I tried to look up past forums on this and had no luck. How much will a zx2500 draw at 2 ohms? Im gonna run 4 for a daily setup and im trying to figure out how many alts and what amperage alts i should run to properly supply these amps with enough amperage. thanks

You can figure this out with some basic math and reasoning skills.

Take the car's voltage on a good day, we'll use 14.4v as an example. Now take the rated power output at 2 ohms (2500 watts). Divide the wattage by the voltage. You should get around 173 as your number. Now this assumes that the amp is 100% efficient at that power level. You should assume about 70-80% efficiency on a good day. Figure each one draws around that 173 number though.

so if i get say 3 300amp alts does that mean if im demoing the car and have the rpms up then i wont have any drops in voltage? I would be sufficiently supplying all of my amps with more than enough amps then they are drawing total.

If you're demoing with music 1) you'll never run full power on those amps with someone in the car and 2) actual current draw will be more transient in nature and the alts aren't going to help much. You'd be better off with a big alt and a bank of batteries.

If you're demoing with music 1) you'll never run full power on those amps with someone in the car and 2) actual current draw will be more transient in nature and the alts aren't going to help much. You'd be better off with a big alt and a bank of batteries.

x2.

also, IIRC, james (dbdrag fellow and team kicker member) said something like 220amps full tilt@12volts on the zx2500. he said they were fairly efficient buggers.

wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

so if i give them atleast 880 amps from my alts why wont it the voltage stay high at full tilt? The batteries will only keep them from staying over like 12.7 volts or whatever right?

You fail to understand basic electrical draw.

If you have an alternator that is supposed to put out 220 amps at full tilt, that doesn't mean that it will put that out all the time. It will only put out that amount when something is drawing that amount.

In other words, if your beating around and its a reletively quiet part of a song and all of sudden the song gets loud.. you see a massive voltage drop as the alternators try to spool up all of a sudden to supply the amps with current.

Your batteries act as a buffer so that doesn't happen. And when you're running that much power, you need a large battery bank.

well if im demoing my system or whatever and have my rpms up will this voltage stay the same? With the setup i have would you go with like 3 220 amp alts which is a total of 520amps at idle or would you go with like 3 300 amp alternators and have more amps at peak and only 390 amps at idle. Im set on the amount of batteries im gonna run for this setup and its gonna be a total either 5 G3100 batts or 5 kinetik 2400's. So with those batts and my daily setup what would you do as far as the alts go?

a dual 220 would be plenty. with the batteries you have planned, that should be more then enough to suffice.

wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

well if im demoing my system or whatever and have my rpms up will this voltage stay the same? With the setup i have would you go with like 3 220 amp alts which is a total of 520amps at idle or would you go with like 3 300 amp alternators and have more amps at peak and only 390 amps at idle. Im set on the amount of batteries im gonna run for this setup and its gonna be a total either 5 G3100 batts or 5 kinetik 2400's. So with those batts and my daily setup what would you do as far as the alts go?

You're still not understanding what I said. Read it again. RPM's have nothing to do with it. They deal strictly with voltage output.

The alternators react to the draw, they are not instant. That is why if you turn on a high draw (but less than alt max) in the car the lights will dim for a moment until the alternator gets it together and puts out current to get voltage back up. You can see it on a volt gauge, like in my truck with a 190a when I hit the snowplow lift it drops then goes back to normal. It has a standard starter solenoid on it to run plow's hydraulic pump...and it has two 1K cca batteries. So it drops to ~12.5v on the batteries until the alt gets going, depending on how big or abrupt the draw is/etc. Of course that is all an amp does is put sudden high draws on.

I understand now...so what would you guys recommend in my case as far as how many alts and what size?

That was already answered.