Amperage per watt

[BooLeaN 10+ year member]

Hey I was wondering how many watts can be run off a 100 amp alternator. Class D power. I am installing a system in my friend's car tomorrow and his alternator is 105 amps. I am going to be puttin in a AB cx1200D amp (80 amp fuse). Also in my car the BIGGEST alternator I can find is 120 amp, but I want to run 2 AB 1200's and my zapco ag 350. Totallying 200 amps of fuses.

Thanks

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[MXJMR 10+ year member]

http://www.the12volt.com/ohm/page2.asp#16

I have no clue how to figure that out but u mind be able to find some round about answer from ohms law. P=amps^2 x Ohms

 

[helotaxi 5,000+ posts]

P=IV*eff would be a better equation for this.

Assuming a 80% efficiency best case for a class D, and 14.4V nominal with the car on. 25A to run the car, ballpark without headlights, 45-65 with. Leaves a margin of from 40-80 amps to run your system without dipping into the battery. From 460-920 watts with a 105A alt. More than enough to listen to music.

 

[MXJMR 10+ year member]

P=IE* :thumbsup

 

[BooLeaN 10+ year member]

Thanks all!!

 

[n2audio 5,000+ posts]

A couple thousand - give or take.