# Safe voltage drop???



## Shadowmarx (Feb 12, 2012)

What would be considered a safe voltage drop for a Daily driven vehicle?
Safe as in for the electrical of the vehicle the amps and speakers.


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## stevenje98 (Feb 8, 2008)

A safe drop would be no more than 3 percent. 5 percent is pushing it. Don,t ever get below 11 volts though. You'll be buying batteries because of dead cells. Voltage drops for homes is not much different, 4 percent from your transformer. Cars are much more critical though because it's mostly DC.


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## Shadowmarx (Feb 12, 2012)

If i get 3% I'm good...
Well until I can upgrade my Alt.
I'm used to not get'n below 13.5 with headlights and AC on...
Couple new toys and bam I'm see'n 12.9/12.8
My Batt. sets at rest @ those numbers.
This is with a 150 amp Alt.
Sears platinum Batt. 
1/0 power and earth wire... (big three)
I still dont like those numbers. 
And See a 300-350 amp Alt. in my future.
I did look it up and just couldn't find anything with a clear definite answer..
If someone has a link to some good info, please share...
Thank you Sir...


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## IDGAF (Dec 27, 2009)

Anything below 12v going full tilt, you need more juice. 12.8 is fine but you're straining your alt pretty good there and it'll eventually go out on you. Adding a second battery will help until you get your alt. Even a super small one like this...

This little batt is tiny. It'll fit just about anywhere and it's good for an extra 1,000w of draw.

Audio Savings | XS Power D680 1000 Amp AGM Power Cell Car Audio Battery + Terminal Hardware


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## Shadowmarx (Feb 12, 2012)

Thats a nice little batt.
I was thinking of use'n another AGM Batt. to help out until I could get another Alt. Just didn't know if it would just put more of a load on my Alt. And thus not help my situation 'till i get a new HO Alt. 


IDGAF said:


> Anything below 12v going full tilt, you need more juice. 12.8 is fine but you're straining your alt pretty good there and it'll eventually go out on you. Adding a second battery will help until you get your alt. Even a super small one like this...
> 
> This little batt is tiny. It'll fit just about anywhere and it's good for an extra 1,000w of draw.
> 
> Audio Savings | XS Power D680 1000 Amp AGM Power Cell Car Audio Battery + Terminal Hardware


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## Serieus (May 27, 2011)

if you're pulling more amps than your alternator produces, why would an extra battery help? it's just more drain on the alternator and eventually that battery will drain out too and you're back to square one.

save your money and get a new alternator


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## Shadowmarx (Feb 12, 2012)

I'm look'n for a band-aid for a couple of weeks if I spend another 500 this week on audio... Well I will probable be washing the dishes and cook'n myself for a while...lolol...


Serieus said:


> if you're pulling more amps than your alternator produces, why would an extra battery help? it's just more drain on the alternator and eventually that battery will drain out too and you're back to square one.
> 
> save your money and get a new alternator


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## MarkZ (Dec 5, 2005)

Serieus said:


> if you're pulling more amps than your alternator produces, why would an extra battery help?


I've never heard of an audio system drawing more current long-term than the alternator produces, unless something was broken.


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## IDGAF (Dec 27, 2009)

Serieus said:


> if you're pulling more amps than your alternator produces, why would an extra battery help? it's just more drain on the alternator and eventually that battery will drain out too and you're back to square one.
> 
> save your money and get a new alternator





MarkZ said:


> I've never heard of an audio system drawing more current long-term than the alternator produces, unless something was broken.


You guys don't stray too far from this board, do you? Lol.


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## Maxxim (Sep 1, 2012)

Serieus said:


> if you're pulling more amps than your alternator produces, why would an extra battery help? it's just more drain on the alternator and eventually that battery will drain out too and you're back to square one.
> 
> save your money and get a new alternator


Its right!


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## Serieus (May 27, 2011)

MarkZ said:


> I've never heard of an audio system drawing more current long-term than the alternator produces, unless something was broken.


then he doesn't need another battery because the single one is fine obviously, it shouldn't deplete fast enough for the alternator to catch up


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## Shadowmarx (Feb 12, 2012)

I did install a power cell helped a lot... I think a little bigger one and it would be great. I'm not seeing below 13.1 Ac full blast and head lights on at idle...
This will hold me over till I can get a higher output Alt.
Thank you Sir...


IDGAF said:


> Anything below 12v going full tilt, you need more juice. 12.8 is fine but you're straining your alt pretty good there and it'll eventually go out on you. Adding a second battery will help until you get your alt. Even a super small one like this...
> 
> This little batt is tiny. It'll fit just about anywhere and it's good for an extra 1,000w of draw.
> 
> Audio Savings | XS Power D680 1000 Amp AGM Power Cell Car Audio Battery + Terminal Hardware


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## MarkZ (Dec 5, 2005)

IDGAF said:


> You guys don't stray too far from this board, do you? Lol.


Oh, I'd love to hear this one.

This forum is so ****ing electricity stupid, I can't believe we think we can actually tackle topics like acoustics here.


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## donnieL72 (Jun 20, 2012)

I thought this was settled by the collective masses.

Mark, want to be the ring master in the center ring of the circus? I'll take the one on the left with the clowns if someone else wants to take the one on the right with the elephants.


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## stevenje98 (Feb 8, 2008)

I


Shadowmarx said:


> If i get 3% I'm good...
> Well until I can upgrade my Alt.
> I'm used to not get'n below 13.5 with headlights and AC on...
> Couple new toys and bam I'm see'n 12.9/12.8
> ...


 That 3 percent figure is from the NEC -national electric code book. Hardcover. Cost about 150.00 bucks. Its was in the backsection under motor homes/ wiring , engies, charging systems , specifing examples from light duty trucks. That's the only source I ever found. Its only on a few pages. The nec never covers much in low volt. The publishers never post links either because its s professional manual, only citing the articles to the code..I wish they would or I would send a link to you. I asked s question like yours at a seminar one time.I was told Its all manufacture specific to the auto they build. Push came to shove and the big 3 us manufactures gave the NEC info which is not much. I don't think there is any published professional electrical code book other than the NEC with the info. It appears to be general guideline at best to avoid total electric failure in mobile charging systems. There has been some concerns about including more low volt specific Info in the NEC . I'm sure in the next few years we will all see the aftermarket audio car audio incorporated into a professional code book and regulated, I.e. National code, Like the NEC It only takes one lobbieist .then again. China would be pushed right out of the market. A good thing.


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## Shadowmarx (Feb 12, 2012)

Well no wonder I couldn't find any "real" information out there...
Shhh...Must be some big secret... lolol
Thanks again for take'n the time to share this information...


stevenje98 said:


> That 3 percent figure is from the NEC -national electric code book. Hardcover. Cost about 150.00 bucks. Its was in the backsection under motor homes/ wiring , engies, charging systems , specifing examples from light duty trucks. That's the only source I ever found. Its only on a few pages. The nec never covers much in low volt. The publishers never post links either because its s professional manual, only citing the articles to the code..I wish they would or I would send a link to you. I asked s question like yours at a seminar one time.I was told Its all manufacture specific to the auto they build. Push came to shove and the big 3 us manufactures gave the NEC info which is not much. I don't think there is any published professional electrical code book other than the NEC with the info. It appears to be general guideline at best to avoid total electric failure in mobile charging systems


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## IDGAF (Dec 27, 2009)

MarkZ said:


> Oh, I'd love to hear this one.
> 
> This forum is so ****ing electricity stupid, I can't believe we think we can actually tackle topics like acoustics here.


I didn't say anyone was wrong or didn't know what they were talking about, but you obviously don't visit some of the forums I do if you think people design their systems based solely on their alt's output.

I know people running upwards of 10kw on stock alt and 400-500Ah of batt. You reckon he's exceeding the long term output of his alt? Strange that his amp stays running. And yes, this a daily driven vehicle.

Adding a batt is adding reserve. It's not a "band-aid." An alt can't handle the enormous dynamic swings I deal with or multiple song, "walk away" demos these guys do on 5k, 10k... more? 

You have enough alt to run your whole system? Awesome. Doesn't mean everybody does. I run 5k+ on a stock 60A alt and happen to be one of the top 2 or 3 loudest people on the planet in my class. I guess I'm doing it wrong. 

How about when competitors get judged with the car off? Yeah, another batt is a terrible idea there, isn't it? But as long as his alternator is beefy enough, he should be fine, right?

You guys can cite percentage drops and NEC codes all you want, but a rather large portion of the of the CA world just adds whatever battery they can get their hands on until they dont' see 10v anymore when they clip the crap out of thier multi kilowatt amp running at .5 ohms.

I like the way things are done correctly around here. It's the way it should be. But you're not going to convince me not to run 5k daily until I get 500A worth of alt.

[Edit: I just saw your reply in another thread. I think we're on the same page. Not sure what you thought I was implying in my post for you to respond like that though.]


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## MarkZ (Dec 5, 2005)

IDGAF, wasn't referencing you. I was referencing the general attitude on this forum and the waaaaay overvaluing of electrical system issues. Amazingly, people are more worried about alternators than acoustics here. I'd guess by a 5:1 ratio.


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## IDGAF (Dec 27, 2009)

MarkZ said:


> IDGAF, wasn't referencing you. I was referencing the general attitude on this forum and the waaaaay overvaluing of electrical system issues. Amazingly, people are more worried about alternators than acoustics here. I'd guess by a 5:1 ratio.


10-4. I saw your posts in that other thread and was like, "Wait a minute..."


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## Shadowmarx (Feb 12, 2012)

I was going to over look this but....
I have to ask are u calling me "****ing stupid"???


MarkZ said:


> Oh, I'd love to hear this one.
> 
> This forum is so ****ing electricity stupid, I can't believe we think we can actually tackle topics like acoustics here.


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