Let's be realistic, a 4000 watt amplifier would draw 290 amps with a 13.8 volt source.You probably have a 70 amp alternator and out of those 70 amps you can dedicate 50 amps to the sound system.
50 amps times 13.8 volts equals 690 watts but that's with an amplifier that is 100% efficient.
Class A amplifiers are 30% efficient.
Class B amplifiers are 50% efficient.
Class AB amplifiers are 60% efficient.
Only Class D amplifiers are "theoretically" capable of reaching 100% efficiency.
The amplifier you chose is a Class D design so that's a plus BUT it only has three 40 amp fuses so 40 amps x 3 fuses = 120 amps and 120 amps x 13.8 volts = 1656 watts.
So, you will need at the minimum a 150 amp alternator to produce that 1656 watts with a 13.8 source voltage..
Let's say you have a 16 volt charging system, now all you need is 103 amps to produce 1656 watts so a 120/130 amp alternator would suffice..
Oh ****, I forgot to factor in voltage drop so now you need even more current to produce the same amount of power..
A good way to tell how much power an amplifier can produce is to multiply the number of fuses times the fuse rating..
If an amplifier has a single 50 amp fuse then the most power you can expect that amplifier to make is 690 watts, 13.8 x 50 = 690..
If an amplifier with three 40 amp fuses draws more than 120 amps what's going to happen, it'll blow the fuses..
Your amplifier would require three 100 amp fuses before it could even dream about making 4000 watts..
Hope this helps bring you back down to earth and let's you be more realistic with your power expectations..
I don't think it's helping anyone trying to dumb down the abilities of a car's electrical system in relation to powering an audio amplifier.
For starters - if we're dealing with a 70A Alternator we must be dealing with an import at least a couple decades old, so from the start that's probably not a great assumption.
The rest of your breakdown assumes everyone listens exclusively to low frequency test tones and plays them at full volume constantly.
I don't think that's what the average listener does.
Yes - a ~1000w rms amp CAN draw 100-130A depending on efficiency, but realistically - playing music it a moderate or even high volume the actual current demand wouldn't even be half that.
There's no reason to expect this amp not to run perfectly fine in a car with an average size alternator and battery.
OG, what we're trying to help you understand is the amp isn't capable of what you think it is. There's no possible way it'll do 1800w. If you believe that was somehow tested/measured, then I can guarantee you there was an error in the measurement.
It's a budget amp, capable of around 1000w, and should run your sub fine at 1 ohm. And there's no reason you can't be perfectly satisfied with it. I've certainly had my share of budget gear, and will still go that route when the situation calls for it.
You should be careful with the tuning of the amp though - as Kickers don't have the greatest reputation for power handling. Plus, cheap amps don't tend to last long when running hard at minimum impedance.
Hopefully it will hold up well for you. If you're in the market for an upgrade anytime soon ask for ideas BEFORE you buy.
