have read, and thanks for all your help


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## Negolien (May 17, 2010)

For 1600 yes but for 2400 you would need a larger alt. I think. Not sure what math they use. I just read a post the other day where someone said they had a 1600 watt and it was a 200 amp alt I think. So I divided the 2400 using the same math. if it takes 100 amp alt to run 800 rms then 100 x 3 = 2400


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## qwertydude (Dec 22, 2008)

The alternator is being taxed beyond it's limit. You'll always get dimming at that point especially when people never consider that alternators don't make their maximum power at idle which is when most people notice the dimming.

Easy solution for this is a second AGM battery AND build a current limiting charge circuit/isolator for the battery. Limit the maximum charge rate to about 30 amps or so and you'll never see dimming. A decent AGM battery can supply the burst current needed for bass peaks and charge during the lulls in music or when you're not at max volume unless you make a habit of driving around playing test tones at maximum volume.

So unless you're either willing to install a true high output low RPM alternator if there even is one available for your car, you either live with the dimming or install the second battery and it MUST have a current limiter or you'll still get dimming. Also you have to live with the fact your amps will pretty much only be running 12 volts. But it will solve the dimming problem and prevent high current peaks from wrecking your alternator long term.


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## cubdenno (Nov 10, 2007)

What car and year?

Did you take a DMM and with the car running and revved to about 2000 rpm, with your music playing, see what the voltage drop is? Or did you just check with car off? I didn't see how you took the measurement.

Unless your positive connection is old and corroded or you add a high output alternator, adding a larger gauge wire from the alternator positive to the battery positive is usually useless. The factory wiring is correctly gauged for the output of the alternator. Adding to it does not gain anything. Just letting you know.

Like mentioned previously, my first guess is that the voltage regulator is just slow to react. This is very common. My question regarding finding the voltage drop while car running revved to 2000 rpm should help either confirm or rule out the regulator as the issue.

What's the main type of music you listen to and volume. My reasoning is that if you are playing a lot of bass heavy content music, you may want to buy a battery tender and plug it in at night to top off the battery. It will help.


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## jcof88 (Mar 26, 2013)

so If I did the 2nd battery I wouldn't have to put in a new alternator ? 

someone told me 2nd battery don't do anything unless your running your car is off. 

I would like to in the future get a bigger alt when I decide to upgrade to the (2) 12W7 and (2) 1200 watts amps.


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## jcof88 (Mar 26, 2013)

cubdenno said:


> What car and year?
> 
> Did you take a DMM and with the car running and revved to about 2000 rpm, with your music playing, see what the voltage drop is? Or did you just check with car off? I didn't see how you took the measurement.
> 
> ...


Its a 2010 Nissan Maxima S 3.5L, I will recheck the voltage when I get home I am heading off to work now, I did check it with it on and at idle with my music up alittle I was getting around 12.5 to 12.9 v. But I will recheck after I get home


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## Airforceyooper (Sep 22, 2005)

Make sure when you're comparing these alternators you don't just look at peak output. Ask about their output at idle. I'd buy the alternator that has the most output at idle, not the most output at peak.


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## cubdenno (Nov 10, 2007)

jcof88 said:


> Its a 2010 Nissan Maxima S 3.5L, I will recheck the voltage when I get home I am heading off to work now, I did check it with it on and at idle with my music up alittle I was getting around 12.5 to 12.9 v. But I will recheck after I get home


Oy.

Save your dough and get the new alternator. 

Extra batteries give you more reserve. But batteries fully charged read on average at max voltage around 12.6 volts and fall off from there. So if you have the car running and the voltage is at 14 volts and a bass note hits and the voltage drops to 13 volts you will still see the dimming. Extra batteries won't help that. An extra battery will help if you upgrade to bigger amplifiers.


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## qwertydude (Dec 22, 2008)

cubdenno said:


> Oy.
> 
> Save your dough and get the new alternator.
> 
> Extra batteries give you more reserve. But batteries fully charged read on average at max voltage around 12.6 volts and fall off from there. So if you have the car running and the voltage is at 14 volts and a bass note hits and the voltage drops to 13 volts you will still see the dimming. Extra batteries won't help that. An extra battery will help if you upgrade to bigger amplifiers.


That's why I said if you want to prevent the dimming you have to put a charge rate limiter. A simple one is just a bunch of paralleled halogen bulbs. This limits the peak current going to the rear battery so you don't get dimming, the rear battery will provide the rest of the burst current. If you have a decent AGM battery it shouldn't dip below 11.75 volts even at full tilt with a 2000 watt amplifier.

And before anyone says his amp will burn up from running low volts, unless you have amps that burn up when playing with the engine off, it's not gonna happen. Limiting the maximum current going to the rear battery is the easiest way to prevent dimming if a high output alternator is out of the question. Which it usually is when people find out you can't just easily get a drop in high output low rpm alternator for nearly any vehicle except work trucks.


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## jcof88 (Mar 26, 2013)

qwertydude said:


> That's why I said if you want to prevent the dimming you have to put a charge rate limiter. A simple one is just a bunch of paralleled halogen bulbs. This limits the peak current going to the rear battery so you don't get dimming, the rear battery will provide the rest of the burst current. If you have a decent AGM battery it shouldn't dip below 11.75 volts even at full tilt with a 2000 watt amplifier.
> 
> And before anyone says his amp will burn up from running low volts, unless you have amps that burn up when playing with the engine off, it's not gonna happen. Limiting the maximum current going to the rear battery is the easiest way to prevent dimming if a high output alternator is out of the question. Which it usually is when people find out you can't just easily get a drop in high output low rpm alternator for nearly any vehicle except work trucks.


Ok I will probly try this first just because its cheaper lol start small and work up right 

Should I replace my Stock Nissan Battery with a AGM Battery also or keep it and add the AGM to the back ?

What Color should I Get, Yellow, Red or Blue Top. 

Also I have no idea on how to build a charge rate limiter. 

Thanks 

Also I will recheck the volts on the battery with the music up in the morning its to late to do it now lol 

I am using a DMM to test it, Most of the time I listen to Rock, but sometimes Rap but not very often.


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## qwertydude (Dec 22, 2008)

Ideally you'd have two identical AGM batteries. It's the easiest way to set it up since you don't know how to build and design a current limited charge rate limiter.

Don't get anything Optima, they're junk now. Get a Diehard Platinum AGM. You can easily get two for less than you'd pay for an Optima anything and they'll last longer and perform better than the Optima's.

G4 Ceramic Socket with 6 Inch Leads for High Temp Applications

Buy a bunch of those, like say 5. And 5 x 100w G4 bulbs.

Osram Sylvania FCR 64625 HLX 100w 12v Halogen light Bulb - 54248_13 for $3.15

You simply parallel all the sockets and install them inline with the positive lead before the second battery. You'll need to make a little metal box and mount them inside to make this work, you don't want hot light bulbs hanging loose. Then you experiment with different amounts of bulbs to see which one allows the most power without letting your headlight dim. Start with all 5 in and subtract them one at a time until you don't get dimming. The light bulbs essentially conduct like normal wires at low currents to charge the battery but at high current demands they heat up and will limit the absolute maximum current to whatever the light bulbs maximum wattage is due to their positive temperature coefficient of resistance. Easy dumb current limiter, and works quite well too.

Also when doing this the charge lead going to the second battery doesn't have to be huge, because the current is limited, an 8 gauge lead to the back will work just fine. You'll still need a 4 gauge to the amps from the rear battery.


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## jcof88 (Mar 26, 2013)

qwertydude said:


> Ideally you'd have two identical AGM batteries. It's the easiest way to set it up since you don't know how to build and design a current limited charge rate limiter.
> 
> Don't get anything Optima, they're junk now. Get a Diehard Platinum AGM. You can easily get two for less than you'd pay for an Optima anything and they'll last longer and perform better than the Optima's.
> 
> ...


ok cool thanks ill give it a try would be nice if this works without spending 600 on an alt. lol also when I upgrade to the 2 Jl audio amps hopefully it don't dim either, What about getting a capacitor would that help any. I have all 0 gauge in the trunk so ill just tap into it. 

Just one more thing will this have any effect on my amp power wise, Sorry I am new to all this and don't know


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## jcof88 (Mar 26, 2013)

ok I rechecked my voltage and heres what I got.

11.7v when car is off
13.7 When car is on
then after I few mins it will drop down to 12.7 with everything off

12.7 with Headlights on, AC, and radio on, subs off

I tested with some hard hitting rap, It will drop to 11.8V and bounces back to 12.4 and bounces back and forth.


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## qwertydude (Dec 22, 2008)

With the car running rev it to 2000 then 3000 rpm and test the voltage with your accesories and headlights on air conditioner blowing max. Should be about 13.8 to 14.4 volts. You see at idle you're just breaking even with headlights on. With a rewound alternator you'll drain your battery unless you get an overdrive pulley and belt that fits it.

If your sub is pulling the voltage down to 11.8 volts you're running purely on battery power by then. In that case the current limited second battery will run your amp at the same power level as your current setup and will also strain your alternator much less.


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## altec (May 28, 2011)

if your voltage is 11.7 with everything off then your battery needs checking


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## qwertydude (Dec 22, 2008)

The battery is resting at 11.7 is relatively normal. It is a little on thelow side but if he's regularly dimming ihis headlights with his suwoofer, that's not unexpected.


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