About how much power till 2nd alt

[truckaudioman 0]

Quick question. I will be running 4 18" BTL's. Upgrade wise, big 3, 300 amp alt, and about 4 kinetik 2400's.....i will be pushing about 12k watts to the subs as it is, roughly 3k each sub, well that is what i plan to push to each at least. I am about 90% positive i will need two alternators, what do you think?

[johnecon2001 82]

4 alts? You're way under powered. even with what you have planned.

[b5i8 0]

Power divided by volts gives you amps. In other words 12000W/12V = 1000A.

[power-fanatic07 0]

Power divided by volts gives you amps. In other words 12000W/12V = 1000A.

hm ive never heard that one before....is it true

[Patrick Simmons 0]

Power divided by volts gives you amps. In other words 12000W/12V = 1000A.

hm ive never heard that one before....is it true

Yes, according to ohms law but not always when it comes to real world applications.

[KickinAudio 5]

4 alts? You're way under powered. even with what you have planned.

I don't see anywhere where he said 4 alts. Thread title says "when is it time to run 2"

I don't think you'll need a second alt with that setup. Sure wouldn't hurt though.

[theabunai 3]

Actually that formula is for a 100% efficient amp....

You need to find the amps efficiency rating...

RMS (not max power) divided by Amps efficiency

Then Divided by volts (which is more like 13.8)

So lets do an example

1000 watt (mono @ 1 ohm) Divided by .8 (for an 80% eff. amp it means at 80% to get 1000 it needs to produce 1250 watts) = 1250

then we take this and divide by voltage

1250 / 13.8 (standard voltage system) = 90 amp draw...

Now some people say this amp draw is MAX draw for the amp on a test tone.... SOME say that music is 1/2 that draw (some say even 1/3rd but that is a but to much IMO) so we can take the 90 amp draw and divide by 2 for a 45 amp draw on music at listening levels...

The music part is to me sketchy I would go off MAX amp draw for MAX output on anything (test tone, music) since i believe not all music is recorded equally...

Someone correct me if i'm wrong though

[truckaudioman 0]

so what is lookin like to me is that start off with 1 300 amp alt, get all my stuff up and going, test everything. if it still pulls to much, then get another....

[audio-neon 34]

so what is lookin like to me is that start off with 1 300 amp alt, get all my stuff up and going, test everything. if it still pulls to much, then get another....

pretty much