# Major voltage drop



## MyJeepGoesBoom (Jun 6, 2011)

I've got my 18 in and on 1/0 gauge and pushing about 1700w to it. Lights are dimming like crazy and voltage gauge fluctuates reallllyyyy bad. Would it be worth it to wire in my other h.o. battery near my amp or would it be too much more load on my alt?


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## envisionelec (Dec 14, 2005)

MyJeepGoesBoom said:


> I've got my 18 in and on 1/0 gauge and pushing about 1700w to it. Lights are dimming like crazy and voltage gauge fluctuates reallllyyyy bad. Would it be worth it to wire in my other h.o. battery near my amp or would it be too much more load on my alt?


Search the forum for "dimming lights". Please.


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## IceWaLL (May 30, 2005)

I think every car is different. IF your problem is capacity then another battery works wonders and I believe it usually helps to keep voltage at 12 volts or >

but if the alternator isn't up to the task or you need constant high voltage then only a HO alternator will do.

and of course having both is ideal (DUH)


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## kyheng (Jan 31, 2007)

Pushing the sub @1ohm load?


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## MyJeepGoesBoom (Jun 6, 2011)

Yeah its wired at 1 ohm.. problem?


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## cubdenno (Nov 10, 2007)

MyJeepGoesBoom said:


> Yeah its wired at 1 ohm.. problem?


Possibly. Though I am assuming the amp is rated as a "1 ohm" capable amp.

You say there is voltage drop. What are you seeing besides dimming lights. Have you measured the drop with a DMM?


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## MyJeepGoesBoom (Jun 6, 2011)

Yeah.. its 1 ohm stable. Other than headlights, my stock voltage gauge drops tremendously when its pounding. I can test to see exactly what my voltage drop is. Just meter the power terminals on the amp or what?


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## cubdenno (Nov 10, 2007)

yes. Simply put the appropriate leads on the positive and negative power terminals. I would set the min max function and play the most power hungry song at full tilt with car at idyl. I would also do that test withthe car revved to say 2k rpm on the same song. 

If you are dropping below 12v then you need to determine steps from there.


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## kyheng (Jan 31, 2007)

Try to run it at 2ohm or more......
Consider how current flow works....


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## MyJeepGoesBoom (Jun 6, 2011)

Its dual 2 ohm. So its 1 or 4. If I wanted to do that I would have bought a different amp/sub combo.

Anyway.. I took readings of my voltage drops. No music, sits steady at 13.9 (which I believe is normal). Full bore loudest I push it,at idle the biggest drop is to 10.52 on certain notes. If I rev her up to about 2k rpm, it drops to 12.48 on the same volume, same song and note.


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## kyheng (Jan 31, 2007)

Then go for 4ohms, at 1ohm, you are generating heat only... I will always change the wiring and see how it goes... Big numbers means nothing, if you don't know how to make power or control it....


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## MyJeepGoesBoom (Jun 6, 2011)

cajunner said:


> this says that unless you are revving the motor you should NOT run the system full tilt.
> 
> Consistent low voltage is bad for amplifiers.
> 
> consider getting a higher output alternator.




Well this I already know. The original question was that I have a high output battery that wont fit under the hood.. should I wire it up or not? The last thing I want is to burn my alt out. I really don't do much park and pound. The only time im not on the gas is maybe at a red light. I know the second battery will help, but the alt still has to strain to charge it. So in the long run is it a good choice?


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## MyJeepGoesBoom (Jun 6, 2011)

is this just as far as lower current alts? i know theres a guy outside of town that rebuilds them and could double it up to 180 amp. is that enough output? or could you point me in a good direction as far as alt outputs in relation to your amp draw?


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## MyJeepGoesBoom (Jun 6, 2011)

cajunner said:


> if you're going full tilt with the audio and your alternator you have now blows, it's tempting to take up one of these winding shops' offer of higher output.
> 
> a better plan might be to find a replacement alternator that can be retro-fitted to your vehicle that is designed from the start for the type of load you want out of it.
> 
> ...


He charges around 100 to 130 for rebuilds. Does really good work, lots of my buddies have gone to him and haven't had any issues at all. Probably give him a call and get some specifics tomorrow.

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## cubdenno (Nov 10, 2007)

Or

in my personal experience with my car, stock 80 amp alternator, like cajunner stated, reduce volume when you are not at a state of idyl. 

You can spend the money on an HO alt but with the power levels that you have, I am guessing your current alternator just does not have good idyl output. adding the second battery will help with that but you are also asking the alternator to charge the second battery as well after it is getting drained. 

determine your listening habits and base that on your purchasing decision. If you are pounding that system at all engine rpm's then accept that you "might" be shortening the life of your alternator. Add that second battery and make sure you put a battery tender on your system occasionally to keep them fully charged to help your alternator out. IF your stock alternator dies, decide then what you want to do.


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## Brucegbombara (Mar 30, 2011)

Hey guys I'm having a huge voltage drop too all of a sudden. I have a 2010 civic lx 0 gauge power wire and a kicker ix 500.4. Stock batt and alternator. When the car. Is off I'm getting 11.8v at the amp. As soon as I turn the car on it goes down to 5.8 my amp is in protection mode and won't come out cause of this. I haven't done the big 3 yet, do you think it will help?? I didn't think I would have a problem running a 500w amp off a stock alt and batt. I have a pioneer avic z130 besides that I have nothing else running off the batt. Do you think a HO alt is my only option?


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## kyheng (Jan 31, 2007)

Your grounding are properly done or not?


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## Brucegbombara (Mar 30, 2011)

My ground is like 6 inches from the amp going into a kicker grounding block. I have tightened it and taken both ends out and put them back in and tightened again.


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## kyheng (Jan 31, 2007)

I will prefer a direct run for ground also... It do solved my huge voltage drop issues....


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## Brucegbombara (Mar 30, 2011)

Run the ground right to the battery your saying ? Do you think the big3 or a deep cycle batt would help ?


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## kyheng (Jan 31, 2007)

Yup....If you got high resistance somewhere, doing big won't help... This is what you need to know first....


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## Brucegbombara (Mar 30, 2011)

So what about a deep cycle batt? It just has me nuts cause I'm getting almost 14v at the batt and after the inline fuse but at the trunk 10 ft away it's 5.8v when the car is running other wise when the car is off I have 11.9v. Thanks for your help though I do appreciate it. Wish I knew ppl on long island that could help. I just feel like I shouldn't need a HO alt with an amp that's only putting out 75rms to 4 channels. How do I check the ohms my amps speaker inputs are putting out? Just put my meter on ohms and put it in the - & + speaker leads?


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## MyJeepGoesBoom (Jun 6, 2011)

Brucegbombara said:


> How do I check the ohms my amps speaker inputs are putting out? Just put my meter on ohms and put it in the - & + speaker leads?


This doesn't have anything to do with your speakers or their impedances. Its about power and grounds. If you're losing voltage to it when you start the engine then there is some kind of short-to-ground or bad ground.

As far as your grounding block.. what is it attached to? Just because its attached to metal on the chassis doesn't make it a good ground. Bare metal or even grinding the paint off to make sure is the easiest. 
Have you changed any wiring up under the hood at all? If so, what?


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## Brucegbombara (Mar 30, 2011)

My ground block is attached to a piece of mdf that is mounted to my rear seat. I haven't changed any wiring under my hood


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## MyJeepGoesBoom (Jun 6, 2011)

cajunner said:


> make a new thread and show pics.


X2 - my thread got jacked


post link for new thread.


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## sqcomp (Sep 21, 2009)

I'll be doing something parallel to this in 5 weeks. I just purchased some new amplifiers that are current hogs...and with that I contacted an aftermarket alternator build house and have ordered a 320 Ampere drop in for my vehicle.

Even though I won't be pushing the amps nearly as hard as they can go, I still want to have the assurance of available Amperage. I've already replaced the stock batteries, I have a power supply for when I demo the vehicle, and I've already installed the Big 3 wiring upgrade.

If this topic is still around in that time frame, I'll post some pics up of the alternator, it's install and results from said install.


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## MyJeepGoesBoom (Jun 6, 2011)

In a jeep as well?


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## sqcomp (Sep 21, 2009)

No, however you'll be able to see the effect of an aftermarket alternator on an electrical system that is probably in it's stock form is a bit more weak than yours is, and has already been taken as far as it can go without one.


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## Brucegbombara (Mar 30, 2011)

Well my voltage drop issue was my ground!! My kicker ground block sucks for a ground!! Who would have thought??? Changed my ground to a different spot and whamo 14.4v. Thanks kicker!!


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## MyJeepGoesBoom (Jun 6, 2011)

Brucegbombara said:


> Well my voltage drop issue was my ground!! My kicker ground block sucks for a ground!! Who would have thought??? Changed my ground to a different spot and whamo 14.4v. Thanks kicker!!


That's what I was originally getting at. Just because its called a ground block doesn't mean you screw it to anywhere and it works. MDF definitely doesn't conduct any current, nor let it pass through. Its not kickers fault. Read the directions. "Attach to bare metal somewhere on the vehicle chassis." That closes the loop on the circuit. 

Plain and simple.

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