Originally Posted by profundus-sanus

Voltage Drop Calculator

this is what i use.

its 1/2 loop resistance input but calculates full loop.. as you'll have voltage drop on ground and positive.. Thats why my numbers where much higher than fallens... As mine were assuming the chassis had similar resistance to the 4 gauge.

Originally Posted by Fallen

Probably. I would check with a dmm to be sure. The accuracy on some of those voltmeters is questionable at best.

The thing is, if we're talking music, and not pure tones, then the current draw will not be constant. That'll give things a chance to charge. Who knows what the refresh rate is on those voltmeters.

But yeah, instead of getting too technical, just upgrade the damn wire. Leave the 4awg for ground . (and use the chassis in parallel with it)
That would minimize effort.

Originally Posted by Fallen

Voltmeter doesn't measure current draw or power

Ok anyways point is, you'll drop some voltage across the wire. (regardless of Honda or Ford). My numbers could be off, since car audio wire isn't really standardized. Sometimes it's oversized, undersized who knows. Also the assumption about the drop at the alt could be exagerated in your case. Who knows.

I do know one thing. If there's any current flowing through a wire, there will be a voltage dropped across it. It isn't ohms theory, or ohms suggestion, it's a law.

That said I also omitted the role of batteries. They make analysis even more fun. They're even less ideal voltage sources than alternators.

Originally Posted by Fallen

Did you actually measure the current draw and the power out from the amp?
Ohms law doesn't lie

When I'm not drawing much current (say daily driving) my voltages sit nice and high. IT's when you're drawing hundreds of amps when things really take a nose dive.

The difference in current draw between 3dB is half, But to the ear it's not a big difference. It may seem quite loud when drawing only say 30-40A. (especially since there's less of a drop, and the voltage at the amp would be higher, increasing it's output a bit)

Originally Posted by SolemnSinner

I was getting 14.6 with the AQ2200 in the CRX and a 165 amp alternator.

Originally Posted by sri3850341

like drinking mcdonalds shake through ****tail straw

Originally Posted by profundus-sanus

the alt regulator will adjust voltage based on what it sees on its output terminals, not what the amp is seeing. it'll compensate for that 125a draw and still put out 14.4 at its terminals... but it wont compensate for wire losses.

running 125 amps through 4 gauge thats 17ft loong will net you around 1.3v drop by the end of the wire assuming its ofc 4 gauge, or 1.8v drop on cca.

so if your alt is putting 14.4 out you'll see 13.1v at the end of the wire under full load conditions with ofc or 12.6v under full load with cca.

now on low volume you'll see pretty much exactly what you'll have under the hood.

Originally Posted by SolemnSinner

No, it drops into the 12's at 1200 rms @ 1ohm with the stocker alt.

Still though, wouldn't the 250 amp alt keep me around 13.5 even when jamming it?

Originally Posted by sri3850341

lol, it blocked it, c o c k t a i l straw

Originally Posted by sri3850341

like drinking mcdonalds shake through ****tail straw