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.

 

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...

 

I
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.

 

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

 

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.

 

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

 

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...

 

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.

 

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..."