What's considered a bad voltage drop?

[tsenfw 10+ year member]

What would be an acceptable voltage drop? Measuring at the amp on idle I got:

at rest 14.1v - 14.2v

music up 13.8v - 13.9v

This was measured at the component amp side and mono amp side. Does it matter which amp you measure from? Should be the same right?

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[Supergumby5000 5,000+ posts]

thats not a bad drop at all

 

[J31Rob 5,000+ posts]

very nice, you're hardly dropping at ALL.

when you get under 13, is when you should start seeking a beefier electrical.

you'd be FINE down to about 12, but most amps are rated 13+ volts, so why slack off..

 

[jmanpc 5,000+ posts]

Under 12 = fail

 

[tsenfw 10+ year member]

Cool, yeah i was wondering the thresholds. So could voltage be lower at the sub amp compared to the component amp? Or will the readings be exactly the same?

 

[treasony 10+ year member]

13.8- .9 is good, what setup you running?

 

[tothemax1984]

how about down to 12.4? when the bass hits.

 

[tsenfw 10+ year member]

2000 3.8 mustang

stock 130amp alternator

Big 3 with 4 gauge

yellowtop up front

directed d2400 (1000 watts) on 12" mag

JL 300/4 with pioneer rev's

 

[MikeyB 5,000+ posts]

I dont get any drop unless im stopped for a moment, playing full tilt in drive. If i pop it into neutral or park the rpm pick up about 200 or so and my alt puts out enough current to power everything fine. Most drop I have ever seen is ~12

 

[knukonceptz 10+ year member]

I'd start at the front, check battery voltage at idle. then with system on, then repeat in the trunk.

 

[n2audio 5,000+ posts]

how about down to 12.4? when the bass hits.

Not the end of the world, but it's not good.

Your alt must be straining pretty hard.

I used to have around 1000w on a 75A alt. At idle I could measure voltages as low as 11.9 depending on what accessories were on. However, at 2k or so it maintained 13v.

It ran like that for about 2 yrs before the alt finally bit it.