Current = Power / Voltage. So 2000 Watts / 12.5Volts (in car voltage) = 160 Amps.

The amount of average power you will use with music depends upon you as a listener. Most people will use 20% of the amplifier's energy with music. In this case 2000 Watts x .2 = 400 Watts on average. The amp will need to pull 800 Watts to produce this average power out which means and average current draw of 64 amps with music.

If you were an abusive user (most people who want 2000 Watts on two octaves usually are) you would average 50% of the amplifiers energy with music 2000 Watts x .5 = 1000 Watts x 2 =2000 Watts / 12.5V = 160 amps average.

The vehicle itself will need 40 - 60 amps to operate. If the OEM Scion alternator is 90 amps and the car will only use 40 amps, there is only 50 amps for the system (50 amps x 12.5V = 625 Watts). All energy to move a speaker ultimately comes from the alternator. The amp simply converts the energy from the alternator to something useful to move a speaker. On a good day the OEM alternator has 625 Watts to give to the audio system. The amplifier cannot produce more average energy than the alternator has to give. The addition of batteries and capacitors will not change this. These devices need to be re-charged at some point and that comes from the alternator.

So basically, no matter what the amp manufacturer says, the amp is bound by the alternator's output. If the amplifier uses a non-regulated power supply, it's output will drop as voltage sags. Non-regulated amps are less abusive to charging systems, but their output changes with input. Regulated power supplies will draw more current as voltage drops to maintain output. You get what you pay for over a wide voltage range, but it's more taxing on the charging system. Regulation is typically more expensive so the retail price will often be more than a non-regulated amp.

Since the 1000/1 was mentioned and prices of other amps are being thrown around I will use it as an example. To compare apples to apples you must first equal the playing field. Many amps are rated using CEA 2006 standard. The 1000/1 is rated with 12.5V input .05%THD. The CEA standard is 14.4V input 1%THD. To compare the two equally take the CEA number and multiply it by .7. So an amp rated at 1000

[email protected] 14.4V would produce 700 Watts at true "in car" voltage under load. If the 1000/1 retailed for $1000 it would cost $1 per Watt. The other amp retails for $600 which makes it $.86 per Watt. This assumes the car can maintain the 12.5V base under load (it often cannot). So lets say voltage sags to 10.5V (very common) the 1000/1 will still be a 1000 Watt amp (although drawing more current) the other amp is now producing 490 Watts making the Watt per dollar average increase to $1.22 per Watt.

JL Audio produces both regulated and non-regulated amps (both rated at true "in car" voltage). Both have their place in the world. The bottom line is most OEM charging systems cannot supply the current needed for a 1000+Watt system in the hands of an abusive listener. I don't know of any car whose charging system can be upgraded to handle two 1000/1 amplifiers in the hands of someone with digital a volume control (full or off). In the case of the "Slash" series amps you are always dealing with true Watts. If the amps do not have enough voltage to produce rated power, they will shut off (low voltage protection).

P.S.

Your wiring will need to be upgraded.

P.P.S

If you already have a 1000 Watt amp (non-regulated) and the charging system is already overwhelmed, adding a second will produce no more output. The alt's output is now split so both amps will produce the same total power as the first. If you have no plans to upgrade your charging system (and wire) do not bother. If you do upgrade, the output will increase 3dB which is the minumum humans can detect easily with music (as depressing as that sounds). The Porsche only runs on premuim fuel!

P.P.S.

It takes power to make power!

P.P.P.S.

The 1000/1 will not lose power at higher impedance like other amp designs. The amp will produce 1000 Watts from 1.5 ohm - 4ohm.

Had to edit my math